/*
** Create a new sqlite3_value object, containing the value of pExpr.
**
** This only works for very simple expressions that consist of one constant
** token (i.e. "5", "5.1", "'a string'"). If the expression can
** be converted directly into a value, then the value is allocated and
** a pointer written to *ppVal. The caller is responsible for deallocating
** the value by passing it to sqlite3ValueFree() later on. If the expression
** cannot be converted to a value, then *ppVal is set to NULL.
*/
int sqlite3ValueFromExpr(
sqlite3 *db, /* The database connection */
Expr *pExpr, /* The expression to evaluate */
u8 enc, /* Encoding to use */
u8 affinity, /* Affinity to use */
sqlite3_value **ppVal /* Write the new value here */
){
int op;
char *zVal = 0;
sqlite3_value *pVal = 0;
if( !pExpr ){
*ppVal = 0;
return SQLITE_OK;
}
op = pExpr->op;
if( op==TK_STRING || op==TK_FLOAT || op==TK_INTEGER ){
zVal = sqlite3DbStrNDup(db, (char*)pExpr->token.z, pExpr->token.n);
pVal = sqlite3ValueNew(db);
if( !zVal || !pVal ) goto no_mem;
sqlite3Dequote(zVal);
sqlite3ValueSetStr(pVal, -1, zVal, SQLITE_UTF8, SQLITE_DYNAMIC);
if( (op==TK_INTEGER || op==TK_FLOAT ) && affinity==SQLITE_AFF_NONE ){
sqlite3ValueApplyAffinity(pVal, SQLITE_AFF_NUMERIC, enc);
}else{
sqlite3ValueApplyAffinity(pVal, affinity, enc);
}
}else if( op==TK_UMINUS ) {
if( SQLITE_OK==sqlite3ValueFromExpr(db,pExpr->pLeft,enc,affinity,&pVal) ){
pVal->u.i = -1 * pVal->u.i;
pVal->r = -1.0 * pVal->r;
}
}
#ifndef SQLITE_OMIT_BLOB_LITERAL
else if( op==TK_BLOB ){
int nVal;
assert( pExpr->token.n>=3 );
assert( pExpr->token.z[0]=='x' || pExpr->token.z[0]=='X' );
assert( pExpr->token.z[1]=='\'' );
assert( pExpr->token.z[pExpr->token.n-1]=='\'' );
pVal = sqlite3ValueNew(db);
if( !pVal ) goto no_mem;
nVal = pExpr->token.n - 3;
zVal = (char*)pExpr->token.z + 2;
sqlite3VdbeMemSetStr(pVal, sqlite3HexToBlob(db, zVal, nVal), nVal/2,
0, SQLITE_DYNAMIC);
}
#endif
*ppVal = pVal;
return SQLITE_OK;
no_mem:
db->mallocFailed = 1;
sqlite3DbFree(db, zVal);
sqlite3ValueFree(pVal);
*ppVal = 0;
return SQLITE_NOMEM;
}
/*
** The most recently coded instruction was an OP_Column to retrieve column
** 'i' of table pTab. This routine sets the P3 parameter of the
** OP_Column to the default value, if any.
**
** The default value of a column is specified by a DEFAULT clause in the
** column definition. This was either supplied by the user when the table
** was created, or added later to the table definition by an ALTER TABLE
** command. If the latter, then the row-records in the table btree on disk
** may not contain a value for the column and the default value, taken
** from the P3 parameter of the OP_Column instruction, is returned instead.
** If the former, then all row-records are guaranteed to include a value
** for the column and the P3 value is not required.
**
** Column definitions created by an ALTER TABLE command may only have
** literal default values specified: a number, null or a string. (If a more
** complicated default expression value was provided, it is evaluated
** when the ALTER TABLE is executed and one of the literal values written
** into the sqlite_master table.)
**
** Therefore, the P3 parameter is only required if the default value for
** the column is a literal number, string or null. The sqlite3ValueFromExpr()
** function is capable of transforming these types of expressions into
** sqlite3_value objects.
*/
void sqlite3ColumnDefault(Vdbe *v, Table *pTab, int i){
if( pTab && !pTab->pSelect ){
sqlite3_value *pValue;
u8 enc = sqlite3VdbeDb(v)->enc;
Column *pCol = &pTab->aCol[i];
sqlite3ValueFromExpr(pCol->pDflt, enc, pCol->affinity, &pValue);
sqlite3VdbeChangeP3(v, -1, (const char *)pValue, P3_MEM);
}
}
/*
** Create a new sqlite3_value object, containing the value of pExpr.
**
** This only works for very simple expressions that consist of one constant
** token (i.e. "5", "5.1", "NULL", "'a string'"). If the expression can
** be converted directly into a value, then the value is allocated and
** a pointer written to *ppVal. The caller is responsible for deallocating
** the value by passing it to sqlite3ValueFree() later on. If the expression
** cannot be converted to a value, then *ppVal is set to NULL.
*/
int sqlite3ValueFromExpr(
Expr *pExpr,
u8 enc,
u8 affinity,
sqlite3_value **ppVal
){
int op;
char *zVal = 0;
sqlite3_value *pVal = 0;
if( !pExpr ){
*ppVal = 0;
return SQLITE_OK;
}
op = pExpr->op;
if( op==TK_STRING || op==TK_FLOAT || op==TK_INTEGER ){
zVal = sqliteStrNDup(pExpr->token.z, pExpr->token.n);
pVal = sqlite3ValueNew();
if( !zVal || !pVal ) goto no_mem;
sqlite3Dequote(zVal);
sqlite3ValueSetStr(pVal, -1, zVal, SQLITE_UTF8, sqlite3FreeX);
if( (op==TK_INTEGER || op==TK_FLOAT ) && affinity==SQLITE_AFF_NONE ){
sqlite3ValueApplyAffinity(pVal, SQLITE_AFF_NUMERIC, enc);
}else{
sqlite3ValueApplyAffinity(pVal, affinity, enc);
}
}else if( op==TK_UMINUS ) {
if( SQLITE_OK==sqlite3ValueFromExpr(pExpr->pLeft, enc, affinity, &pVal) ){
pVal->i = -1 * pVal->i;
pVal->r = -1.0 * pVal->r;
}
}
#ifndef SQLITE_OMIT_BLOB_LITERAL
else if( op==TK_BLOB ){
int nVal;
pVal = sqlite3ValueNew();
zVal = sqliteStrNDup(pExpr->token.z+1, pExpr->token.n-1);
if( !zVal || !pVal ) goto no_mem;
sqlite3Dequote(zVal);
nVal = strlen(zVal)/2;
sqlite3VdbeMemSetStr(pVal, sqlite3HexToBlob(zVal), nVal, 0, sqlite3FreeX);
sqliteFree(zVal);
}
#endif
*ppVal = pVal;
return SQLITE_OK;
no_mem:
sqliteFree(zVal);
sqlite3ValueFree(pVal);
*ppVal = 0;
return SQLITE_NOMEM;
}
/*
** The most recently coded instruction was an OP_Column to retrieve the
** i-th column of table pTab. This routine sets the P3 parameter of the
** OP_Column to the default value, if any.
**
** The default value of a column is specified by a DEFAULT clause in the
** column definition. This was either supplied by the user when the table
** was created, or added later to the table definition by an ALTER TABLE
** command. If the latter, then the row-records in the table btree on disk
** may not contain a value for the column and the default value, taken
** from the P3 parameter of the OP_Column instruction, is returned instead.
** If the former, then all row-records are guaranteed to include a value
** for the column and the P3 value is not required.
**
** Column definitions created by an ALTER TABLE command may only have
** literal default values specified: a number, null or a string. (If a more
** complicated default expression value was provided, it is evaluated
** when the ALTER TABLE is executed and one of the literal values written
** into the sqlite_master table.)
**
** Therefore, the P3 parameter is only required if the default value for
** the column is a literal number, string or null. The sqlite3ValueFromExpr()
** function is capable of transforming these types of expressions into
** sqlite3_value objects.
*/
void sqlite3ColumnDefault(Vdbe *v, Table *pTab, int i){
if( pTab && !pTab->pSelect ){
sqlite3_value *pValue;
u8 enc = ENC(sqlite3VdbeDb(v));
Column *pCol = &pTab->aCol[i];
sqlite3ValueFromExpr(pCol->pDflt, enc, pCol->affinity, &pValue);
if( pValue ){
sqlite3VdbeChangeP3(v, -1, (const char *)pValue, P3_MEM);
}else{
VdbeComment((v, "# %s.%s", pTab->zName, pCol->zName));
}
}
}
/*
** The most recently coded instruction was an OP_Column to retrieve the
** i-th column of table pTab. This routine sets the P4 parameter of the
** OP_Column to the default value, if any.
**
** The default value of a column is specified by a DEFAULT clause in the
** column definition. This was either supplied by the user when the table
** was created, or added later to the table definition by an ALTER TABLE
** command. If the latter, then the row-records in the table btree on disk
** may not contain a value for the column and the default value, taken
** from the P4 parameter of the OP_Column instruction, is returned instead.
** If the former, then all row-records are guaranteed to include a value
** for the column and the P4 value is not required.
**
** Column definitions created by an ALTER TABLE command may only have
** literal default values specified: a number, null or a string. (If a more
** complicated default expression value was provided, it is evaluated
** when the ALTER TABLE is executed and one of the literal values written
** into the sqlite_master table.)
**
** Therefore, the P4 parameter is only required if the default value for
** the column is a literal number, string or null. The sqlite3ValueFromExpr()
** function is capable of transforming these types of expressions into
** sqlite3_value objects.
**
** If parameter iReg is not negative, code an OP_RealAffinity instruction
** on register iReg. This is used when an equivalent integer value is
** stored in place of an 8-byte floating point value in order to save
** space.
*/
void sqlite3ColumnDefault(Vdbe *v, Table *pTab, int i, int iReg){
assert( pTab!=0 );
if( !pTab->pSelect ){
sqlite3_value *pValue = 0;
u8 enc = ENC(sqlite3VdbeDb(v));
Column *pCol = &pTab->aCol[i];
VdbeComment((v, "%s.%s", pTab->zName, pCol->zName));
assert( i<pTab->nCol );
sqlite3ValueFromExpr(sqlite3VdbeDb(v), pCol->pDflt, enc,
pCol->affinity, &pValue);
if( pValue ){
sqlite3VdbeChangeP4(v, -1, (const char *)pValue, P4_MEM);
}
#ifndef SQLITE_OMIT_FLOATING_POINT
if( pTab->aCol[i].affinity==SQLITE_AFF_REAL ){
sqlite3VdbeAddOp1(v, OP_RealAffinity, iReg);
}
#endif
}
}
/*
** This function is called after an "ALTER TABLE ... ADD" statement
** has been parsed. Argument pColDef contains the text of the new
** column definition.
**
** The Table structure pParse->pNewTable was extended to include
** the new column during parsing.
*/
void sqlite3AlterFinishAddColumn(Parse *pParse, Token *pColDef){
Table *pNew; /* Copy of pParse->pNewTable */
Table *pTab; /* Table being altered */
int iDb; /* Database number */
const char *zDb; /* Database name */
const char *zTab; /* Table name */
char *zCol; /* Null-terminated column definition */
Column *pCol; /* The new column */
Expr *pDflt; /* Default value for the new column */
if( pParse->nErr ) return;
pNew = pParse->pNewTable;
assert( pNew );
iDb = sqlite3SchemaToIndex(pParse->db, pNew->pSchema);
zDb = pParse->db->aDb[iDb].zName;
zTab = pNew->zName;
pCol = &pNew->aCol[pNew->nCol-1];
pDflt = pCol->pDflt;
pTab = sqlite3FindTable(pParse->db, zTab, zDb);
assert( pTab );
#ifndef SQLITE_OMIT_AUTHORIZATION
/* Invoke the authorization callback. */
if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab->zName, 0) ){
return;
}
#endif
/* If the default value for the new column was specified with a
** literal NULL, then set pDflt to 0. This simplifies checking
** for an SQL NULL default below.
*/
if( pDflt && pDflt->op==TK_NULL ){
pDflt = 0;
}
/* Check that the new column is not specified as PRIMARY KEY or UNIQUE.
** If there is a NOT NULL constraint, then the default value for the
** column must not be NULL.
*/
if( pCol->isPrimKey ){
sqlite3ErrorMsg(pParse, "Cannot add a PRIMARY KEY column");
return;
}
if( pNew->pIndex ){
sqlite3ErrorMsg(pParse, "Cannot add a UNIQUE column");
return;
}
if( pCol->notNull && !pDflt ){
sqlite3ErrorMsg(pParse,
"Cannot add a NOT NULL column with default value NULL");
return;
}
/* Ensure the default expression is something that sqlite3ValueFromExpr()
** can handle (i.e. not CURRENT_TIME etc.)
*/
if( pDflt ){
sqlite3_value *pVal;
if( sqlite3ValueFromExpr(pDflt, SQLITE_UTF8, SQLITE_AFF_NONE, &pVal) ){
/* malloc() has failed */
return;
}
if( !pVal ){
sqlite3ErrorMsg(pParse, "Cannot add a column with non-constant default");
return;
}
sqlite3ValueFree(pVal);
}
/* Modify the CREATE TABLE statement. */
zCol = sqliteStrNDup((char*)pColDef->z, pColDef->n);
if( zCol ){
char *zEnd = &zCol[pColDef->n-1];
while( (zEnd>zCol && *zEnd==';') || isspace(*(unsigned char *)zEnd) ){
*zEnd-- = '\0';
}
sqlite3NestedParse(pParse,
"UPDATE %Q.%s SET "
"sql = substr(sql,1,%d) || ', ' || %Q || substr(sql,%d,length(sql)) "
"WHERE type = 'table' AND name = %Q",
zDb, SCHEMA_TABLE(iDb), pNew->addColOffset, zCol, pNew->addColOffset+1,
zTab
);
sqliteFree(zCol);
}
/* If the default value of the new column is NULL, then set the file
** format to 2. If the default value of the new column is not NULL,
** the file format becomes 3.
*/
sqlite3MinimumFileFormat(pParse, iDb, pDflt ? 3 : 2);
/* Reload the schema of the modified table. */
reloadTableSchema(pParse, pTab, pTab->zName);
}
/*
** This function is called after an "ALTER TABLE ... ADD" statement
** has been parsed. Argument pColDef contains the text of the new
** column definition.
**
** The Table structure pParse->pNewTable was extended to include
** the new column during parsing.
*/
void sqlite3AlterFinishAddColumn(Parse *pParse, Token *pColDef){
Table *pNew; /* Copy of pParse->pNewTable */
Table *pTab; /* Table being altered */
int iDb; /* Database number */
const char *zDb; /* Database name */
const char *zTab; /* Table name */
char *zCol; /* Null-terminated column definition */
Column *pCol; /* The new column */
Expr *pDflt; /* Default value for the new column */
sqlite3 *db; /* The database connection; */
Vdbe *v = pParse->pVdbe; /* The prepared statement under construction */
db = pParse->db;
if( pParse->nErr || db->mallocFailed ) return;
assert( v!=0 );
pNew = pParse->pNewTable;
assert( pNew );
assert( sqlite3BtreeHoldsAllMutexes(db) );
iDb = sqlite3SchemaToIndex(db, pNew->pSchema);
zDb = db->aDb[iDb].zName;
zTab = &pNew->zName[16]; /* Skip the "sqlite_altertab_" prefix on the name */
pCol = &pNew->aCol[pNew->nCol-1];
pDflt = pCol->pDflt;
pTab = sqlite3FindTable(db, zTab, zDb);
assert( pTab );
#ifndef SQLITE_OMIT_AUTHORIZATION
/* Invoke the authorization callback. */
if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab->zName, 0) ){
return;
}
#endif
/* If the default value for the new column was specified with a
** literal NULL, then set pDflt to 0. This simplifies checking
** for an SQL NULL default below.
*/
if( pDflt && pDflt->op==TK_NULL ){
pDflt = 0;
}
/* Check that the new column is not specified as PRIMARY KEY or UNIQUE.
** If there is a NOT NULL constraint, then the default value for the
** column must not be NULL.
*/
if( pCol->colFlags & COLFLAG_PRIMKEY ){
sqlite3ErrorMsg(pParse, "Cannot add a PRIMARY KEY column");
return;
}
if( pNew->pIndex ){
sqlite3ErrorMsg(pParse, "Cannot add a UNIQUE column");
return;
}
if( (db->flags&SQLITE_ForeignKeys) && pNew->pFKey && pDflt ){
sqlite3ErrorMsg(pParse,
"Cannot add a REFERENCES column with non-NULL default value");
return;
}
if( pCol->notNull && !pDflt ){
sqlite3ErrorMsg(pParse,
"Cannot add a NOT NULL column with default value NULL");
return;
}
/* Ensure the default expression is something that sqlite3ValueFromExpr()
** can handle (i.e. not CURRENT_TIME etc.)
*/
if( pDflt ){
sqlite3_value *pVal = 0;
int rc;
rc = sqlite3ValueFromExpr(db, pDflt, SQLITE_UTF8, SQLITE_AFF_BLOB, &pVal);
assert( rc==SQLITE_OK || rc==SQLITE_NOMEM );
if( rc!=SQLITE_OK ){
assert( db->mallocFailed == 1 );
return;
}
if( !pVal ){
sqlite3ErrorMsg(pParse, "Cannot add a column with non-constant default");
return;
}
sqlite3ValueFree(pVal);
}
/* Modify the CREATE TABLE statement. */
zCol = sqlite3DbStrNDup(db, (char*)pColDef->z, pColDef->n);
if( zCol ){
char *zEnd = &zCol[pColDef->n-1];
int savedDbFlags = db->flags;
while( zEnd>zCol && (*zEnd==';' || sqlite3Isspace(*zEnd)) ){
*zEnd-- = '\0';
}
db->flags |= SQLITE_PreferBuiltin;
sqlite3NestedParse(pParse,
"UPDATE \"%w\".%s SET "
"sql = substr(sql,1,%d) || ', ' || %Q || substr(sql,%d) "
"WHERE type = 'table' AND name = %Q",
zDb, SCHEMA_TABLE(iDb), pNew->addColOffset, zCol, pNew->addColOffset+1,
zTab
);
sqlite3DbFree(db, zCol);
db->flags = savedDbFlags;
}
/* If the default value of the new column is NULL, then the file
** format to 2. If the default value of the new column is not NULL,
** the file format be 3. Back when this feature was first added
** in 2006, we went to the trouble to upgrade the file format to the
** minimum support values. But 10-years on, we can assume that all
** extent versions of SQLite support file-format 4, so we always and
** unconditionally upgrade to 4.
*/
sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, BTREE_FILE_FORMAT,
SQLITE_MAX_FILE_FORMAT);
/* Reload the schema of the modified table. */
reloadTableSchema(pParse, pTab, pTab->zName);
}
/*
** Create a new sqlite3_value object, containing the value of pExpr.
**
** This only works for very simple expressions that consist of one constant
** token (i.e. "5", "5.1", "'a string'"). If the expression can
** be converted directly into a value, then the value is allocated and
** a pointer written to *ppVal. The caller is responsible for deallocating
** the value by passing it to sqlite3ValueFree() later on. If the expression
** cannot be converted to a value, then *ppVal is set to NULL.
*/
int sqlite3ValueFromExpr(
sqlite3 *db, /* The database connection */
Expr *pExpr, /* The expression to evaluate */
u8 enc, /* Encoding to use */
u8 affinity, /* Affinity to use */
sqlite3_value **ppVal /* Write the new value here */
){
int op;
char *zVal = 0;
sqlite3_value *pVal = 0;
int negInt = 1;
const char *zNeg = "";
if( !pExpr ){
*ppVal = 0;
return SQLITE_OK;
}
op = pExpr->op;
/* op can only be TK_REGISTER if we have compiled with SQLITE_ENABLE_STAT3.
** The ifdef here is to enable us to achieve 100% branch test coverage even
** when SQLITE_ENABLE_STAT3 is omitted.
*/
#ifdef SQLITE_ENABLE_STAT3
if( op==TK_REGISTER ) op = pExpr->op2;
#else
if( NEVER(op==TK_REGISTER) ) op = pExpr->op2;
#endif
/* Handle negative integers in a single step. This is needed in the
** case when the value is -9223372036854775808.
*/
if( op==TK_UMINUS
&& (pExpr->pLeft->op==TK_INTEGER || pExpr->pLeft->op==TK_FLOAT) ){
pExpr = pExpr->pLeft;
op = pExpr->op;
negInt = -1;
zNeg = "-";
}
if( op==TK_STRING || op==TK_FLOAT || op==TK_INTEGER ){
pVal = sqlite3ValueNew(db);
if( pVal==0 ) goto no_mem;
if( ExprHasProperty(pExpr, EP_IntValue) ){
sqlite3VdbeMemSetInt64(pVal, (i64)pExpr->u.iValue*negInt);
}else{
zVal = sqlite3MPrintf(db, "%s%s", zNeg, pExpr->u.zToken);
if( zVal==0 ) goto no_mem;
sqlite3ValueSetStr(pVal, -1, zVal, SQLITE_UTF8, SQLITE_DYNAMIC);
if( op==TK_FLOAT ) pVal->type = SQLITE_FLOAT;
}
if( (op==TK_INTEGER || op==TK_FLOAT ) && affinity==SQLITE_AFF_NONE ){
sqlite3ValueApplyAffinity(pVal, SQLITE_AFF_NUMERIC, SQLITE_UTF8);
}else{
sqlite3ValueApplyAffinity(pVal, affinity, SQLITE_UTF8);
}
if( pVal->flags & (MEM_Int|MEM_Real) ) pVal->flags &= ~MEM_Str;
if( enc!=SQLITE_UTF8 ){
sqlite3VdbeChangeEncoding(pVal, enc);
}
}else if( op==TK_UMINUS ) {
/* This branch happens for multiple negative signs. Ex: -(-5) */
if( SQLITE_OK==sqlite3ValueFromExpr(db,pExpr->pLeft,enc,affinity,&pVal) ){
sqlite3VdbeMemNumerify(pVal);
if( pVal->u.i==SMALLEST_INT64 ){
pVal->flags &= MEM_Int;
pVal->flags |= MEM_Real;
pVal->r = (double)LARGEST_INT64;
}else{
pVal->u.i = -pVal->u.i;
}
pVal->r = -pVal->r;
sqlite3ValueApplyAffinity(pVal, affinity, enc);
}
}else if( op==TK_NULL ){
pVal = sqlite3ValueNew(db);
if( pVal==0 ) goto no_mem;
}
#ifndef SQLITE_OMIT_BLOB_LITERAL
else if( op==TK_BLOB ){
int nVal;
assert( pExpr->u.zToken[0]=='x' || pExpr->u.zToken[0]=='X' );
assert( pExpr->u.zToken[1]=='\'' );
pVal = sqlite3ValueNew(db);
if( !pVal ) goto no_mem;
zVal = &pExpr->u.zToken[2];
nVal = sqlite3Strlen30(zVal)-1;
assert( zVal[nVal]=='\'' );
sqlite3VdbeMemSetStr(pVal, sqlite3HexToBlob(db, zVal, nVal), nVal/2,
0, SQLITE_DYNAMIC);
}
#endif
if( pVal ){
sqlite3VdbeMemStoreType(pVal);
}
*ppVal = pVal;
return SQLITE_OK;
no_mem:
db->mallocFailed = 1;
sqlite3DbFree(db, zVal);
sqlite3ValueFree(pVal);
*ppVal = 0;
return SQLITE_NOMEM;
}
/*
** Create a new sqlite3_value object, containing the value of pExpr.
**
** This only works for very simple expressions that consist of one constant
** token (i.e. "5", "5.1", "'a string'"). If the expression can
** be converted directly into a value, then the value is allocated and
** a pointer written to *ppVal. The caller is responsible for deallocating
** the value by passing it to sqlite3ValueFree() later on. If the expression
** cannot be converted to a value, then *ppVal is set to NULL.
*/
int sqlite3ValueFromExpr(
sqlite3 *db, /* The database connection */
Expr *pExpr, /* The expression to evaluate */
u8 enc, /* Encoding to use */
u8 affinity, /* Affinity to use */
sqlite3_value **ppVal /* Write the new value here */
){
int op;
char *zVal = 0;
sqlite3_value *pVal = 0;
if( !pExpr ){
*ppVal = 0;
return SQLITE_OK;
}
op = pExpr->op;
if( op==TK_REGISTER ){
op = pExpr->op2;
}
if( op==TK_STRING || op==TK_FLOAT || op==TK_INTEGER ){
pVal = sqlite3ValueNew(db);
if( pVal==0 ) goto no_mem;
if( ExprHasProperty(pExpr, EP_IntValue) ){
sqlite3VdbeMemSetInt64(pVal, (i64)pExpr->u.iValue);
}else{
zVal = sqlite3DbStrDup(db, pExpr->u.zToken);
if( zVal==0 ) goto no_mem;
sqlite3ValueSetStr(pVal, -1, zVal, SQLITE_UTF8, SQLITE_DYNAMIC);
if( op==TK_FLOAT ) pVal->type = SQLITE_FLOAT;
}
if( (op==TK_INTEGER || op==TK_FLOAT ) && affinity==SQLITE_AFF_NONE ){
sqlite3ValueApplyAffinity(pVal, SQLITE_AFF_NUMERIC, SQLITE_UTF8);
}else{
sqlite3ValueApplyAffinity(pVal, affinity, SQLITE_UTF8);
}
if( enc!=SQLITE_UTF8 ){
sqlite3VdbeChangeEncoding(pVal, enc);
}
}else if( op==TK_UMINUS ) {
if( SQLITE_OK==sqlite3ValueFromExpr(db,pExpr->pLeft,enc,affinity,&pVal) ){
pVal->u.i = -1 * pVal->u.i;
/* (double)-1 In case of SQLITE_OMIT_FLOATING_POINT... */
pVal->r = (double)-1 * pVal->r;
}
}
#ifndef SQLITE_OMIT_BLOB_LITERAL
else if( op==TK_BLOB ){
int nVal;
assert( pExpr->u.zToken[0]=='x' || pExpr->u.zToken[0]=='X' );
assert( pExpr->u.zToken[1]=='\'' );
pVal = sqlite3ValueNew(db);
if( !pVal ) goto no_mem;
zVal = &pExpr->u.zToken[2];
nVal = sqlite3Strlen30(zVal)-1;
assert( zVal[nVal]=='\'' );
sqlite3VdbeMemSetStr(pVal, sqlite3HexToBlob(db, zVal, nVal), nVal/2,
0, SQLITE_DYNAMIC);
}
#endif
*ppVal = pVal;
return SQLITE_OK;
no_mem:
db->mallocFailed = 1;
sqlite3DbFree(db, zVal);
sqlite3ValueFree(pVal);
*ppVal = 0;
return SQLITE_NOMEM;
}
/*
** This function is called after an "ALTER TABLE ... ADD" statement
** has been parsed. Argument pColDef contains the text of the new
** column definition.
**
** The Table structure pParse->pNewTable was extended to include
** the new column during parsing.
在“ALTER TABLE…添加“声明解析后这个函数被调用。
参数pColDef包含新列定义的文本。
表结构pParse - > pNewTable扩大到包括在解析新列。
*/
void sqlite3AlterFinishAddColumn(Parse *pParse, Token *pColDef){
Table *pNew; /* Copy of pParse->pNewTable pParse->pNew表的副本*/
Table *pTab; /* Table being altered 被修改的表*/
int iDb; /* Database number 数据库数*/
const char *zDb; /* Database name 数据库名*/
const char *zTab; /* Table name 表名*/
char *zCol; /* Null-terminated column definition 空值终止列定义*/
Column *pCol; /* The new column 新列*/
Expr *pDflt; /* Default value for the new column 为新列默认数值*/
sqlite3 *db; /* The database connection; 数据库的连接*/
db = pParse->db;
if( pParse->nErr || db->mallocFailed ) return;
pNew = pParse->pNewTable;
assert( pNew );
assert( sqlite3BtreeHoldsAllMutexes(db) );
iDb = sqlite3SchemaToIndex(db, pNew->pSchema);
zDb = db->aDb[iDb].zName;
zTab = &pNew->zName[16]; /* Skip the "sqlite_altertab_" prefix on the name 跳过“sqlite_altertab_”前缀的名称*/
pCol = &pNew->aCol[pNew->nCol-1];
pDflt = pCol->pDflt;
pTab = sqlite3FindTable(db, zTab, zDb);
assert( pTab );
#ifndef SQLITE_OMIT_AUTHORIZATION
/* Invoke the authorization callback. 调用授权回调*/
if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab->zName, 0) ){
return;
}
#endif
/* If the default value for the new column was specified with a
** literal NULL, then set pDflt to 0. This simplifies checking
** for an SQL NULL default below.
如果新列的默认值是用文字指定NULL,那么pDflt设置为0。
这简化了检查SQL空下面的默认。
*/
if( pDflt && pDflt->op==TK_NULL ){
pDflt = 0;
}
/* Check that the new column is not specified as PRIMARY KEY or UNIQUE.
** If there is a NOT NULL constraint, then the default value for the
** column must not be NULL.
检查新列没有指定主键或唯一的。
如果有一个非空约束,然后列的默认值不能为空。
*/
if( pCol->isPrimKey ){
sqlite3ErrorMsg(pParse, "Cannot add a PRIMARY KEY column");
return;
}
if( pNew->pIndex ){
sqlite3ErrorMsg(pParse, "Cannot add a UNIQUE column");
return;
}
if( (db->flags&SQLITE_ForeignKeys) && pNew->pFKey && pDflt ){
sqlite3ErrorMsg(pParse,
"Cannot add a REFERENCES column with non-NULL default value");
return;
}
if( pCol->notNull && !pDflt ){
sqlite3ErrorMsg(pParse,
"Cannot add a NOT NULL column with default value NULL");
return;
}
/* Ensure the default expression is something that sqlite3ValueFromExpr()
** can handle (i.e. not CURRENT_TIME etc.)
确保默认表达式是sqlite3ValueFromExpr()可以处理的事(即不是当前时间等。)
*/
if( pDflt ){
sqlite3_value *pVal;
if( sqlite3ValueFromExpr(db, pDflt, SQLITE_UTF8, SQLITE_AFF_NONE, &pVal) ){
db->mallocFailed = 1;
return;
}
if( !pVal ){
sqlite3ErrorMsg(pParse, "Cannot add a column with non-constant default");
return;
}
sqlite3ValueFree(pVal);
}
/* Modify the CREATE TABLE statement. 修改CREATE TABLE语句。*/
zCol = sqlite3DbStrNDup(db, (char*)pColDef->z, pColDef->n);
if( zCol ){
char *zEnd = &zCol[pColDef->n-1];
int savedDbFlags = db->flags;
while( zEnd>zCol && (*zEnd==';' || sqlite3Isspace(*zEnd)) ){
*zEnd-- = '\0';
}
db->flags |= SQLITE_PreferBuiltin;
sqlite3NestedParse(pParse,
"UPDATE \"%w\".%s SET "
"sql = substr(sql,1,%d) || ', ' || %Q || substr(sql,%d) "
"WHERE type = 'table' AND name = %Q",
zDb, SCHEMA_TABLE(iDb), pNew->addColOffset, zCol, pNew->addColOffset+1,
zTab
);
sqlite3DbFree(db, zCol);
db->flags = savedDbFlags;
}
/* If the default value of the new column is NULL, then set the file
** format to 2. If the default value of the new column is not NULL,
** the file format becomes 3.
如果新列的默认值为空,那么将文件格式设置为2。如果新列的默认值不为空,文件格式变成3。
*/
sqlite3MinimumFileFormat(pParse, iDb, pDflt ? 3 : 2);
/* Reload the schema of the modified table. 重新加载修改后的表的模式。*/
reloadTableSchema(pParse, pTab, pTab->zName);
}
