/*
** 2005 February 15
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that used to generate VDBE code
** that implements the ALTER TABLE command.
*/
#include "sqliteInt.h"
/*
** The code in this file only exists if we are not omitting the
** ALTER TABLE logic from the build.
*/
#ifndef SQLITE_OMIT_ALTERTABLE
/*
** This function is used by SQL generated to implement the
** ALTER TABLE command. The first argument is the text of a CREATE TABLE or
** CREATE INDEX command. The second is a table name. The table name in
** the CREATE TABLE or CREATE INDEX statement is replaced with the third
** argument and the result returned. Examples:
**
** sqlite_rename_table('CREATE TABLE abc(a, b, c)', 'def')
** -> 'CREATE TABLE def(a, b, c)'
**
** sqlite_rename_table('CREATE INDEX i ON abc(a)', 'def')
** -> 'CREATE INDEX i ON def(a, b, c)'
*/
static void renameTableFunc(
sqlite3_context *context,
int NotUsed,
sqlite3_value **argv
){
unsigned char const *zSql = sqlite3_value_text(argv[0]);
unsigned char const *zTableName = sqlite3_value_text(argv[1]);
int token;
Token tname;
unsigned char const *zCsr = zSql;
int len = 0;
char *zRet;
sqlite3 *db = sqlite3_context_db_handle(context);
UNUSED_PARAMETER(NotUsed);
/* The principle used to locate the table name in the CREATE TABLE
** statement is that the table name is the first non-space token that
** is immediately followed by a TK_LP or TK_USING token.
*/
if( zSql ){
do {
if( !*zCsr ){
/* Ran out of input before finding an opening bracket. Return NULL. */
return;
}
/* Store the token that zCsr points to in tname. */
tname.z = (char*)zCsr;
tname.n = len;
/* Advance zCsr to the next token. Store that token type in 'token',
** and its length in 'len' (to be used next iteration of this loop).
*/
do {
zCsr += len;
len = sqlite3GetToken(zCsr, &token);
} while( token==TK_SPACE );
assert( len>0 );
} while( token!=TK_LP && token!=TK_USING );
zRet = sqlite3MPrintf(db, "%.*s\"%w\"%s", ((u8*)tname.z) - zSql, zSql,
zTableName, tname.z+tname.n);
sqlite3_result_text(context, zRet, -1, SQLITE_DYNAMIC);
}
}
/*
** This C function implements an SQL user function that is used by SQL code
** generated by the ALTER TABLE ... RENAME command to modify the definition
** of any foreign key constraints that use the table being renamed as the
** parent table. It is passed three arguments:
**
** 1) The complete text of the CREATE TABLE statement being modified,
** 2) The old name of the table being renamed, and
** 3) The new name of the table being renamed.
**
** It returns the new CREATE TABLE statement. For example:
**
** sqlite_rename_parent('CREATE TABLE t1(a REFERENCES t2)', 't2', 't3')
** -> 'CREATE TABLE t1(a REFERENCES t3)'
*/
#ifndef SQLITE_OMIT_FOREIGN_KEY
static void renameParentFunc(
sqlite3_context *context,
int NotUsed,
sqlite3_value **argv
){
sqlite3 *db = sqlite3_context_db_handle(context);
char *zOutput = 0;
char *zResult;
unsigned char const *zInput = sqlite3_value_text(argv[0]);
unsigned char const *zOld = sqlite3_value_text(argv[1]);
unsigned char const *zNew = sqlite3_value_text(argv[2]);
unsigned const char *z; /* Pointer to token */
int n; /* Length of token z */
int token; /* Type of token */
UNUSED_PARAMETER(NotUsed);
for(z=zInput; *z; z=z+n){
n = sqlite3GetToken(z, &token);
if( token==TK_REFERENCES ){
char *zParent;
do {
z += n;
n = sqlite3GetToken(z, &token);
}while( token==TK_SPACE );
zParent = sqlite3DbStrNDup(db, (const char *)z, n);
if( zParent==0 ) break;
sqlite3Dequote(zParent);
if( 0==sqlite3StrICmp((const char *)zOld, zParent) ){
char *zOut = sqlite3MPrintf(db, "%s%.*s\"%w\"",
(zOutput?zOutput:""), z-zInput, zInput, (const char *)zNew
);
sqlite3DbFree(db, zOutput);
zOutput = zOut;
zInput = &z[n];
}
sqlite3DbFree(db, zParent);
}
}
zResult = sqlite3MPrintf(db, "%s%s", (zOutput?zOutput:""), zInput),
sqlite3_result_text(context, zResult, -1, SQLITE_DYNAMIC);
sqlite3DbFree(db, zOutput);
}
#endif
#ifndef SQLITE_OMIT_TRIGGER
/* This function is used by SQL generated to implement the
** ALTER TABLE command. The first argument is the text of a CREATE TRIGGER
** statement. The second is a table name. The table name in the CREATE
** TRIGGER statement is replaced with the third argument and the result
** returned. This is analagous to renameTableFunc() above, except for CREATE
** TRIGGER, not CREATE INDEX and CREATE TABLE.
*/
static void renameTriggerFunc(
sqlite3_context *context,
int NotUsed,
sqlite3_value **argv
){
unsigned char const *zSql = sqlite3_value_text(argv[0]);
unsigned char const *zTableName = sqlite3_value_text(argv[1]);
int token;
Token tname;
int dist = 3;
unsigned char const *zCsr = zSql;
int len = 0;
char *zRet;
sqlite3 *db = sqlite3_context_db_handle(context);
UNUSED_PARAMETER(NotUsed);
/* The principle used to locate the table name in the CREATE TRIGGER
** statement is that the table name is the first token that is immediatedly
** preceded by either TK_ON or TK_DOT and immediatedly followed by one
** of TK_WHEN, TK_BEGIN or TK_FOR.
*/
if( zSql ){
do {
if( !*zCsr ){
/* Ran out of input before finding the table name. Return NULL. */
return;
}
/* Store the token that zCsr points to in tname. */
tname.z = (char*)zCsr;
tname.n = len;
/* Advance zCsr to the next token. Store that token type in 'token',
** and its length in 'len' (to be used next iteration of this loop).
*/
do {
zCsr += len;
len = sqlite3GetToken(zCsr, &token);
}while( token==TK_SPACE );
assert( len>0 );
/* Variable 'dist' stores the number of tokens read since the most
** recent TK_DOT or TK_ON. This means that when a WHEN, FOR or BEGIN
** token is read and 'dist' equals 2, the condition stated above
** to be met.
**
** Note that ON cannot be a database, table or column name, so
** there is no need to worry about syntax like
** "CREATE TRIGGER ... ON ON.ON BEGIN ..." etc.
*/
dist++;
if( token==TK_DOT || token==TK_ON ){
dist = 0;
}
} while( dist!=2 || (token!=TK_WHEN && token!=TK_FOR && token!=TK_BEGIN) );
/* Variable tname now contains the token that is the old table-name
** in the CREATE TRIGGER statement.
*/
zRet = sqlite3MPrintf(db, "%.*s\"%w\"%s", ((u8*)tname.z) - zSql, zSql,
zTableName, tname.z+tname.n);
sqlite3_result_text(context, zRet, -1, SQLITE_DYNAMIC);
}
}
#endif /* !SQLITE_OMIT_TRIGGER */
/*
** Register built-in functions used to help implement ALTER TABLE
*/
void sqlite3AlterFunctions(void){
static SQLITE_WSD FuncDef aAlterTableFuncs[] = {
FUNCTION(sqlite_rename_table, 2, 0, 0, renameTableFunc),
#ifndef SQLITE_OMIT_TRIGGER
FUNCTION(sqlite_rename_trigger, 2, 0, 0, renameTriggerFunc),
#endif
#ifndef SQLITE_OMIT_FOREIGN_KEY
FUNCTION(sqlite_rename_parent, 3, 0, 0, renameParentFunc),
#endif
};
int i;
FuncDefHash *pHash = &GLOBAL(FuncDefHash, sqlite3GlobalFunctions);
FuncDef *aFunc = (FuncDef*)&GLOBAL(FuncDef, aAlterTableFuncs);
for(i=0; i<ArraySize(aAlterTableFuncs); i++){
sqlite3FuncDefInsert(pHash, &aFunc[i]);
}
}
/*
** This function is used to create the text of expressions of the form:
**
** name=<constant1> OR name=<constant2> OR ...
**
** If argument zWhere is NULL, then a pointer string containing the text
** "name=<constant>" is returned, where <constant> is the quoted version
** of the string passed as argument zConstant. The returned buffer is
** allocated using sqlite3DbMalloc(). It is the responsibility of the
** caller to ensure that it is eventually freed.
**
** If argument zWhere is not NULL, then the string returned is
** "<where> OR name=<constant>", where <where> is the contents of zWhere.
** In this case zWhere is passed to sqlite3DbFree() before returning.
**
*/
static char *whereOrName(sqlite3 *db, char *zWhere, char *zConstant){
char *zNew;
if( !zWhere ){
zNew = sqlite3MPrintf(db, "name=%Q", zConstant);
}else{
zNew = sqlite3MPrintf(db, "%s OR name=%Q", zWhere, zConstant);
sqlite3DbFree(db, zWhere);
}
return zNew;
}
#if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
/*
** Generate the text of a WHERE expression which can be used to select all
** tables that have foreign key constraints that refer to table pTab (i.e.
** constraints for which pTab is the parent table) from the sqlite_master
** table.
*/
static char *whereForeignKeys(Parse *pParse, Table *pTab){
FKey *p;
char *zWhere = 0;
for(p=sqlite3FkReferences(pTab); p; p=p->pNextTo){
zWhere = whereOrName(pParse->db, zWhere, p->pFrom->zName);
}
return zWhere;
}
#endif
/*
** Generate the text of a WHERE expression which can be used to select all
** temporary triggers on table pTab from the sqlite_temp_master table. If
** table pTab has no temporary triggers, or is itself stored in the
** temporary database, NULL is returned.
*/
static char *whereTempTriggers(Parse *pParse, Table *pTab){
Trigger *pTrig;
char *zWhere = 0;
const Schema *pTempSchema = pParse->db->aDb[1].pSchema; /* Temp db schema */
/* If the table is not located in the temp-db (in which case NULL is
** returned, loop through the tables list of triggers. For each trigger
** that is not part of the temp-db schema, add a clause to the WHERE
** expression being built up in zWhere.
*/
if( pTab->pSchema!=pTempSchema ){
sqlite3 *db = pParse->db;
for(pTrig=sqlite3TriggerList(pParse, pTab); pTrig; pTrig=pTrig->pNext){
if( pTrig->pSchema==pTempSchema ){
zWhere = whereOrName(db, zWhere, pTrig->zName);
}
}
}
if( zWhere ){
char *zNew = sqlite3MPrintf(pParse->db, "type='trigger' AND (%s)", zWhere);
sqlite3DbFree(pParse->db, zWhere);
zWhere = zNew;
}
return zWhere;
}
/*
** Generate code to drop and reload the internal representation of table
** pTab from the database, including triggers and temporary triggers.
** Argument zName is the name of the table in the database schema at
** the time the generated code is executed. This can be different from
** pTab->zName if this function is being called to code part of an
** "ALTER TABLE RENAME TO" statement.
*/
static void reloadTableSchema(Parse *pParse, Table *pTab, const char *zName){
Vdbe *v;
char *zWhere;
int iDb; /* Index of database containing pTab */
#ifndef SQLITE_OMIT_TRIGGER
Trigger *pTrig;
#endif
v = sqlite3GetVdbe(pParse);
if( NEVER(v==0) ) return;
assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
assert( iDb>=0 );
#ifndef SQLITE_OMIT_TRIGGER
/* Drop any table triggers from the internal schema. */
for(pTrig=sqlite3TriggerList(pParse, pTab); pTrig; pTrig=pTrig->pNext){
int iTrigDb = sqlite3SchemaToIndex(pParse->db, pTrig->pSchema);
assert( iTrigDb==iDb || iTrigDb==1 );
sqlite3VdbeAddOp4(v, OP_DropTrigger, iTrigDb, 0, 0, pTrig->zName, 0);
}
#endif
/* Drop the table and index from the internal schema. */
sqlite3VdbeAddOp4(v, OP_DropTable, iDb, 0, 0, pTab->zName, 0);
/* Reload the table, index and permanent trigger schemas. */
zWhere = sqlite3MPrintf(pParse->db, "tbl_name=%Q", zName);
if( !zWhere ) return;
sqlite3VdbeAddOp4(v, OP_ParseSchema, iDb, 0, 0, zWhere, P4_DYNAMIC);
#ifndef SQLITE_OMIT_TRIGGER
/* Now, if the table is not stored in the temp database, reload any temp
** triggers. Don't use IN(...) in case SQLITE_OMIT_SUBQUERY is defined.
*/
if( (zWhere=whereTempTriggers(pParse, pTab))!=0 ){
sqlite3VdbeAddOp4(v, OP_ParseSchema, 1, 0, 0, zWhere, P4_DYNAMIC);
}
#endif
}
/*
** 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( sqlite3Strlen30(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_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 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;
}
/*
** Generate code to make sure the file format number is at least minFormat.
** The generated code will increase the file format number if necessary.
*/
void sqlite3MinimumFileFormat(Parse *pParse, int iDb, int minFormat){
Vdbe *v;
v = sqlite3GetVdbe(pParse);
/* The VDBE should have been allocated before this routine is called.
** If that allocation failed, we would have quit before reaching this
** point */
if( ALWAYS(v) ){
int r1 = sqlite3GetTempReg(pParse);
int r2 = sqlite3GetTempReg(pParse);
int j1;
sqlite3VdbeAddOp3(v, OP_ReadCookie, iDb, r1, BTREE_FILE_FORMAT);
sqlite3VdbeUsesBtree(v, iDb);
sqlite3VdbeAddOp2(v, OP_Integer, minFormat, r2);
j1 = sqlite3VdbeAddOp3(v, OP_Ge, r2, 0, r1);
sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, BTREE_FILE_FORMAT, r2);
sqlite3VdbeJumpHere(v, j1);
sqlite3ReleaseTempReg(pParse, r1);
sqlite3ReleaseTempReg(pParse, r2);
}
}
/*
** 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; */
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 */
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->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.)
*/
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. */
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.
*/
sqlite3MinimumFileFormat(pParse, iDb, pDflt ? 3 : 2);
/* Reload the schema of the modified table. */
reloadTableSchema(pParse, pTab, pTab->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->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;
pCol->zDflt = 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;
}
#endif /* SQLITE_ALTER_TABLE */