/*
** Generate code for the ANALYZE command. The parser calls this routine
** when it recognizes an ANALYZE command.
**
** ANALYZE -- 1
** ANALYZE <database> -- 2
** ANALYZE ?<database>.?<tablename> -- 3
**
** Form 1 causes all indices in all attached databases to be analyzed.
** Form 2 analyzes all indices the single database named.
** Form 3 analyzes all indices associated with the named table.
*/
void sqlite3Analyze(Parse *pParse, Token *pName1, Token *pName2){
sqlite3 *db = pParse->db;
int iDb;
int i;
char *z, *zDb;
Table *pTab;
Index *pIdx;
Token *pTableName;
/* Read the database schema. If an error occurs, leave an error message
** and code in pParse and return NULL. */
assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
return;
}
assert( pName2!=0 || pName1==0 );
if( pName1==0 ){
/* Form 1: Analyze everything */
for(i=0; i<db->nDb; i++){
if( i==1 ) continue; /* Do not analyze the TEMP database */
analyzeDatabase(pParse, i);
}
}else if( pName2->n==0 ){
/* Form 2: Analyze the database or table named */
iDb = sqlite3FindDb(db, pName1);
if( iDb>=0 ){
analyzeDatabase(pParse, iDb);
}else{
z = sqlite3NameFromToken(db, pName1);
if( z ){
if( (pIdx = sqlite3FindIndex(db, z, 0))!=0 ){
analyzeTable(pParse, pIdx->pTable, pIdx);
}else if( (pTab = sqlite3LocateTable(pParse, 0, z, 0))!=0 ){
analyzeTable(pParse, pTab, 0);
}
sqlite3DbFree(db, z);
}
}
}else{
/* Form 3: Analyze the fully qualified table name */
iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pTableName);
if( iDb>=0 ){
zDb = db->aDb[iDb].zName;
z = sqlite3NameFromToken(db, pTableName);
if( z ){
if( (pIdx = sqlite3FindIndex(db, z, zDb))!=0 ){
analyzeTable(pParse, pIdx->pTable, pIdx);
}else if( (pTab = sqlite3LocateTable(pParse, 0, z, zDb))!=0 ){
analyzeTable(pParse, pTab, 0);
}
sqlite3DbFree(db, z);
}
}
}
}
/*
** Look up every table that is named in pSrc. If any table is not found,
** add an error message to pParse->zErrMsg and return NULL. If all tables
** are found, return a pointer to the last table.
*/
Table *sqlite3SrcListLookup(Parse *pParse, SrcList *pSrc){
Table *pTab = 0;
int i;
struct SrcList_item *pItem;
for(i=0, pItem=pSrc->a; i<pSrc->nSrc; i++, pItem++){
pTab = sqlite3LocateTable(pParse, pItem->zName, pItem->zDatabase);
pItem->pTab = pTab;
}
return pTab;
}
/*
** Look up every table that is named in pSrc. If any table is not found,
** add an error message to pParse->zErrMsg and return NULL. If all tables
** are found, return a pointer to the last table.
*/
Table *sqlite3SrcListLookup(Parse *pParse, SrcList *pSrc) {
Table *pTab = 0;
int i;
for(i=0; i<pSrc->nSrc; i++) {
const char *zTab = pSrc->a[i].zName;
const char *zDb = pSrc->a[i].zDatabase;
pTab = sqlite3LocateTable(pParse, zTab, zDb);
pSrc->a[i].pTab = pTab;
}
return pTab;
}
/*
** Look up every table that is named in pSrc. If any table is not found,
** add an error message to pParse->zErrMsg and return NULL. If all tables
** are found, return a pointer to the last table.
*/
Table *sqlite3SrcListLookup(Parse *pParse, SrcList *pSrc){
struct SrcList_item *pItem = pSrc->a;
Table *pTab;
assert( pItem && pSrc->nSrc==1 );
pTab = sqlite3LocateTable(pParse, 0, pItem->zName, pItem->zDatabase);
sqlite3DeleteTable(pParse->db, pItem->pTab);
pItem->pTab = pTab;
if( pTab ){
pTab->nRef++;
}
if( sqlite3IndexedByLookup(pParse, pItem) ){
pTab = 0;
}
return pTab;
}
/*
** While a SrcList can in general represent multiple tables and subqueries
** (as in the FROM clause of a SELECT statement) in this case it contains
** the name of a single table, as one might find in an INSERT, DELETE,
** or UPDATE statement. Look up that table in the symbol table and
** return a pointer. Set an error message and return NULL if the table
** name is not found or if any other error occurs.
**而SrcList可以在代表多个表和子查询（如在从SELECT语句的子句）在此情况下，它含有（如在FROM SELECT语句的子句）在此情况下，它包含单个表的名称，因为可能会发现一个INSERT，DELETE或UPDATE语句。查找该表中的符号表，并返回一个指针。设置一个错误信息，如果表名没有找到返回NULL，或如果发生任何错误。
** The following fields are initialized appropriate in pSrc:
**在pSrc初始化以下字段:
** pSrc->a[0].pTab Pointer to the Table object 指向目标表
** pSrc->a[0].pIndex Pointer to the INDEXED BY index, if there is one 有INDEXED BY语句的指向INDEXED BY 索引
**
*/
Table *sqlite3SrcListLookup(Parse *pParse, SrcList *pSrc){
//函数的作用查找所有名字为pSrc的表，如果没有找到任何表，添加一个错误消息pParse - > zErrMsg并返回NULL。如果所有的表都找到，返回一个指针，指向最后一个表。
struct SrcList_item *pItem = pSrc->a;
Table *pTab;
assert( pItem && pSrc->nSrc==1 );
pTab = sqlite3LocateTable(pParse, 0, pItem->zName, pItem->zDatabase);
//这个函数定位pItem所指的表所在的数据库，表的名字，并用指针pTab指向该定位的表
sqlite3DeleteTable(pParse->db, pItem->pTab);
//功能：删除该表 ，但是还没有调用该函数
pItem->pTab = pTab;
if( pTab ){//如果这个表存在，则逐一检查这个表中的参数
pTab->nRef++;
}
if( sqlite3IndexedByLookup(pParse, pItem) ){//如果通过查找索引和该表匹配，则0表示要找的就是这个表
pTab = 0;
}
return pTab;
}
/*
** This routine is called after all of the trigger actions have been parsed
** in order to complete the process of building the trigger.
*/
void sqlite3FinishTrigger(
Parse *pParse, /* Parser context */
TriggerStep *pStepList, /* The triggered program */
Token *pAll /* Token that describes the complete CREATE TRIGGER */
){
Trigger *nt = 0; /* The trigger whose construction is finishing up */
sqlite *db = pParse->db; /* The database */
DbFixer sFix;
if( pParse->nErr || pParse->pNewTrigger==0 ) goto triggerfinish_cleanup;
nt = pParse->pNewTrigger;
pParse->pNewTrigger = 0;
nt->step_list = pStepList;
while( pStepList ){
pStepList->pTrig = nt;
pStepList = pStepList->pNext;
}
if( sqlite3FixInit(&sFix, pParse, nt->iDb, "trigger", &nt->nameToken)
&& sqlite3FixTriggerStep(&sFix, nt->step_list) ){
goto triggerfinish_cleanup;
}
/* if we are not initializing, and this trigger is not on a TEMP table,
** build the sqlite_master entry
*/
if( !db->init.busy ){
static VdbeOpList insertTrig[] = {
{ OP_NewRecno, 0, 0, 0 },
{ OP_String8, 0, 0, "trigger" },
{ OP_String8, 0, 0, 0 }, /* 2: trigger name */
{ OP_String8, 0, 0, 0 }, /* 3: table name */
{ OP_Integer, 0, 0, 0 },
{ OP_String8, 0, 0, "CREATE TRIGGER "},
{ OP_String8, 0, 0, 0 }, /* 6: SQL */
{ OP_Concat8, 2, 0, 0 },
{ OP_MakeRecord, 5, 0, "tttit" },
{ OP_PutIntKey, 0, 0, 0 },
};
int addr;
Vdbe *v;
/* Make an entry in the sqlite_master table */
v = sqlite3GetVdbe(pParse);
if( v==0 ) goto triggerfinish_cleanup;
sqlite3BeginWriteOperation(pParse, 0, nt->iDb);
sqlite3OpenMasterTable(v, nt->iDb);
addr = sqlite3VdbeAddOpList(v, ArraySize(insertTrig), insertTrig);
sqlite3VdbeChangeP3(v, addr+2, nt->name, 0);
sqlite3VdbeChangeP3(v, addr+3, nt->table, 0);
sqlite3VdbeChangeP3(v, addr+6, pAll->z, pAll->n);
if( nt->iDb!=0 ){
sqlite3ChangeCookie(db, v, nt->iDb);
}
sqlite3VdbeAddOp(v, OP_Close, 0, 0);
sqlite3EndWriteOperation(pParse);
}
if( !pParse->explain ){
Table *pTab;
sqlite3HashInsert(&db->aDb[nt->iDb].trigHash,
nt->name, strlen(nt->name)+1, nt);
pTab = sqlite3LocateTable(pParse, nt->table, db->aDb[nt->iTabDb].zName);
assert( pTab!=0 );
nt->pNext = pTab->pTrigger;
pTab->pTrigger = nt;
nt = 0;
}
triggerfinish_cleanup:
sqlite3DeleteTrigger(nt);
sqlite3DeleteTrigger(pParse->pNewTrigger);
pParse->pNewTrigger = 0;
sqlite3DeleteTriggerStep(pStepList);
}
/*
** This function is called by the parser after the table-name in
** an "ALTER TABLE <table-name> ADD" statement is parsed. Argument
** pSrc is the full-name of the table being altered.
**
** This routine makes a (partial) copy of the Table structure
** for the table being altered and sets Parse.pNewTable to point
** to it. Routines called by the parser as the column definition
** is parsed (i.e. sqlite3AddColumn()) add the new Column data to
** the copy. The copy of the Table structure is deleted by tokenize.c
** after parsing is finished.
**
** Routine sqlite3AlterFinishAddColumn() will be called to complete
** coding the "ALTER TABLE ... ADD" statement.
*/
void sqlite3AlterBeginAddColumn(Parse *pParse, SrcList *pSrc){
Table *pNew;
Table *pTab;
Vdbe *v;
int iDb;
int i;
int nAlloc;
/* Look up the table being altered. */
assert( pParse->pNewTable==0 );
if( sqlite3MallocFailed() ) goto exit_begin_add_column;
pTab = sqlite3LocateTable(pParse, pSrc->a[0].zName, pSrc->a[0].zDatabase);
if( !pTab ) goto exit_begin_add_column;
#ifndef SQLITE_OMIT_VIRTUALTABLE
if( IsVirtual(pTab) ){
sqlite3ErrorMsg(pParse, "virtual tables may not be altered");
goto exit_begin_add_column;
}
#endif
/* Make sure this is not an attempt to ALTER a view. */
if( pTab->pSelect ){
sqlite3ErrorMsg(pParse, "Cannot add a column to a view");
goto exit_begin_add_column;
}
assert( pTab->addColOffset>0 );
iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
/* Put a copy of the Table struct in Parse.pNewTable for the
** sqlite3AddColumn() function and friends to modify.
*/
pNew = (Table *)sqliteMalloc(sizeof(Table));
if( !pNew ) goto exit_begin_add_column;
pParse->pNewTable = pNew;
pNew->nRef = 1;
pNew->nCol = pTab->nCol;
assert( pNew->nCol>0 );
nAlloc = (((pNew->nCol-1)/8)*8)+8;
assert( nAlloc>=pNew->nCol && nAlloc%8==0 && nAlloc-pNew->nCol<8 );
pNew->aCol = (Column *)sqliteMalloc(sizeof(Column)*nAlloc);
pNew->zName = sqliteStrDup(pTab->zName);
if( !pNew->aCol || !pNew->zName ){
goto exit_begin_add_column;
}
memcpy(pNew->aCol, pTab->aCol, sizeof(Column)*pNew->nCol);
for(i=0; i<pNew->nCol; i++){
Column *pCol = &pNew->aCol[i];
pCol->zName = sqliteStrDup(pCol->zName);
pCol->zColl = 0;
pCol->zType = 0;
pCol->pDflt = 0;
}
pNew->pSchema = pParse->db->aDb[iDb].pSchema;
pNew->addColOffset = pTab->addColOffset;
pNew->nRef = 1;
/* Begin a transaction and increment the schema cookie. */
sqlite3BeginWriteOperation(pParse, 0, iDb);
v = sqlite3GetVdbe(pParse);
if( !v ) goto exit_begin_add_column;
sqlite3ChangeCookie(pParse->db, v, iDb);
exit_begin_add_column:
sqlite3SrcListDelete(pSrc);
return;
}
/*
** Generate code to implement the "ALTER TABLE xxx RENAME TO yyy"
** command.
*/
void sqlite3AlterRenameTable(
Parse *pParse, /* Parser context. */
SrcList *pSrc, /* The table to rename. */
Token *pName /* The new table name. */
){
int iDb; /* Database that contains the table */
char *zDb; /* Name of database iDb */
Table *pTab; /* Table being renamed */
char *zName = 0; /* NULL-terminated version of pName */
sqlite3 *db = pParse->db; /* Database connection */
int nTabName; /* Number of UTF-8 characters in zTabName */
const char *zTabName; /* Original name of the table */
Vdbe *v;
#ifndef SQLITE_OMIT_TRIGGER
char *zWhere = 0; /* Where clause to locate temp triggers */
#endif
int isVirtualRename = 0; /* True if this is a v-table with an xRename() */
if( sqlite3MallocFailed() ) goto exit_rename_table;
assert( pSrc->nSrc==1 );
pTab = sqlite3LocateTable(pParse, pSrc->a[0].zName, pSrc->a[0].zDatabase);
if( !pTab ) goto exit_rename_table;
iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
zDb = db->aDb[iDb].zName;
/* Get a NULL terminated version of the new table name. */
zName = sqlite3NameFromToken(pName);
if( !zName ) goto exit_rename_table;
/* Check that a table or index named 'zName' does not already exist
** in database iDb. If so, this is an error.
*/
if( sqlite3FindTable(db, zName, zDb) || sqlite3FindIndex(db, zName, zDb) ){
sqlite3ErrorMsg(pParse,
"there is already another table or index with this name: %s", zName);
goto exit_rename_table;
}
/* Make sure it is not a system table being altered, or a reserved name
** that the table is being renamed to.
*/
if( strlen(pTab->zName)>6 && 0==sqlite3StrNICmp(pTab->zName, "sqlite_", 7) ){
sqlite3ErrorMsg(pParse, "table %s may not be altered", pTab->zName);
goto exit_rename_table;
}
if( SQLITE_OK!=sqlite3CheckObjectName(pParse, zName) ){
goto exit_rename_table;
}
#ifndef SQLITE_OMIT_AUTHORIZATION
/* Invoke the authorization callback. */
if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab->zName, 0) ){
goto exit_rename_table;
}
#endif
#ifndef SQLITE_OMIT_VIRTUALTABLE
if( sqlite3ViewGetColumnNames(pParse, pTab) ){
goto exit_rename_table;
}
if( IsVirtual(pTab) && pTab->pMod->pModule->xRename ){
isVirtualRename = 1;
}
#endif
/* Begin a transaction and code the VerifyCookie for database iDb.
** Then modify the schema cookie (since the ALTER TABLE modifies the
** schema). Open a statement transaction if the table is a virtual
** table.
*/
v = sqlite3GetVdbe(pParse);
if( v==0 ){
goto exit_rename_table;
}
sqlite3BeginWriteOperation(pParse, isVirtualRename, iDb);
sqlite3ChangeCookie(db, v, iDb);
/* If this is a virtual table, invoke the xRename() function if
** one is defined. The xRename() callback will modify the names
** of any resources used by the v-table implementation (including other
** SQLite tables) that are identified by the name of the virtual table.
*/
#ifndef SQLITE_OMIT_VIRTUALTABLE
if( isVirtualRename ){
sqlite3VdbeOp3(v, OP_String8, 0, 0, zName, 0);
sqlite3VdbeOp3(v, OP_VRename, 0, 0, (const char*)pTab->pVtab, P3_VTAB);
}
#endif
/* figure out how many UTF-8 characters are in zName */
zTabName = pTab->zName;
nTabName = sqlite3Utf8CharLen(zTabName, -1);
/* Modify the sqlite_master table to use the new table name. */
sqlite3NestedParse(pParse,
"UPDATE %Q.%s SET "
#ifdef SQLITE_OMIT_TRIGGER
"sql = sqlite_rename_table(sql, %Q), "
#else
"sql = CASE "
"WHEN type = 'trigger' THEN sqlite_rename_trigger(sql, %Q)"
"ELSE sqlite_rename_table(sql, %Q) END, "
#endif
"tbl_name = %Q, "
"name = CASE "
"WHEN type='table' THEN %Q "
"WHEN name LIKE 'sqlite_autoindex%%' AND type='index' THEN "
"'sqlite_autoindex_' || %Q || substr(name,%d+18,10) "
"ELSE name END "
"WHERE tbl_name=%Q AND "
"(type='table' OR type='index' OR type='trigger');",
zDb, SCHEMA_TABLE(iDb), zName, zName, zName,
#ifndef SQLITE_OMIT_TRIGGER
zName,
#endif
zName, nTabName, zTabName
);
#ifndef SQLITE_OMIT_AUTOINCREMENT
/* If the sqlite_sequence table exists in this database, then update
** it with the new table name.
*/
if( sqlite3FindTable(db, "sqlite_sequence", zDb) ){
sqlite3NestedParse(pParse,
"UPDATE %Q.sqlite_sequence set name = %Q WHERE name = %Q",
zDb, zName, pTab->zName);
}
#endif
#ifndef SQLITE_OMIT_TRIGGER
/* If there are TEMP triggers on this table, modify the sqlite_temp_master
** table. Don't do this if the table being ALTERed is itself located in
** the temp database.
*/
if( (zWhere=whereTempTriggers(pParse, pTab))!=0 ){
sqlite3NestedParse(pParse,
"UPDATE sqlite_temp_master SET "
"sql = sqlite_rename_trigger(sql, %Q), "
"tbl_name = %Q "
"WHERE %s;", zName, zName, zWhere);
sqliteFree(zWhere);
}
#endif
/* Drop and reload the internal table schema. */
reloadTableSchema(pParse, pTab, zName);
exit_rename_table:
sqlite3SrcListDelete(pSrc);
sqliteFree(zName);
}
/*
** This function is called by the parser after the table-name in
** an "ALTER TABLE <table-name> ADD" statement is parsed. Argument
** pSrc is the full-name of the table being altered.
**
** This routine makes a (partial) copy of the Table structure
** for the table being altered and sets Parse.pNewTable to point
** to it. Routines called by the parser as the column definition
** is parsed (i.e. sqlite3AddColumn()) add the new Column data to
** the copy. The copy of the Table structure is deleted by tokenize.c
** after parsing is finished.
**
** Routine sqlite3AlterFinishAddColumn() will be called to complete
** coding the "ALTER TABLE ... ADD" statement.
*/
void sqlite3AlterBeginAddColumn(Parse *pParse, SrcList *pSrc){
Table *pNew;
Table *pTab;
Vdbe *v;
int iDb;
int i;
int nAlloc;
sqlite3 *db = pParse->db;
/* Look up the table being altered. */
assert( pParse->pNewTable==0 );
assert( sqlite3BtreeHoldsAllMutexes(db) );
if( db->mallocFailed ) goto exit_begin_add_column;
pTab = sqlite3LocateTable(pParse, 0, pSrc->a[0].zName, pSrc->a[0].zDatabase);
if( !pTab ) goto exit_begin_add_column;
#ifndef SQLITE_OMIT_VIRTUALTABLE
if( IsVirtual(pTab) ){
sqlite3ErrorMsg(pParse, "virtual tables may not be altered");
goto exit_begin_add_column;
}
#endif
/* Make sure this is not an attempt to ALTER a view. */
if( pTab->pSelect ){
sqlite3ErrorMsg(pParse, "Cannot add a column to a view");
goto exit_begin_add_column;
}
assert( pTab->addColOffset>0 );
iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
/* Put a copy of the Table struct in Parse.pNewTable for the
** sqlite3AddColumn() function and friends to modify. But modify
** the name by adding an "sqlite_altertab_" prefix. By adding this
** prefix, we insure that the name will not collide with an existing
** table because user table are not allowed to have the "sqlite_"
** prefix on their name.
*/
pNew = (Table*)sqlite3DbMallocZero(db, sizeof(Table));
if( !pNew ) goto exit_begin_add_column;
pParse->pNewTable = pNew;
pNew->nRef = 1;
pNew->db = db;
pNew->nCol = pTab->nCol;
assert( pNew->nCol>0 );
nAlloc = (((pNew->nCol-1)/8)*8)+8;
assert( nAlloc>=pNew->nCol && nAlloc%8==0 && nAlloc-pNew->nCol<8 );
pNew->aCol = (Column*)sqlite3DbMallocZero(db, sizeof(Column)*nAlloc);
pNew->zName = sqlite3MPrintf(db, "sqlite_altertab_%s", pTab->zName);
if( !pNew->aCol || !pNew->zName ){
db->mallocFailed = 1;
goto exit_begin_add_column;
}
memcpy(pNew->aCol, pTab->aCol, sizeof(Column)*pNew->nCol);
for(i=0; i<pNew->nCol; i++){
Column *pCol = &pNew->aCol[i];
pCol->zName = sqlite3DbStrDup(db, pCol->zName);
pCol->zColl = 0;
pCol->zType = 0;
pCol->pDflt = 0;
}
pNew->pSchema = db->aDb[iDb].pSchema;
pNew->addColOffset = pTab->addColOffset;
pNew->nRef = 1;
/* Begin a transaction and increment the schema cookie. */
sqlite3BeginWriteOperation(pParse, 0, iDb);
v = sqlite3GetVdbe(pParse);
if( !v ) goto exit_begin_add_column;
sqlite3ChangeCookie(pParse, iDb);
exit_begin_add_column:
sqlite3SrcListDelete(db, pSrc);
return;
}
/*
** Open a blob handle.
*/
int sqlite3_blob_open(
sqlite3* db, /* The database connection */
const char *zDb, /* The attached database containing the blob */
const char *zTable, /* The table containing the blob */
const char *zColumn, /* The column containing the blob */
sqlite_int64 iRow, /* The row containing the glob */
int flags, /* True -> read/write access, false -> read-only */
sqlite3_blob **ppBlob /* Handle for accessing the blob returned here */
){
int nAttempt = 0;
int iCol; /* Index of zColumn in row-record */
/* This VDBE program seeks a btree cursor to the identified
** db/table/row entry. The reason for using a vdbe program instead
** of writing code to use the b-tree layer directly is that the
** vdbe program will take advantage of the various transaction,
** locking and error handling infrastructure built into the vdbe.
**
** After seeking the cursor, the vdbe executes an OP_ResultRow.
** Code external to the Vdbe then "borrows" the b-tree cursor and
** uses it to implement the blob_read(), blob_write() and
** blob_bytes() functions.
**
** The sqlite3_blob_close() function finalizes the vdbe program,
** which closes the b-tree cursor and (possibly) commits the
** transaction.
*/
static const VdbeOpList openBlob[] = {
{OP_Transaction, 0, 0, 0}, /* 0: Start a transaction */
{OP_VerifyCookie, 0, 0, 0}, /* 1: Check the schema cookie */
{OP_TableLock, 0, 0, 0}, /* 2: Acquire a read or write lock */
/* One of the following two instructions is replaced by an OP_Noop. */
{OP_OpenRead, 0, 0, 0}, /* 3: Open cursor 0 for reading */
{OP_OpenWrite, 0, 0, 0}, /* 4: Open cursor 0 for read/write */
{OP_Variable, 1, 1, 1}, /* 5: Push the rowid to the stack */
{OP_NotExists, 0, 9, 1}, /* 6: Seek the cursor */
{OP_Column, 0, 0, 1}, /* 7 */
{OP_ResultRow, 1, 0, 0}, /* 8 */
{OP_Close, 0, 0, 0}, /* 9 */
{OP_Halt, 0, 0, 0}, /* 10 */
};
Vdbe *v = 0;
int rc = SQLITE_OK;
char *zErr = 0;
Table *pTab;
Parse *pParse;
*ppBlob = 0;
sqlite3_mutex_enter(db->mutex);
pParse = sqlite3StackAllocRaw(db, sizeof(*pParse));
if( pParse==0 ){
rc = SQLITE_NOMEM;
goto blob_open_out;
}
do {
memset(pParse, 0, sizeof(Parse));
pParse->db = db;
if( sqlite3SafetyOn(db) ){
sqlite3DbFree(db, zErr);
sqlite3StackFree(db, pParse);
sqlite3_mutex_leave(db->mutex);
return SQLITE_MISUSE;
}
sqlite3BtreeEnterAll(db);
pTab = sqlite3LocateTable(pParse, 0, zTable, zDb);
if( pTab && IsVirtual(pTab) ){
pTab = 0;
sqlite3ErrorMsg(pParse, "cannot open virtual table: %s", zTable);
}
#ifndef SQLITE_OMIT_VIEW
if( pTab && pTab->pSelect ){
pTab = 0;
sqlite3ErrorMsg(pParse, "cannot open view: %s", zTable);
}
#endif
if( !pTab ){
if( pParse->zErrMsg ){
sqlite3DbFree(db, zErr);
zErr = pParse->zErrMsg;
pParse->zErrMsg = 0;
}
rc = SQLITE_ERROR;
(void)sqlite3SafetyOff(db);
sqlite3BtreeLeaveAll(db);
goto blob_open_out;
}
/* Now search pTab for the exact column. */
for(iCol=0; iCol < pTab->nCol; iCol++) {
if( sqlite3StrICmp(pTab->aCol[iCol].zName, zColumn)==0 ){
break;
}
}
if( iCol==pTab->nCol ){
sqlite3DbFree(db, zErr);
zErr = sqlite3MPrintf(db, "no such column: \"%s\"", zColumn);
rc = SQLITE_ERROR;
(void)sqlite3SafetyOff(db);
sqlite3BtreeLeaveAll(db);
goto blob_open_out;
}
/* If the value is being opened for writing, check that the
** column is not indexed. It is against the rules to open an
** indexed column for writing.
*/
if( flags ){
Index *pIdx;
for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
int j;
for(j=0; j<pIdx->nColumn; j++){
if( pIdx->aiColumn[j]==iCol ){
sqlite3DbFree(db, zErr);
zErr = sqlite3MPrintf(db,
"cannot open indexed column for writing");
rc = SQLITE_ERROR;
(void)sqlite3SafetyOff(db);
sqlite3BtreeLeaveAll(db);
goto blob_open_out;
}
}
}
}
v = sqlite3VdbeCreate(db);
if( v ){
int iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
sqlite3VdbeAddOpList(v, sizeof(openBlob)/sizeof(VdbeOpList), openBlob);
flags = !!flags; /* flags = (flags ? 1 : 0); */
/* Configure the OP_Transaction */
sqlite3VdbeChangeP1(v, 0, iDb);
sqlite3VdbeChangeP2(v, 0, flags);
/* Configure the OP_VerifyCookie */
sqlite3VdbeChangeP1(v, 1, iDb);
sqlite3VdbeChangeP2(v, 1, pTab->pSchema->schema_cookie);
/* Make sure a mutex is held on the table to be accessed */
sqlite3VdbeUsesBtree(v, iDb);
/* Configure the OP_TableLock instruction */
sqlite3VdbeChangeP1(v, 2, iDb);
sqlite3VdbeChangeP2(v, 2, pTab->tnum);
sqlite3VdbeChangeP3(v, 2, flags);
sqlite3VdbeChangeP4(v, 2, pTab->zName, P4_TRANSIENT);
/* Remove either the OP_OpenWrite or OpenRead. Set the P2
** parameter of the other to pTab->tnum. */
sqlite3VdbeChangeToNoop(v, 4 - flags, 1);
sqlite3VdbeChangeP2(v, 3 + flags, pTab->tnum);
sqlite3VdbeChangeP3(v, 3 + flags, iDb);
/* Configure the number of columns. Configure the cursor to
** think that the table has one more column than it really
** does. An OP_Column to retrieve this imaginary column will
** always return an SQL NULL. This is useful because it means
** we can invoke OP_Column to fill in the vdbe cursors type
** and offset cache without causing any IO.
*/
sqlite3VdbeChangeP4(v, 3+flags, SQLITE_INT_TO_PTR(pTab->nCol+1),P4_INT32);
sqlite3VdbeChangeP2(v, 7, pTab->nCol);
if( !db->mallocFailed ){
sqlite3VdbeMakeReady(v, 1, 1, 1, 0);
}
}
sqlite3BtreeLeaveAll(db);
rc = sqlite3SafetyOff(db);
if( NEVER(rc!=SQLITE_OK) || db->mallocFailed ){
goto blob_open_out;
}
sqlite3_bind_int64((sqlite3_stmt *)v, 1, iRow);
rc = sqlite3_step((sqlite3_stmt *)v);
if( rc!=SQLITE_ROW ){
nAttempt++;
rc = sqlite3_finalize((sqlite3_stmt *)v);
sqlite3DbFree(db, zErr);
zErr = sqlite3MPrintf(db, sqlite3_errmsg(db));
v = 0;
}
} while( nAttempt<5 && rc==SQLITE_SCHEMA );
if( rc==SQLITE_ROW ){
/* The row-record has been opened successfully. Check that the
** column in question contains text or a blob. If it contains
** text, it is up to the caller to get the encoding right.
*/
Incrblob *pBlob;
u32 type = v->apCsr[0]->aType[iCol];
if( type<12 ){
sqlite3DbFree(db, zErr);
zErr = sqlite3MPrintf(db, "cannot open value of type %s",
type==0?"null": type==7?"real": "integer"
);
rc = SQLITE_ERROR;
goto blob_open_out;
}
pBlob = (Incrblob *)sqlite3DbMallocZero(db, sizeof(Incrblob));
if( db->mallocFailed ){
sqlite3DbFree(db, pBlob);
goto blob_open_out;
}
pBlob->flags = flags;
pBlob->pCsr = v->apCsr[0]->pCursor;
sqlite3BtreeEnterCursor(pBlob->pCsr);
sqlite3BtreeCacheOverflow(pBlob->pCsr);
sqlite3BtreeLeaveCursor(pBlob->pCsr);
pBlob->pStmt = (sqlite3_stmt *)v;
pBlob->iOffset = v->apCsr[0]->aOffset[iCol];
pBlob->nByte = sqlite3VdbeSerialTypeLen(type);
pBlob->db = db;
*ppBlob = (sqlite3_blob *)pBlob;
rc = SQLITE_OK;
}else if( rc==SQLITE_OK ){
sqlite3DbFree(db, zErr);
zErr = sqlite3MPrintf(db, "no such rowid: %lld", iRow);
rc = SQLITE_ERROR;
}
blob_open_out:
if( v && (rc!=SQLITE_OK || db->mallocFailed) ){
sqlite3VdbeFinalize(v);
}
sqlite3Error(db, rc, zErr);
sqlite3DbFree(db, zErr);
sqlite3StackFree(db, pParse);
rc = sqlite3ApiExit(db, rc);
sqlite3_mutex_leave(db->mutex);
return rc;
}
/*
** Generate code to implement the "ALTER TABLE xxx RENAME TO yyy"
** command.
*/
void sqlite3AlterRenameTable(
Parse *pParse, /* Parser context. */
SrcList *pSrc, /* The table to rename. */
Token *pName /* The new table name. */
){
int iDb; /* Database that contains the table */
char *zDb; /* Name of database iDb */
Table *pTab; /* Table being renamed */
char *zName = 0; /* NULL-terminated version of pName */
sqlite3 *db = pParse->db; /* Database connection */
Vdbe *v;
#ifndef SQLITE_OMIT_TRIGGER
char *zWhere = 0; /* Where clause to locate temp triggers */
#endif
if( sqlite3_malloc_failed ) goto exit_rename_table;
assert( pSrc->nSrc==1 );
pTab = sqlite3LocateTable(pParse, pSrc->a[0].zName, pSrc->a[0].zDatabase);
if( !pTab ) goto exit_rename_table;
iDb = pTab->iDb;
zDb = db->aDb[iDb].zName;
/* Get a NULL terminated version of the new table name. */
zName = sqlite3NameFromToken(pName);
if( !zName ) goto exit_rename_table;
/* Check that a table or index named 'zName' does not already exist
** in database iDb. If so, this is an error.
*/
if( sqlite3FindTable(db, zName, zDb) || sqlite3FindIndex(db, zName, zDb) ){
sqlite3ErrorMsg(pParse,
"there is already another table or index with this name: %s", zName);
goto exit_rename_table;
}
/* Make sure it is not a system table being altered, or a reserved name
** that the table is being renamed to.
*/
if( strlen(pTab->zName)>6 && 0==sqlite3StrNICmp(pTab->zName, "sqlite_", 7) ){
sqlite3ErrorMsg(pParse, "table %s may not be altered", pTab->zName);
goto exit_rename_table;
}
if( SQLITE_OK!=sqlite3CheckObjectName(pParse, zName) ){
goto exit_rename_table;
}
#ifndef SQLITE_OMIT_AUTHORIZATION
/* Invoke the authorization callback. */
if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab->zName, 0) ){
goto exit_rename_table;
}
#endif
/* Begin a transaction and code the VerifyCookie for database iDb.
** Then modify the schema cookie (since the ALTER TABLE modifies the
** schema).
*/
v = sqlite3GetVdbe(pParse);
if( v==0 ){
goto exit_rename_table;
}
sqlite3BeginWriteOperation(pParse, 0, iDb);
sqlite3ChangeCookie(db, v, iDb);
/* Modify the sqlite_master table to use the new table name. */
sqlite3NestedParse(pParse,
"UPDATE %Q.%s SET "
#ifdef SQLITE_OMIT_TRIGGER
"sql = sqlite_rename_table(sql, %Q), "
#else
"sql = CASE "
"WHEN type = 'trigger' THEN sqlite_rename_trigger(sql, %Q)"
"ELSE sqlite_rename_table(sql, %Q) END, "
#endif
"tbl_name = %Q, "
"name = CASE "
"WHEN type='table' THEN %Q "
"WHEN name LIKE 'sqlite_autoindex%%' AND type='index' THEN "
"'sqlite_autoindex_' || %Q || substr(name, %d+18,10) "
"ELSE name END "
"WHERE tbl_name=%Q AND "
"(type='table' OR type='index' OR type='trigger');",
zDb, SCHEMA_TABLE(iDb), zName, zName, zName,
#ifndef SQLITE_OMIT_TRIGGER
zName,
#endif
zName, strlen(pTab->zName), pTab->zName
);
#ifndef SQLITE_OMIT_AUTOINCREMENT
/* If the sqlite_sequence table exists in this database, then update
** it with the new table name.
*/
if( sqlite3FindTable(db, "sqlite_sequence", zDb) ){
sqlite3NestedParse(pParse,
"UPDATE %Q.sqlite_sequence set name = %Q WHERE name = %Q",
zDb, zName, pTab->zName);
}
#endif
#ifndef SQLITE_OMIT_TRIGGER
/* If there are TEMP triggers on this table, modify the sqlite_temp_master
** table. Don't do this if the table being ALTERed is itself located in
** the temp database.
*/
if( (zWhere=whereTempTriggers(pParse, pTab)) ){
sqlite3NestedParse(pParse,
"UPDATE sqlite_temp_master SET "
"sql = sqlite_rename_trigger(sql, %Q), "
"tbl_name = %Q "
"WHERE %s;", zName, zName, zWhere);
sqliteFree(zWhere);
}
#endif
/* Drop and reload the internal table schema. */
reloadTableSchema(pParse, pTab, zName);
exit_rename_table:
sqlite3SrcListDelete(pSrc);
sqliteFree(zName);
}
/*
** Open a blob handle.
*/
int sqlite3_blob_open(
sqlite3* db, /* The database connection */
const char *zDb, /* The attached database containing the blob */
const char *zTable, /* The table containing the blob */
const char *zColumn, /* The column containing the blob */
sqlite_int64 iRow, /* The row containing the glob */
int flags, /* True -> read/write access, false -> read-only */
sqlite3_blob **ppBlob /* Handle for accessing the blob returned here */
){
int nAttempt = 0;
int iCol; /* Index of zColumn in row-record */
/* This VDBE program seeks a btree cursor to the identified
** db/table/row entry. The reason for using a vdbe program instead
** of writing code to use the b-tree layer directly is that the
** vdbe program will take advantage of the various transaction,
** locking and error handling infrastructure built into the vdbe.
**
** After seeking the cursor, the vdbe executes an OP_ResultRow.
** Code external to the Vdbe then "borrows" the b-tree cursor and
** uses it to implement the blob_read(), blob_write() and
** blob_bytes() functions.
**
** The sqlite3_blob_close() function finalizes the vdbe program,
** which closes the b-tree cursor and (possibly) commits the
** transaction.
*/
static const VdbeOpList openBlob[] = {
{OP_Transaction, 0, 0, 0}, /* 0: Start a transaction */
{OP_VerifyCookie, 0, 0, 0}, /* 1: Check the schema cookie */
{OP_TableLock, 0, 0, 0}, /* 2: Acquire a read or write lock */
/* One of the following two instructions is replaced by an OP_Noop. */
{OP_OpenRead, 0, 0, 0}, /* 3: Open cursor 0 for reading */
{OP_OpenWrite, 0, 0, 0}, /* 4: Open cursor 0 for read/write */
{OP_Variable, 1, 1, 1}, /* 5: Push the rowid to the stack */
{OP_NotExists, 0, 10, 1}, /* 6: Seek the cursor */
{OP_Column, 0, 0, 1}, /* 7 */
{OP_ResultRow, 1, 0, 0}, /* 8 */
{OP_Goto, 0, 5, 0}, /* 9 */
{OP_Close, 0, 0, 0}, /* 10 */
{OP_Halt, 0, 0, 0}, /* 11 */
};
int rc = SQLITE_OK;
char *zErr = 0;
Table *pTab;
Parse *pParse = 0;
Incrblob *pBlob = 0;
flags = !!flags; /* flags = (flags ? 1 : 0); */
*ppBlob = 0;
sqlite3_mutex_enter(db->mutex);
pBlob = (Incrblob *)sqlite3DbMallocZero(db, sizeof(Incrblob));
if( !pBlob ) goto blob_open_out;
pParse = sqlite3StackAllocRaw(db, sizeof(*pParse));
if( !pParse ) goto blob_open_out;
do {
memset(pParse, 0, sizeof(Parse));
pParse->db = db;
sqlite3DbFree(db, zErr);
zErr = 0;
sqlite3BtreeEnterAll(db);
pTab = sqlite3LocateTable(pParse, 0, zTable, zDb);
if( pTab && IsVirtual(pTab) ){
pTab = 0;
sqlite3ErrorMsg(pParse, "cannot open virtual table: %s", zTable);
}
#ifndef SQLITE_OMIT_VIEW
if( pTab && pTab->pSelect ){
pTab = 0;
sqlite3ErrorMsg(pParse, "cannot open view: %s", zTable);
}
#endif
if( !pTab ){
if( pParse->zErrMsg ){
sqlite3DbFree(db, zErr);
zErr = pParse->zErrMsg;
pParse->zErrMsg = 0;
}
rc = SQLITE_ERROR;
sqlite3BtreeLeaveAll(db);
goto blob_open_out;
}
/* Now search pTab for the exact column. */
for(iCol=0; iCol<pTab->nCol; iCol++) {
if( sqlite3StrICmp(pTab->aCol[iCol].zName, zColumn)==0 ){
break;
}
}
if( iCol==pTab->nCol ){
sqlite3DbFree(db, zErr);
zErr = sqlite3MPrintf(db, "no such column: \"%s\"", zColumn);
rc = SQLITE_ERROR;
sqlite3BtreeLeaveAll(db);
goto blob_open_out;
}
/* If the value is being opened for writing, check that the
** column is not indexed, and that it is not part of a foreign key.
** It is against the rules to open a column to which either of these
** descriptions applies for writing. */
if( flags ){
const char *zFault = 0;
Index *pIdx;
#ifndef SQLITE_OMIT_FOREIGN_KEY
if( db->flags&SQLITE_ForeignKeys ){
/* Check that the column is not part of an FK child key definition. It
** is not necessary to check if it is part of a parent key, as parent
** key columns must be indexed. The check below will pick up this
** case. */
FKey *pFKey;
for(pFKey=pTab->pFKey; pFKey; pFKey=pFKey->pNextFrom){
int j;
for(j=0; j<pFKey->nCol; j++){
if( pFKey->aCol[j].iFrom==iCol ){
zFault = "foreign key";
}
}
}
}
#endif
for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
int j;
for(j=0; j<pIdx->nColumn; j++){
if( pIdx->aiColumn[j]==iCol ){
zFault = "indexed";
}
}
}
if( zFault ){
sqlite3DbFree(db, zErr);
zErr = sqlite3MPrintf(db, "cannot open %s column for writing", zFault);
rc = SQLITE_ERROR;
sqlite3BtreeLeaveAll(db);
goto blob_open_out;
}
}
pBlob->pStmt = (sqlite3_stmt *)sqlite3VdbeCreate(db);
assert( pBlob->pStmt || db->mallocFailed );
if( pBlob->pStmt ){
Vdbe *v = (Vdbe *)pBlob->pStmt;
int iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
sqlite3VdbeAddOpList(v, sizeof(openBlob)/sizeof(VdbeOpList), openBlob);
/* Configure the OP_Transaction */
sqlite3VdbeChangeP1(v, 0, iDb);
sqlite3VdbeChangeP2(v, 0, flags);
/* Configure the OP_VerifyCookie */
sqlite3VdbeChangeP1(v, 1, iDb);
sqlite3VdbeChangeP2(v, 1, pTab->pSchema->schema_cookie);
sqlite3VdbeChangeP3(v, 1, pTab->pSchema->iGeneration);
/* Make sure a mutex is held on the table to be accessed */
sqlite3VdbeUsesBtree(v, iDb);
/* Configure the OP_TableLock instruction */
#ifdef SQLITE_OMIT_SHARED_CACHE
sqlite3VdbeChangeToNoop(v, 2);
#else
sqlite3VdbeChangeP1(v, 2, iDb);
sqlite3VdbeChangeP2(v, 2, pTab->tnum);
sqlite3VdbeChangeP3(v, 2, flags);
sqlite3VdbeChangeP4(v, 2, pTab->zName, P4_TRANSIENT);
#endif
/* Remove either the OP_OpenWrite or OpenRead. Set the P2
** parameter of the other to pTab->tnum. */
sqlite3VdbeChangeToNoop(v, 4 - flags);
sqlite3VdbeChangeP2(v, 3 + flags, pTab->tnum);
sqlite3VdbeChangeP3(v, 3 + flags, iDb);
/* Configure the number of columns. Configure the cursor to
** think that the table has one more column than it really
** does. An OP_Column to retrieve this imaginary column will
** always return an SQL NULL. This is useful because it means
** we can invoke OP_Column to fill in the vdbe cursors type
** and offset cache without causing any IO.
*/
sqlite3VdbeChangeP4(v, 3+flags, SQLITE_INT_TO_PTR(pTab->nCol+1),P4_INT32);
sqlite3VdbeChangeP2(v, 7, pTab->nCol);
if( !db->mallocFailed ){
pParse->nVar = 1;
pParse->nMem = 1;
pParse->nTab = 1;
sqlite3VdbeMakeReady(v, pParse);
}
}
pBlob->flags = flags;
pBlob->iCol = iCol;
pBlob->db = db;
sqlite3BtreeLeaveAll(db);
if( db->mallocFailed ){
goto blob_open_out;
}
sqlite3_bind_int64(pBlob->pStmt, 1, iRow);
rc = blobSeekToRow(pBlob, iRow, &zErr);
} while( (++nAttempt)<5 && rc==SQLITE_SCHEMA );
blob_open_out:
if( rc==SQLITE_OK && db->mallocFailed==0 ){
*ppBlob = (sqlite3_blob *)pBlob;
}else{
if( pBlob && pBlob->pStmt ) sqlite3VdbeFinalize((Vdbe *)pBlob->pStmt);
sqlite3DbFree(db, pBlob);
}
sqlite3Error(db, rc, (zErr ? "%s" : 0), zErr);
sqlite3DbFree(db, zErr);
sqlite3StackFree(db, pParse);
rc = sqlite3ApiExit(db, rc);
sqlite3_mutex_leave(db->mutex);
return rc;
}
/*
** Generate code to implement the "ALTER TABLE xxx RENAME TO yyy"
** command.
*/
void sqlite3AlterRenameTable(
Parse *pParse, /* Parser context. */
SrcList *pSrc, /* The table to rename. */
Token *pName /* The new table name. */
){
int iDb; /* Database that contains the table */
char *zDb; /* Name of database iDb */
Table *pTab; /* Table being renamed */
char *zName = 0; /* NULL-terminated version of pName */
sqlite3 *db = pParse->db; /* Database connection */
int nTabName; /* Number of UTF-8 characters in zTabName */
const char *zTabName; /* Original name of the table */
Vdbe *v;
#ifndef SQLITE_OMIT_TRIGGER
char *zWhere = 0; /* Where clause to locate temp triggers */
#endif
VTable *pVTab = 0; /* Non-zero if this is a v-tab with an xRename() */
int savedDbFlags; /* Saved value of db->flags */
savedDbFlags = db->flags;
if( NEVER(db->mallocFailed) ) goto exit_rename_table;
assert( pSrc->nSrc==1 );
assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
pTab = sqlite3LocateTable(pParse, 0, pSrc->a[0].zName, pSrc->a[0].zDatabase);
if( !pTab ) goto exit_rename_table;
iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
zDb = db->aDb[iDb].zName;
db->flags |= SQLITE_PreferBuiltin;
/* Get a NULL terminated version of the new table name. */
zName = sqlite3NameFromToken(db, pName);
if( !zName ) goto exit_rename_table;
/* Check that a table or index named 'zName' does not already exist
** in database iDb. If so, this is an error.
*/
if( sqlite3FindTable(db, zName, zDb) || sqlite3FindIndex(db, zName, zDb) ){
sqlite3ErrorMsg(pParse,
"there is already another table or index with this name: %s", zName);
goto exit_rename_table;
}
/* Make sure it is not a system table being altered, or a reserved name
** that the table is being renamed to.
*/
if( SQLITE_OK!=isSystemTable(pParse, pTab->zName) ){
goto exit_rename_table;
}
if( SQLITE_OK!=sqlite3CheckObjectName(pParse, zName) ){ goto
exit_rename_table;
}
#ifndef SQLITE_OMIT_VIEW
if( pTab->pSelect ){
sqlite3ErrorMsg(pParse, "view %s may not be altered", pTab->zName);
goto exit_rename_table;
}
#endif
#ifndef SQLITE_OMIT_AUTHORIZATION
/* Invoke the authorization callback. */
if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab->zName, 0) ){
goto exit_rename_table;
}
#endif
#ifndef SQLITE_OMIT_VIRTUALTABLE
if( sqlite3ViewGetColumnNames(pParse, pTab) ){
goto exit_rename_table;
}
if( IsVirtual(pTab) ){
pVTab = sqlite3GetVTable(db, pTab);
if( pVTab->pVtab->pModule->xRename==0 ){
pVTab = 0;
}
}
#endif
/* Begin a transaction and code the VerifyCookie for database iDb.
** Then modify the schema cookie (since the ALTER TABLE modifies the
** schema). Open a statement transaction if the table is a virtual
** table.
*/
v = sqlite3GetVdbe(pParse);
if( v==0 ){
goto exit_rename_table;
}
sqlite3BeginWriteOperation(pParse, pVTab!=0, iDb);
sqlite3ChangeCookie(pParse, iDb);
/* If this is a virtual table, invoke the xRename() function if
** one is defined. The xRename() callback will modify the names
** of any resources used by the v-table implementation (including other
** SQLite tables) that are identified by the name of the virtual table.
*/
#ifndef SQLITE_OMIT_VIRTUALTABLE
if( pVTab ){
int i = ++pParse->nMem;
sqlite3VdbeAddOp4(v, OP_String8, 0, i, 0, zName, 0);
sqlite3VdbeAddOp4(v, OP_VRename, i, 0, 0,(const char*)pVTab, P4_VTAB);
sqlite3MayAbort(pParse);
}
#endif
/* figure out how many UTF-8 characters are in zName */
zTabName = pTab->zName;
nTabName = sqlite3Utf8CharLen(zTabName, -1);
#if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
if( db->flags&SQLITE_ForeignKeys ){
/* If foreign-key support is enabled, rewrite the CREATE TABLE
** statements corresponding to all child tables of foreign key constraints
** for which the renamed table is the parent table. */
if( (zWhere=whereForeignKeys(pParse, pTab))!=0 ){
sqlite3NestedParse(pParse,
"UPDATE \"%w\".%s SET "
"sql = sqlite_rename_parent(sql, %Q, %Q) "
"WHERE %s;", zDb, SCHEMA_TABLE(iDb), zTabName, zName, zWhere);
sqlite3DbFree(db, zWhere);
}
}
#endif
/* Modify the sqlite_master table to use the new table name. */
sqlite3NestedParse(pParse,
"UPDATE %Q.%s SET "
#ifdef SQLITE_OMIT_TRIGGER
"sql = sqlite_rename_table(sql, %Q), "
#else
"sql = CASE "
"WHEN type = 'trigger' THEN sqlite_rename_trigger(sql, %Q)"
"ELSE sqlite_rename_table(sql, %Q) END, "
#endif
"tbl_name = %Q, "
"name = CASE "
"WHEN type='table' THEN %Q "
"WHEN name LIKE 'sqlite_autoindex%%' AND type='index' THEN "
"'sqlite_autoindex_' || %Q || substr(name,%d+18) "
"ELSE name END "
"WHERE tbl_name=%Q COLLATE nocase AND "
"(type='table' OR type='index' OR type='trigger');",
zDb, SCHEMA_TABLE(iDb), zName, zName, zName,
#ifndef SQLITE_OMIT_TRIGGER
zName,
#endif
zName, nTabName, zTabName
);
#ifndef SQLITE_OMIT_AUTOINCREMENT
/* If the sqlite_sequence table exists in this database, then update
** it with the new table name.
*/
if( sqlite3FindTable(db, "sqlite_sequence", zDb) ){
sqlite3NestedParse(pParse,
"UPDATE \"%w\".sqlite_sequence set name = %Q WHERE name = %Q",
zDb, zName, pTab->zName);
}
#endif
#ifndef SQLITE_OMIT_TRIGGER
/* If there are TEMP triggers on this table, modify the sqlite_temp_master
** table. Don't do this if the table being ALTERed is itself located in
** the temp database.
*/
if( (zWhere=whereTempTriggers(pParse, pTab))!=0 ){
sqlite3NestedParse(pParse,
"UPDATE sqlite_temp_master SET "
"sql = sqlite_rename_trigger(sql, %Q), "
"tbl_name = %Q "
"WHERE %s;", zName, zName, zWhere);
sqlite3DbFree(db, zWhere);
}
#endif
#if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
if( db->flags&SQLITE_ForeignKeys ){
FKey *p;
for(p=sqlite3FkReferences(pTab); p; p=p->pNextTo){
Table *pFrom = p->pFrom;
if( pFrom!=pTab ){
reloadTableSchema(pParse, p->pFrom, pFrom->zName);
}
}
}
#endif
/* Drop and reload the internal table schema. */
reloadTableSchema(pParse, pTab, zName);
exit_rename_table:
sqlite3SrcListDelete(db, pSrc);
sqlite3DbFree(db, zName);
db->flags = savedDbFlags;
}
/*
** This function is called when inserting, deleting or updating a row of
** table pTab to generate VDBE code to perform foreign key constraint
** processing for the operation.
**
** For a DELETE operation, parameter regOld is passed the index of the
** first register in an array of (pTab->nCol+1) registers containing the
** rowid of the row being deleted, followed by each of the column values
** of the row being deleted, from left to right. Parameter regNew is passed
** zero in this case.
**
** For an INSERT operation, regOld is passed zero and regNew is passed the
** first register of an array of (pTab->nCol+1) registers containing the new
** row data.
**
** For an UPDATE operation, this function is called twice. Once before
** the original record is deleted from the table using the calling convention
** described for DELETE. Then again after the original record is deleted
** but before the new record is inserted using the INSERT convention.
*/
void sqlite3FkCheck(
Parse *pParse, /* Parse context */
Table *pTab, /* Row is being deleted from this table */
int regOld, /* Previous row data is stored here */
int regNew /* New row data is stored here */
){
sqlite3 *db = pParse->db; /* Database handle */
FKey *pFKey; /* Used to iterate through FKs */
int iDb; /* Index of database containing pTab */
const char *zDb; /* Name of database containing pTab */
int isIgnoreErrors = pParse->disableTriggers;
/* Exactly one of regOld and regNew should be non-zero. */
assert( (regOld==0)!=(regNew==0) );
/* If foreign-keys are disabled, this function is a no-op. */
if( (db->flags&SQLITE_ForeignKeys)==0 ) return;
iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
zDb = db->aDb[iDb].zName;
/* Loop through all the foreign key constraints for which pTab is the
** child table (the table that the foreign key definition is part of). */
for(pFKey=pTab->pFKey; pFKey; pFKey=pFKey->pNextFrom){
Table *pTo; /* Parent table of foreign key pFKey */
Index *pIdx = 0; /* Index on key columns in pTo */
int *aiFree = 0;
int *aiCol;
int iCol;
int i;
int isIgnore = 0;
/* Find the parent table of this foreign key. Also find a unique index
** on the parent key columns in the parent table. If either of these
** schema items cannot be located, set an error in pParse and return
** early. */
if( pParse->disableTriggers ){
pTo = sqlite3FindTable(db, pFKey->zTo, zDb);
}else{
pTo = sqlite3LocateTable(pParse, 0, pFKey->zTo, zDb);
}
if( !pTo || locateFkeyIndex(pParse, pTo, pFKey, &pIdx, &aiFree) ){
assert( isIgnoreErrors==0 || (regOld!=0 && regNew==0) );
if( !isIgnoreErrors || db->mallocFailed ) return;
if( pTo==0 ){
/* If isIgnoreErrors is true, then a table is being dropped. In this
** case SQLite runs a "DELETE FROM xxx" on the table being dropped
** before actually dropping it in order to check FK constraints.
** If the parent table of an FK constraint on the current table is
** missing, behave as if it is empty. i.e. decrement the relevant
** FK counter for each row of the current table with non-NULL keys.
*/
Vdbe *v = sqlite3GetVdbe(pParse);
int iJump = sqlite3VdbeCurrentAddr(v) + pFKey->nCol + 1;
for(i=0; i<pFKey->nCol; i++){
int iReg = pFKey->aCol[i].iFrom + regOld + 1;
sqlite3VdbeAddOp2(v, OP_IsNull, iReg, iJump);
}
sqlite3VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, -1);
}
continue;
}
assert( pFKey->nCol==1 || (aiFree && pIdx) );
if( aiFree ){
aiCol = aiFree;
}else{
iCol = pFKey->aCol[0].iFrom;
aiCol = &iCol;
}
for(i=0; i<pFKey->nCol; i++){
if( aiCol[i]==pTab->iPKey ){
aiCol[i] = -1;
}
#ifndef SQLITE_OMIT_AUTHORIZATION
/* Request permission to read the parent key columns. If the
** authorization callback returns SQLITE_IGNORE, behave as if any
** values read from the parent table are NULL. */
if( db->xAuth ){
int rcauth;
char *zCol = pTo->aCol[pIdx ? pIdx->aiColumn[i] : pTo->iPKey].zName;
rcauth = sqlite3AuthReadCol(pParse, pTo->zName, zCol, iDb);
isIgnore = (rcauth==SQLITE_IGNORE);
}
#endif
}
/* Take a shared-cache advisory read-lock on the parent table. Allocate
** a cursor to use to search the unique index on the parent key columns
** in the parent table. */
sqlite3TableLock(pParse, iDb, pTo->tnum, 0, pTo->zName);
pParse->nTab++;
if( regOld!=0 ){
/* A row is being removed from the child table. Search for the parent.
** If the parent does not exist, removing the child row resolves an
** outstanding foreign key constraint violation. */
fkLookupParent(pParse, iDb, pTo, pIdx, pFKey, aiCol, regOld, -1,isIgnore);
}
if( regNew!=0 ){
/* A row is being added to the child table. If a parent row cannot
** be found, adding the child row has violated the FK constraint. */
fkLookupParent(pParse, iDb, pTo, pIdx, pFKey, aiCol, regNew, +1,isIgnore);
}
sqlite3DbFree(db, aiFree);
}
/* Loop through all the foreign key constraints that refer to this table */
for(pFKey = sqlite3FkReferences(pTab); pFKey; pFKey=pFKey->pNextTo){
Index *pIdx = 0; /* Foreign key index for pFKey */
SrcList *pSrc;
int *aiCol = 0;
if( !pFKey->isDeferred && !pParse->pToplevel && !pParse->isMultiWrite ){
assert( regOld==0 && regNew!=0 );
/* Inserting a single row into a parent table cannot cause an immediate
** foreign key violation. So do nothing in this case. */
continue;
}
if( locateFkeyIndex(pParse, pTab, pFKey, &pIdx, &aiCol) ){
if( !isIgnoreErrors || db->mallocFailed ) return;
continue;
}
assert( aiCol || pFKey->nCol==1 );
/* Create a SrcList structure containing a single table (the table
** the foreign key that refers to this table is attached to). This
** is required for the sqlite3WhereXXX() interface. */
pSrc = sqlite3SrcListAppend(db, 0, 0, 0);
if( pSrc ){
struct SrcList_item *pItem = pSrc->a;
pItem->pTab = pFKey->pFrom;
pItem->zName = pFKey->pFrom->zName;
pItem->pTab->nRef++;
pItem->iCursor = pParse->nTab++;
if( regNew!=0 ){
fkScanChildren(pParse, pSrc, pTab, pIdx, pFKey, aiCol, regNew, -1);
}
if( regOld!=0 ){
/* If there is a RESTRICT action configured for the current operation
** on the parent table of this FK, then throw an exception
** immediately if the FK constraint is violated, even if this is a
** deferred trigger. That's what RESTRICT means. To defer checking
** the constraint, the FK should specify NO ACTION (represented
** using OE_None). NO ACTION is the default. */
fkScanChildren(pParse, pSrc, pTab, pIdx, pFKey, aiCol, regOld, 1);
}
pItem->zName = 0;
sqlite3SrcListDelete(db, pSrc);
}
sqlite3DbFree(db, aiCol);
}
}
/*
** Generate code to implement the "ALTER TABLE xxx RENAME TO yyy"
** command. 生成代码来实现“ALTER TABLE xxx重命名yyy”命令。
*/
void sqlite3AlterRenameTable(
Parse *pParse, /* Parser context. 语法分析器上下文*/
SrcList *pSrc, /* The table to rename. 重命名的表*/
Token *pName /* The new table name. 新表名*/
){
int iDb; /* Database that contains the table 包含表的数据库*/
char *zDb; /* Name of database iDb 数据库iDb 的名称*/
Table *pTab; /* Table being renamed 正在重命名的表*/
char *zName = 0; /* NULL-terminated version of pName pName的空值终止版本*/
sqlite3 *db = pParse->db; /* Database connection 数据库的连接*/
int nTabName; /* Number of UTF-8 characters in zTabName 在 zTabName里的UTF-8类型的数目*/
const char *zTabName; /* Original name of the table 最初的数据库名称*/
Vdbe *v;
#ifndef SQLITE_OMIT_TRIGGER
char *zWhere = 0; /* Where clause to locate temp triggers Where 子句位于temp触发器*/
#endif
VTable *pVTab = 0; /* Non-zero if this is a v-tab with an xRename() 如果是 一个v-tab 和一个xRename() ，则为零*/
int savedDbFlags; /* Saved value of db->flags db->flags的保留值*/
savedDbFlags = db->flags;
if( NEVER(db->mallocFailed) ) goto exit_rename_table;
assert( pSrc->nSrc==1 );
assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
pTab = sqlite3LocateTable(pParse, 0, pSrc->a[0].zName, pSrc->a[0].zDatabase);
if( !pTab ) goto exit_rename_table;
iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
zDb = db->aDb[iDb].zName;
db->flags |= SQLITE_PreferBuiltin;
/* Get a NULL terminated version of the new table name. 得到一个空终止版本的新表的名称。*/
zName = sqlite3NameFromToken(db, pName);
if( !zName ) goto exit_rename_table;
/* Check that a table or index named 'zName' does not already exist
** in database iDb. If so, this is an error.检查一个表或索引名叫“zName”不存在数据库iDb。
如果是这样,这是一个错误。
*/
if( sqlite3FindTable(db, zName, zDb) || sqlite3FindIndex(db, zName, zDb) ){
sqlite3ErrorMsg(pParse,
"there is already another table or index with this name: %s", zName);
goto exit_rename_table;
}
/* Make sure it is not a system table being altered, or a reserved name
** that the table is being renamed to.
确保它不是一个正在被修改的系统表或者一个正在被重命名的保留的名称表
*/
if( SQLITE_OK!=isSystemTable(pParse, pTab->zName) ){
goto exit_rename_table;
}
if( SQLITE_OK!=sqlite3CheckObjectName(pParse, zName) ){ goto
exit_rename_table;
}
#ifndef SQLITE_OMIT_VIEW
if( pTab->pSelect ){
sqlite3ErrorMsg(pParse, "view %s may not be altered", pTab->zName);
goto exit_rename_table;
}
#endif
#ifndef SQLITE_OMIT_AUTHORIZATION
/* Invoke the authorization callback. 调用授权回调。*/
if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab->zName, 0) ){
goto exit_rename_table;
}
#endif
#ifndef SQLITE_OMIT_VIRTUALTABLE
if( sqlite3ViewGetColumnNames(pParse, pTab) ){
goto exit_rename_table;
}
if( IsVirtual(pTab) ){
pVTab = sqlite3GetVTable(db, pTab);
if( pVTab->pVtab->pModule->xRename==0 ){
pVTab = 0;
}
}
#endif
/* Begin a transaction and code the VerifyCookie for database iDb.
** Then modify the schema cookie (since the ALTER TABLE modifies the
** schema). Open a statement transaction if the table is a virtual
** table.
对于iDb数据库开始一个事务和代码的VerifyCookie。
然后修改模式cookie(因为ALTER TABLE修改模式)。
如果表是一个虚拟表打开一个声明事务。
*/
v = sqlite3GetVdbe(pParse);
if( v==0 ){
goto exit_rename_table;
}
sqlite3BeginWriteOperation(pParse, pVTab!=0, iDb);
sqlite3ChangeCookie(pParse, iDb);
/* If this is a virtual table, invoke the xRename() function if
** one is defined. The xRename() callback will modify the names
** of any resources used by the v-table implementation (including other
** SQLite tables) that are identified by the name of the virtual table.、
如果这是一个虚拟表,调用xRename()函数如果一个定义。
xRename()回调将修改使用v-table实现的任何资源的名字(包括其他SQLite表)，
这个v-table实现是确定的虚拟表的名称。
*/
#ifndef SQLITE_OMIT_VIRTUALTABLE
if( pVTab ){
int i = ++pParse->nMem;
sqlite3VdbeAddOp4(v, OP_String8, 0, i, 0, zName, 0);
sqlite3VdbeAddOp4(v, OP_VRename, i, 0, 0,(const char*)pVTab, P4_VTAB);
sqlite3MayAbort(pParse);
}
#endif
/* figure out how many UTF-8 characters are in zName 算出在zName里有多少utf - 8字符*/
zTabName = pTab->zName;
nTabName = sqlite3Utf8CharLen(zTabName, -1);
#if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
if( db->flags&SQLITE_ForeignKeys ){
/* If foreign-key support is enabled, rewrite the CREATE TABLE
** statements corresponding to all child tables of foreign key constraints
** for which the renamed table is the parent table.
如果启用了外键的支持,重写CREATE TABLE语句对应的所有子表的外键约束重命名表的父表。*/
if( (zWhere=whereForeignKeys(pParse, pTab))!=0 ){
sqlite3NestedParse(pParse,
"UPDATE \"%w\".%s SET "
"sql = sqlite_rename_parent(sql, %Q, %Q) "
"WHERE %s;", zDb, SCHEMA_TABLE(iDb), zTabName, zName, zWhere);
sqlite3DbFree(db, zWhere);
}
}
#endif
/* Modify the sqlite_master table to use the new table name. 修改sqlite_master表来使用新的表名。*/
sqlite3NestedParse(pParse,
"UPDATE %Q.%s SET "
#ifdef SQLITE_OMIT_TRIGGER
"sql = sqlite_rename_table(sql, %Q), "
#else
"sql = CASE "
"WHEN type = 'trigger' THEN sqlite_rename_trigger(sql, %Q)"
"ELSE sqlite_rename_table(sql, %Q) END, "
#endif
"tbl_name = %Q, "
"name = CASE "
"WHEN type='table' THEN %Q "
"WHEN name LIKE 'sqlite_autoindex%%' AND type='index' THEN "
"'sqlite_autoindex_' || %Q || substr(name,%d+18) "
"ELSE name END "
"WHERE tbl_name=%Q COLLATE nocase AND "
"(type='table' OR type='index' OR type='trigger');",
zDb, SCHEMA_TABLE(iDb), zName, zName, zName,
#ifndef SQLITE_OMIT_TRIGGER
zName,
#endif
zName, nTabName, zTabName
);
#ifndef SQLITE_OMIT_AUTOINCREMENT
/* If the sqlite_sequence table exists in this database, then update
** it with the new table name.
如果sqlite_sequence表存在于这个数据库中,那么用新表的名称更新它
*/
if( sqlite3FindTable(db, "sqlite_sequence", zDb) ){
sqlite3NestedParse(pParse,
"UPDATE \"%w\".sqlite_sequence set name = %Q WHERE name = %Q",
zDb, zName, pTab->zName);
}
#endif
#ifndef SQLITE_OMIT_TRIGGER
/* If there are TEMP triggers on this table, modify the sqlite_temp_master
** table. Don't do this if the table being ALTERed is itself located in
** the temp database.
如果在这个表上有临时触发器，修改sqlite_temp_master表，
如果表被修改本身就是位于临时数据库，不要做这些。
*/
if( (zWhere=whereTempTriggers(pParse, pTab))!=0 ){
sqlite3NestedParse(pParse,
"UPDATE sqlite_temp_master SET "
"sql = sqlite_rename_trigger(sql, %Q), "
"tbl_name = %Q "
"WHERE %s;", zName, zName, zWhere);
sqlite3DbFree(db, zWhere);
}
#endif
#if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
if( db->flags&SQLITE_ForeignKeys ){
FKey *p;
for(p=sqlite3FkReferences(pTab); p; p=p->pNextTo){
Table *pFrom = p->pFrom;
if( pFrom!=pTab ){
reloadTableSchema(pParse, p->pFrom, pFrom->zName);
}
}
}
#endif
/* Drop and reload the internal table schema. 删除和重新加载内部表模式。*/
reloadTableSchema(pParse, pTab, zName);
exit_rename_table:
sqlite3SrcListDelete(db, pSrc);
sqlite3DbFree(db, zName);
db->flags = savedDbFlags;
}
/*
** This routine is called after all of the trigger actions have been parsed
** in order to complete the process of building the trigger.
*/
void sqlite3FinishTrigger(
Parse *pParse, /* Parser context */
TriggerStep *pStepList, /* The triggered program */
Token *pAll /* Token that describes the complete CREATE TRIGGER */
){
Trigger *pTrig = 0; /* The trigger whose construction is finishing up */
sqlite3 *db = pParse->db; /* The database */
DbFixer sFix;
pTrig = pParse->pNewTrigger;
pParse->pNewTrigger = 0;
if( pParse->nErr || pTrig==0 ) goto triggerfinish_cleanup;
pTrig->step_list = pStepList;
while( pStepList ){
pStepList->pTrig = pTrig;
pStepList = pStepList->pNext;
}
if( sqlite3FixInit(&sFix, pParse, pTrig->iDb, "trigger", &pTrig->nameToken)
&& sqlite3FixTriggerStep(&sFix, pTrig->step_list) ){
goto triggerfinish_cleanup;
}
/* if we are not initializing, and this trigger is not on a TEMP table,
** build the sqlite_master entry
*/
if( !db->init.busy ){
static const VdbeOpList insertTrig[] = {
{ OP_NewRecno, 0, 0, 0 },
{ OP_String8, 0, 0, "trigger" },
{ OP_String8, 0, 0, 0 }, /* 2: trigger name */
{ OP_String8, 0, 0, 0 }, /* 3: table name */
{ OP_Integer, 0, 0, 0 },
{ OP_String8, 0, 0, "CREATE TRIGGER "},
{ OP_String8, 0, 0, 0 }, /* 6: SQL */
{ OP_Concat, 0, 0, 0 },
{ OP_MakeRecord, 5, 0, "tttit" },
{ OP_PutIntKey, 0, 0, 0 },
};
int addr;
Vdbe *v;
/* Make an entry in the sqlite_master table */
v = sqlite3GetVdbe(pParse);
if( v==0 ) goto triggerfinish_cleanup;
sqlite3BeginWriteOperation(pParse, 0, pTrig->iDb);
sqlite3OpenMasterTable(v, pTrig->iDb);
addr = sqlite3VdbeAddOpList(v, ArraySize(insertTrig), insertTrig);
sqlite3VdbeChangeP3(v, addr+2, pTrig->name, 0);
sqlite3VdbeChangeP3(v, addr+3, pTrig->table, 0);
sqlite3VdbeChangeP3(v, addr+6, (const char*)pAll->z, pAll->n);
sqlite3ChangeCookie(db, v, pTrig->iDb);
sqlite3VdbeAddOp(v, OP_Close, 0, 0);
sqlite3VdbeOp3(v, OP_ParseSchema, pTrig->iDb, 0,
sqlite3MPrintf("type='trigger' AND name='%q'", pTrig->name), P3_DYNAMIC);
}
if( db->init.busy ){
Table *pTab;
Trigger *pDel;
pDel = (Trigger*)sqlite3HashInsert(&db->aDb[pTrig->iDb].trigHash,
pTrig->name, strlen(pTrig->name)+1, pTrig);
if( pDel ){
assert( sqlite3_malloc_failed && pDel==pTrig );
goto triggerfinish_cleanup;
}
pTab = sqlite3LocateTable(pParse,pTrig->table,db->aDb[pTrig->iTabDb].zName);
assert( pTab!=0 );
pTrig->pNext = pTab->pTrigger;
pTab->pTrigger = pTrig;
pTrig = 0;
}
triggerfinish_cleanup:
sqlite3DeleteTrigger(pTrig);
assert( !pParse->pNewTrigger );
sqlite3DeleteTriggerStep(pStepList);
}
