/*
** This routine is call to handle SQL of the following forms:
**
** insert into TABLE (IDLIST) values(EXPRLIST)
** insert into TABLE (IDLIST) select
**
** The IDLIST following the table name is always optional. If omitted,
** then a list of all columns for the table is substituted. The IDLIST
** appears in the pColumn parameter. pColumn is NULL if IDLIST is omitted.
**
** The pList parameter holds EXPRLIST in the first form of the INSERT
** statement above, and pSelect is NULL. For the second form, pList is
** NULL and pSelect is a pointer to the select statement used to generate
** data for the insert.
**
** The code generated follows one of three templates. For a simple
** select with data coming from a VALUES clause, the code executes
** once straight down through. The template looks like this:
**
** open write cursor to <table> and its indices
** puts VALUES clause expressions onto the stack
** write the resulting record into <table>
** cleanup
**
** If the statement is of the form
**
** INSERT INTO <table> SELECT ...
**
** And the SELECT clause does not read from <table> at any time, then
** the generated code follows this template:
**
** goto B
** A: setup for the SELECT
** loop over the tables in the SELECT
** gosub C
** end loop
** cleanup after the SELECT
** goto D
** B: open write cursor to <table> and its indices
** goto A
** C: insert the select result into <table>
** return
** D: cleanup
**
** The third template is used if the insert statement takes its
** values from a SELECT but the data is being inserted into a table
** that is also read as part of the SELECT. In the third form,
** we have to use a intermediate table to store the results of
** the select. The template is like this:
**
** goto B
** A: setup for the SELECT
** loop over the tables in the SELECT
** gosub C
** end loop
** cleanup after the SELECT
** goto D
** C: insert the select result into the intermediate table
** return
** B: open a cursor to an intermediate table
** goto A
** D: open write cursor to <table> and its indices
** loop over the intermediate table
** transfer values form intermediate table into <table>
** end the loop
** cleanup
*/
void sqlite3Insert(
Parse *pParse, /* Parser context */
SrcList *pTabList, /* Name of table into which we are inserting */
ExprList *pList, /* List of values to be inserted */
Select *pSelect, /* A SELECT statement to use as the data source */
IdList *pColumn, /* Column names corresponding to IDLIST. */
int onError /* How to handle constraint errors */
){
Table *pTab; /* The table to insert into */
char *zTab; /* Name of the table into which we are inserting */
const char *zDb; /* Name of the database holding this table */
int i, j, idx; /* Loop counters */
Vdbe *v; /* Generate code into this virtual machine */
Index *pIdx; /* For looping over indices of the table */
int nColumn; /* Number of columns in the data */
int base = 0; /* VDBE Cursor number for pTab */
int iCont=0,iBreak=0; /* Beginning and end of the loop over srcTab */
sqlite3 *db; /* The main database structure */
int keyColumn = -1; /* Column that is the INTEGER PRIMARY KEY */
int endOfLoop; /* Label for the end of the insertion loop */
int useTempTable; /* Store SELECT results in intermediate table */
int srcTab = 0; /* Data comes from this temporary cursor if >=0 */
int iSelectLoop = 0; /* Address of code that implements the SELECT */
int iCleanup = 0; /* Address of the cleanup code */
int iInsertBlock = 0; /* Address of the subroutine used to insert data */
int iCntMem = 0; /* Memory cell used for the row counter */
int isView; /* True if attempting to insert into a view */
int row_triggers_exist = 0; /* True if there are FOR EACH ROW triggers */
int before_triggers; /* True if there are BEFORE triggers */
int after_triggers; /* True if there are AFTER triggers */
int newIdx = -1; /* Cursor for the NEW table */
if( pParse->nErr || sqlite3_malloc_failed ) goto insert_cleanup;
db = pParse->db;
/* Locate the table into which we will be inserting new information.
*/
assert( pTabList->nSrc==1 );
zTab = pTabList->a[0].zName;
if( zTab==0 ) goto insert_cleanup;
pTab = sqlite3SrcListLookup(pParse, pTabList);
if( pTab==0 ){
goto insert_cleanup;
}
assert( pTab->iDb<db->nDb );
zDb = db->aDb[pTab->iDb].zName;
if( sqlite3AuthCheck(pParse, SQLITE_INSERT, pTab->zName, 0, zDb) ){
goto insert_cleanup;
}
/* Ensure that:
* (a) the table is not read-only,
* (b) that if it is a view then ON INSERT triggers exist
*/
before_triggers = sqlite3TriggersExist(pParse, pTab->pTrigger, TK_INSERT,
TK_BEFORE, TK_ROW, 0);
after_triggers = sqlite3TriggersExist(pParse, pTab->pTrigger, TK_INSERT,
TK_AFTER, TK_ROW, 0);
row_triggers_exist = before_triggers || after_triggers;
isView = pTab->pSelect!=0;
if( sqlite3IsReadOnly(pParse, pTab, before_triggers) ){
goto insert_cleanup;
}
if( pTab==0 ) goto insert_cleanup;
/* If pTab is really a view, make sure it has been initialized.
*/
if( isView && sqlite3ViewGetColumnNames(pParse, pTab) ){
goto insert_cleanup;
}
/* Ensure all required collation sequences are available. */
for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
if( sqlite3CheckIndexCollSeq(pParse, pIdx) ){
goto insert_cleanup;
}
}
/* Allocate a VDBE
*/
v = sqlite3GetVdbe(pParse);
if( v==0 ) goto insert_cleanup;
sqlite3VdbeCountChanges(v);
sqlite3BeginWriteOperation(pParse, pSelect || row_triggers_exist, pTab->iDb);
/* if there are row triggers, allocate a temp table for new.* references. */
if( row_triggers_exist ){
newIdx = pParse->nTab++;
}
/* Figure out how many columns of data are supplied. If the data
** is coming from a SELECT statement, then this step also generates
** all the code to implement the SELECT statement and invoke a subroutine
** to process each row of the result. (Template 2.) If the SELECT
** statement uses the the table that is being inserted into, then the
** subroutine is also coded here. That subroutine stores the SELECT
** results in a temporary table. (Template 3.)
*/
if( pSelect ){
/* Data is coming from a SELECT. Generate code to implement that SELECT
*/
int rc, iInitCode;
iInitCode = sqlite3VdbeAddOp(v, OP_Goto, 0, 0);
iSelectLoop = sqlite3VdbeCurrentAddr(v);
iInsertBlock = sqlite3VdbeMakeLabel(v);
rc = sqlite3Select(pParse, pSelect, SRT_Subroutine, iInsertBlock, 0,0,0,0);
if( rc || pParse->nErr || sqlite3_malloc_failed ) goto insert_cleanup;
iCleanup = sqlite3VdbeMakeLabel(v);
sqlite3VdbeAddOp(v, OP_Goto, 0, iCleanup);
assert( pSelect->pEList );
nColumn = pSelect->pEList->nExpr;
/* Set useTempTable to TRUE if the result of the SELECT statement
** should be written into a temporary table. Set to FALSE if each
** row of the SELECT can be written directly into the result table.
**
** A temp table must be used if the table being updated is also one
** of the tables being read by the SELECT statement. Also use a
** temp table in the case of row triggers.
*/
if( row_triggers_exist ){
useTempTable = 1;
}else{
int addr = 0;
useTempTable = 0;
while( useTempTable==0 ){
VdbeOp *pOp;
addr = sqlite3VdbeFindOp(v, addr, OP_OpenRead, pTab->tnum);
if( addr==0 ) break;
pOp = sqlite3VdbeGetOp(v, addr-2);
if( pOp->opcode==OP_Integer && pOp->p1==pTab->iDb ){
useTempTable = 1;
}
}
}
if( useTempTable ){
/* Generate the subroutine that SELECT calls to process each row of
** the result. Store the result in a temporary table
*/
srcTab = pParse->nTab++;
sqlite3VdbeResolveLabel(v, iInsertBlock);
sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
sqlite3TableAffinityStr(v, pTab);
sqlite3VdbeAddOp(v, OP_NewRecno, srcTab, 0);
sqlite3VdbeAddOp(v, OP_Pull, 1, 0);
sqlite3VdbeAddOp(v, OP_PutIntKey, srcTab, 0);
sqlite3VdbeAddOp(v, OP_Return, 0, 0);
/* The following code runs first because the GOTO at the very top
** of the program jumps to it. Create the temporary table, then jump
** back up and execute the SELECT code above.
*/
sqlite3VdbeChangeP2(v, iInitCode, sqlite3VdbeCurrentAddr(v));
sqlite3VdbeAddOp(v, OP_OpenTemp, srcTab, 0);
sqlite3VdbeAddOp(v, OP_SetNumColumns, srcTab, nColumn);
sqlite3VdbeAddOp(v, OP_Goto, 0, iSelectLoop);
sqlite3VdbeResolveLabel(v, iCleanup);
}else{
sqlite3VdbeChangeP2(v, iInitCode, sqlite3VdbeCurrentAddr(v));
}
}else{
/* This is the case if the data for the INSERT is coming from a VALUES
** clause
*/
SrcList dummy;
assert( pList!=0 );
srcTab = -1;
useTempTable = 0;
assert( pList );
nColumn = pList->nExpr;
dummy.nSrc = 0;
for(i=0; i<nColumn; i++){
if( sqlite3ExprResolveAndCheck(pParse,&dummy,0,pList->a[i].pExpr,0,0) ){
goto insert_cleanup;
}
}
}
/* Make sure the number of columns in the source data matches the number
** of columns to be inserted into the table.
*/
if( pColumn==0 && nColumn!=pTab->nCol ){
sqlite3ErrorMsg(pParse,
"table %S has %d columns but %d values were supplied",
pTabList, 0, pTab->nCol, nColumn);
goto insert_cleanup;
}
if( pColumn!=0 && nColumn!=pColumn->nId ){
sqlite3ErrorMsg(pParse, "%d values for %d columns", nColumn, pColumn->nId);
goto insert_cleanup;
}
/* If the INSERT statement included an IDLIST term, then make sure
** all elements of the IDLIST really are columns of the table and
** remember the column indices.
**
** If the table has an INTEGER PRIMARY KEY column and that column
** is named in the IDLIST, then record in the keyColumn variable
** the index into IDLIST of the primary key column. keyColumn is
** the index of the primary key as it appears in IDLIST, not as
** is appears in the original table. (The index of the primary
** key in the original table is pTab->iPKey.)
*/
if( pColumn ){
for(i=0; i<pColumn->nId; i++){
pColumn->a[i].idx = -1;
}
for(i=0; i<pColumn->nId; i++){
for(j=0; j<pTab->nCol; j++){
if( sqlite3StrICmp(pColumn->a[i].zName, pTab->aCol[j].zName)==0 ){
pColumn->a[i].idx = j;
if( j==pTab->iPKey ){
keyColumn = i;
}
break;
}
}
if( j>=pTab->nCol ){
if( sqlite3IsRowid(pColumn->a[i].zName) ){
keyColumn = i;
}else{
sqlite3ErrorMsg(pParse, "table %S has no column named %s",
pTabList, 0, pColumn->a[i].zName);
pParse->nErr++;
goto insert_cleanup;
}
}
}
}
/* If there is no IDLIST term but the table has an integer primary
** key, the set the keyColumn variable to the primary key column index
** in the original table definition.
*/
if( pColumn==0 ){
keyColumn = pTab->iPKey;
}
/* Open the temp table for FOR EACH ROW triggers
*/
if( row_triggers_exist ){
sqlite3VdbeAddOp(v, OP_OpenPseudo, newIdx, 0);
sqlite3VdbeAddOp(v, OP_SetNumColumns, newIdx, pTab->nCol);
}
/* Initialize the count of rows to be inserted
*/
if( db->flags & SQLITE_CountRows ){
iCntMem = pParse->nMem++;
sqlite3VdbeAddOp(v, OP_Integer, 0, 0);
sqlite3VdbeAddOp(v, OP_MemStore, iCntMem, 1);
}
/* Open tables and indices if there are no row triggers */
if( !row_triggers_exist ){
base = pParse->nTab;
sqlite3OpenTableAndIndices(pParse, pTab, base, OP_OpenWrite);
}
/* If the data source is a temporary table, then we have to create
** a loop because there might be multiple rows of data. If the data
** source is a subroutine call from the SELECT statement, then we need
** to launch the SELECT statement processing.
*/
if( useTempTable ){
iBreak = sqlite3VdbeMakeLabel(v);
sqlite3VdbeAddOp(v, OP_Rewind, srcTab, iBreak);
iCont = sqlite3VdbeCurrentAddr(v);
}else if( pSelect ){
sqlite3VdbeAddOp(v, OP_Goto, 0, iSelectLoop);
sqlite3VdbeResolveLabel(v, iInsertBlock);
}
/* Run the BEFORE and INSTEAD OF triggers, if there are any
*/
endOfLoop = sqlite3VdbeMakeLabel(v);
if( before_triggers ){
/* build the NEW.* reference row. Note that if there is an INTEGER
** PRIMARY KEY into which a NULL is being inserted, that NULL will be
** translated into a unique ID for the row. But on a BEFORE trigger,
** we do not know what the unique ID will be (because the insert has
** not happened yet) so we substitute a rowid of -1
*/
if( keyColumn<0 ){
sqlite3VdbeAddOp(v, OP_Integer, -1, 0);
}else if( useTempTable ){
sqlite3VdbeAddOp(v, OP_Column, srcTab, keyColumn);
}else if( pSelect ){
sqlite3VdbeAddOp(v, OP_Dup, nColumn - keyColumn - 1, 1);
}else{
sqlite3ExprCode(pParse, pList->a[keyColumn].pExpr);
sqlite3VdbeAddOp(v, OP_NotNull, -1, sqlite3VdbeCurrentAddr(v)+3);
sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
sqlite3VdbeAddOp(v, OP_Integer, -1, 0);
sqlite3VdbeAddOp(v, OP_MustBeInt, 0, 0);
}
/* Create the new column data
*/
for(i=0; i<pTab->nCol; i++){
if( pColumn==0 ){
j = i;
}else{
for(j=0; j<pColumn->nId; j++){
if( pColumn->a[j].idx==i ) break;
}
}
if( pColumn && j>=pColumn->nId ){
sqlite3VdbeOp3(v, OP_String8, 0, 0, pTab->aCol[i].zDflt, P3_STATIC);
}else if( useTempTable ){
sqlite3VdbeAddOp(v, OP_Column, srcTab, j);
}else if( pSelect ){
sqlite3VdbeAddOp(v, OP_Dup, nColumn-j-1, 1);
}else{
sqlite3ExprCode(pParse, pList->a[j].pExpr);
}
}
sqlite3VdbeAddOp(v, OP_MakeRecord, pTab->nCol, 0);
/* If this is an INSERT on a view with an INSTEAD OF INSERT trigger,
** do not attempt any conversions before assembling the record.
** If this is a real table, attempt conversions as required by the
** table column affinities.
*/
if( !isView ){
sqlite3TableAffinityStr(v, pTab);
}
sqlite3VdbeAddOp(v, OP_PutIntKey, newIdx, 0);
/* Fire BEFORE or INSTEAD OF triggers */
if( sqlite3CodeRowTrigger(pParse, TK_INSERT, 0, TK_BEFORE, pTab,
newIdx, -1, onError, endOfLoop) ){
goto insert_cleanup;
}
}
/* If any triggers exists, the opening of tables and indices is deferred
** until now.
*/
if( row_triggers_exist && !isView ){
base = pParse->nTab;
sqlite3OpenTableAndIndices(pParse, pTab, base, OP_OpenWrite);
}
/* Push the record number for the new entry onto the stack. The
** record number is a randomly generate integer created by NewRecno
** except when the table has an INTEGER PRIMARY KEY column, in which
** case the record number is the same as that column.
*/
if( !isView ){
if( keyColumn>=0 ){
if( useTempTable ){
sqlite3VdbeAddOp(v, OP_Column, srcTab, keyColumn);
}else if( pSelect ){
sqlite3VdbeAddOp(v, OP_Dup, nColumn - keyColumn - 1, 1);
}else{
sqlite3ExprCode(pParse, pList->a[keyColumn].pExpr);
}
/* If the PRIMARY KEY expression is NULL, then use OP_NewRecno
** to generate a unique primary key value.
*/
sqlite3VdbeAddOp(v, OP_NotNull, -1, sqlite3VdbeCurrentAddr(v)+3);
sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
sqlite3VdbeAddOp(v, OP_NewRecno, base, 0);
sqlite3VdbeAddOp(v, OP_MustBeInt, 0, 0);
}else{
sqlite3VdbeAddOp(v, OP_NewRecno, base, 0);
}
/* Push onto the stack, data for all columns of the new entry, beginning
** with the first column.
*/
for(i=0; i<pTab->nCol; i++){
if( i==pTab->iPKey ){
/* The value of the INTEGER PRIMARY KEY column is always a NULL.
** Whenever this column is read, the record number will be substituted
** in its place. So will fill this column with a NULL to avoid
** taking up data space with information that will never be used. */
sqlite3VdbeAddOp(v, OP_String8, 0, 0);
continue;
}
if( pColumn==0 ){
j = i;
}else{
for(j=0; j<pColumn->nId; j++){
if( pColumn->a[j].idx==i ) break;
}
}
if( pColumn && j>=pColumn->nId ){
sqlite3VdbeOp3(v, OP_String8, 0, 0, pTab->aCol[i].zDflt, P3_STATIC);
}else if( useTempTable ){
sqlite3VdbeAddOp(v, OP_Column, srcTab, j);
}else if( pSelect ){
sqlite3VdbeAddOp(v, OP_Dup, i+nColumn-j, 1);
}else{
sqlite3ExprCode(pParse, pList->a[j].pExpr);
}
}
/* Generate code to check constraints and generate index keys and
** do the insertion.
*/
sqlite3GenerateConstraintChecks(pParse, pTab, base, 0, keyColumn>=0,
0, onError, endOfLoop);
sqlite3CompleteInsertion(pParse, pTab, base, 0,0,0,
after_triggers ? newIdx : -1);
}
/* Update the count of rows that are inserted
*/
if( (db->flags & SQLITE_CountRows)!=0 ){
sqlite3VdbeAddOp(v, OP_MemIncr, iCntMem, 0);
}
if( row_triggers_exist ){
/* Close all tables opened */
if( !isView ){
sqlite3VdbeAddOp(v, OP_Close, base, 0);
for(idx=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, idx++){
sqlite3VdbeAddOp(v, OP_Close, idx+base, 0);
}
}
/* Code AFTER triggers */
if( sqlite3CodeRowTrigger(pParse, TK_INSERT, 0, TK_AFTER, pTab, newIdx, -1,
onError, endOfLoop) ){
goto insert_cleanup;
}
}
/* The bottom of the loop, if the data source is a SELECT statement
*/
sqlite3VdbeResolveLabel(v, endOfLoop);
if( useTempTable ){
sqlite3VdbeAddOp(v, OP_Next, srcTab, iCont);
sqlite3VdbeResolveLabel(v, iBreak);
sqlite3VdbeAddOp(v, OP_Close, srcTab, 0);
}else if( pSelect ){
sqlite3VdbeAddOp(v, OP_Pop, nColumn, 0);
sqlite3VdbeAddOp(v, OP_Return, 0, 0);
sqlite3VdbeResolveLabel(v, iCleanup);
}
if( !row_triggers_exist ){
/* Close all tables opened */
sqlite3VdbeAddOp(v, OP_Close, base, 0);
for(idx=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, idx++){
sqlite3VdbeAddOp(v, OP_Close, idx+base, 0);
}
}
sqlite3EndWriteOperation(pParse);
/*
** Return the number of rows inserted.
*/
if( db->flags & SQLITE_CountRows ){
sqlite3VdbeAddOp(v, OP_MemLoad, iCntMem, 0);
sqlite3VdbeAddOp(v, OP_Callback, 1, 0);
sqlite3VdbeSetNumCols(v, 1);
sqlite3VdbeSetColName(v, 0, "rows inserted", P3_STATIC);
}
insert_cleanup:
sqlite3SrcListDelete(pTabList);
if( pList ) sqlite3ExprListDelete(pList);
if( pSelect ) sqlite3SelectDelete(pSelect);
sqlite3IdListDelete(pColumn);
}
/*
** 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);
}
/*
** Process a DELETE FROM statement.
*/
void sqlite3DeleteFrom(
Parse *pParse, /* The parser context */
SrcList *pTabList, /* The table from which we should delete things */
Expr *pWhere /* The WHERE clause. May be null */
) {
Vdbe *v; /* The virtual database engine */
Table *pTab; /* The table from which records will be deleted */
const char *zDb; /* Name of database holding pTab */
int end, addr = 0; /* A couple addresses of generated code */
int i; /* Loop counter */
WhereInfo *pWInfo; /* Information about the WHERE clause */
Index *pIdx; /* For looping over indices of the table */
int iCur; /* VDBE Cursor number for pTab */
sqlite *db; /* Main database structure */
int isView; /* True if attempting to delete from a view */
AuthContext sContext; /* Authorization context */
int row_triggers_exist = 0; /* True if any triggers exist */
int before_triggers; /* True if there are BEFORE triggers */
int after_triggers; /* True if there are AFTER triggers */
int oldIdx = -1; /* Cursor for the OLD table of AFTER triggers */
sContext.pParse = 0;
if( pParse->nErr || sqlite3_malloc_failed ) {
pTabList = 0;
goto delete_from_cleanup;
}
db = pParse->db;
assert( pTabList->nSrc==1 );
/* Locate the table which we want to delete. This table has to be
** put in an SrcList structure because some of the subroutines we
** will be calling are designed to work with multiple tables and expect
** an SrcList* parameter instead of just a Table* parameter.
*/
pTab = sqlite3SrcListLookup(pParse, pTabList);
if( pTab==0 ) goto delete_from_cleanup;
before_triggers = sqlite3TriggersExist(pParse, pTab->pTrigger,
TK_DELETE, TK_BEFORE, TK_ROW, 0);
after_triggers = sqlite3TriggersExist(pParse, pTab->pTrigger,
TK_DELETE, TK_AFTER, TK_ROW, 0);
row_triggers_exist = before_triggers || after_triggers;
isView = pTab->pSelect!=0;
if( sqlite3IsReadOnly(pParse, pTab, before_triggers) ) {
goto delete_from_cleanup;
}
assert( pTab->iDb<db->nDb );
zDb = db->aDb[pTab->iDb].zName;
if( sqlite3AuthCheck(pParse, SQLITE_DELETE, pTab->zName, 0, zDb) ) {
goto delete_from_cleanup;
}
/* If pTab is really a view, make sure it has been initialized.
*/
if( isView && sqlite3ViewGetColumnNames(pParse, pTab) ) {
goto delete_from_cleanup;
}
/* Allocate a cursor used to store the old.* data for a trigger.
*/
if( row_triggers_exist ) {
oldIdx = pParse->nTab++;
}
/* Resolve the column names in all the expressions.
*/
assert( pTabList->nSrc==1 );
iCur = pTabList->a[0].iCursor = pParse->nTab++;
if( pWhere ) {
if( sqlite3ExprResolveIds(pParse, pTabList, 0, pWhere) ) {
goto delete_from_cleanup;
}
if( sqlite3ExprCheck(pParse, pWhere, 0, 0) ) {
goto delete_from_cleanup;
}
}
/* Start the view context
*/
if( isView ) {
sqlite3AuthContextPush(pParse, &sContext, pTab->zName);
}
/* Begin generating code.
*/
v = sqlite3GetVdbe(pParse);
if( v==0 ) {
goto delete_from_cleanup;
}
sqlite3VdbeCountChanges(v);
sqlite3BeginWriteOperation(pParse, row_triggers_exist, pTab->iDb);
/* If we are trying to delete from a view, construct that view into
** a temporary table.
*/
if( isView ) {
Select *pView = sqlite3SelectDup(pTab->pSelect);
sqlite3Select(pParse, pView, SRT_TempTable, iCur, 0, 0, 0, 0);
sqlite3SelectDelete(pView);
}
/* Initialize the counter of the number of rows deleted, if
** we are counting rows.
*/
if( db->flags & SQLITE_CountRows ) {
sqlite3VdbeAddOp(v, OP_Integer, 0, 0);
}
/* Special case: A DELETE without a WHERE clause deletes everything.
** It is easier just to erase the whole table. Note, however, that
** this means that the row change count will be incorrect.
*/
if( pWhere==0 && !row_triggers_exist ) {
if( db->flags & SQLITE_CountRows ) {
/* If counting rows deleted, just count the total number of
** entries in the table. */
int endOfLoop = sqlite3VdbeMakeLabel(v);
int addr;
if( !isView ) {
sqlite3VdbeAddOp(v, OP_Integer, pTab->iDb, 0);
sqlite3VdbeAddOp(v, OP_OpenRead, iCur, pTab->tnum);
sqlite3VdbeAddOp(v, OP_SetNumColumns, iCur, pTab->nCol);
}
sqlite3VdbeAddOp(v, OP_Rewind, iCur, sqlite3VdbeCurrentAddr(v)+2);
addr = sqlite3VdbeAddOp(v, OP_AddImm, 1, 0);
sqlite3VdbeAddOp(v, OP_Next, iCur, addr);
sqlite3VdbeResolveLabel(v, endOfLoop);
sqlite3VdbeAddOp(v, OP_Close, iCur, 0);
}
if( !isView ) {
sqlite3VdbeAddOp(v, OP_Clear, pTab->tnum, pTab->iDb);
for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext) {
sqlite3VdbeAddOp(v, OP_Clear, pIdx->tnum, pIdx->iDb);
}
}
}
/* The usual case: There is a WHERE clause so we have to scan through
** the table and pick which records to delete.
*/
else {
/* Ensure all required collation sequences are available. */
for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext) {
if( sqlite3CheckIndexCollSeq(pParse, pIdx) ) {
goto delete_from_cleanup;
}
}
/* Begin the database scan
*/
pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 1, 0);
if( pWInfo==0 ) goto delete_from_cleanup;
/* Remember the key of every item to be deleted.
*/
sqlite3VdbeAddOp(v, OP_ListWrite, 0, 0);
if( db->flags & SQLITE_CountRows ) {
sqlite3VdbeAddOp(v, OP_AddImm, 1, 0);
}
/* End the database scan loop.
*/
sqlite3WhereEnd(pWInfo);
/* Open the pseudo-table used to store OLD if there are triggers.
*/
if( row_triggers_exist ) {
sqlite3VdbeAddOp(v, OP_OpenPseudo, oldIdx, 0);
sqlite3VdbeAddOp(v, OP_SetNumColumns, oldIdx, pTab->nCol);
}
/* Delete every item whose key was written to the list during the
** database scan. We have to delete items after the scan is complete
** because deleting an item can change the scan order.
*/
sqlite3VdbeAddOp(v, OP_ListRewind, 0, 0);
end = sqlite3VdbeMakeLabel(v);
/* This is the beginning of the delete loop when there are
** row triggers.
*/
if( row_triggers_exist ) {
addr = sqlite3VdbeAddOp(v, OP_ListRead, 0, end);
sqlite3VdbeAddOp(v, OP_Dup, 0, 0);
if( !isView ) {
sqlite3VdbeAddOp(v, OP_Integer, pTab->iDb, 0);
sqlite3VdbeAddOp(v, OP_OpenRead, iCur, pTab->tnum);
sqlite3VdbeAddOp(v, OP_SetNumColumns, iCur, pTab->nCol);
}
sqlite3VdbeAddOp(v, OP_MoveGe, iCur, 0);
sqlite3VdbeAddOp(v, OP_Recno, iCur, 0);
sqlite3VdbeAddOp(v, OP_RowData, iCur, 0);
sqlite3VdbeAddOp(v, OP_PutIntKey, oldIdx, 0);
if( !isView ) {
sqlite3VdbeAddOp(v, OP_Close, iCur, 0);
}
sqlite3CodeRowTrigger(pParse, TK_DELETE, 0, TK_BEFORE, pTab, -1,
oldIdx, (pParse->trigStack)?pParse->trigStack->orconf:OE_Default,
addr);
}
if( !isView ) {
/* Open cursors for the table we are deleting from and all its
** indices. If there are row triggers, this happens inside the
** OP_ListRead loop because the cursor have to all be closed
** before the trigger fires. If there are no row triggers, the
** cursors are opened only once on the outside the loop.
*/
pParse->nTab = iCur + 1;
sqlite3OpenTableAndIndices(pParse, pTab, iCur);
/* This is the beginning of the delete loop when there are no
** row triggers */
if( !row_triggers_exist ) {
addr = sqlite3VdbeAddOp(v, OP_ListRead, 0, end);
}
/* Delete the row */
sqlite3GenerateRowDelete(db, v, pTab, iCur, 1);
}
/* If there are row triggers, close all cursors then invoke
** the AFTER triggers
*/
if( row_triggers_exist ) {
if( !isView ) {
for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext) {
sqlite3VdbeAddOp(v, OP_Close, iCur + i, pIdx->tnum);
}
sqlite3VdbeAddOp(v, OP_Close, iCur, 0);
}
sqlite3CodeRowTrigger(pParse, TK_DELETE, 0, TK_AFTER, pTab, -1,
oldIdx, (pParse->trigStack)?pParse->trigStack->orconf:OE_Default,
addr);
}
/* End of the delete loop */
sqlite3VdbeAddOp(v, OP_Goto, 0, addr);
sqlite3VdbeResolveLabel(v, end);
sqlite3VdbeAddOp(v, OP_ListReset, 0, 0);
/* Close the cursors after the loop if there are no row triggers */
if( !row_triggers_exist ) {
for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext) {
sqlite3VdbeAddOp(v, OP_Close, iCur + i, pIdx->tnum);
}
sqlite3VdbeAddOp(v, OP_Close, iCur, 0);
pParse->nTab = iCur;
}
}
sqlite3EndWriteOperation(pParse);
/*
** Return the number of rows that were deleted.
*/
if( db->flags & SQLITE_CountRows ) {
sqlite3VdbeAddOp(v, OP_Callback, 1, 0);
sqlite3VdbeSetNumCols(v, 1);
sqlite3VdbeSetColName(v, 0, "rows deleted", P3_STATIC);
}
delete_from_cleanup:
sqlite3AuthContextPop(&sContext);
sqlite3SrcListDelete(pTabList);
sqlite3ExprDelete(pWhere);
return;
}