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1595abcda65adeaf8bddaba36d133b414ff86cdf
sqlite/src/alter.c
drh 1595abcda6 Improved error messages when an ALTER TABLE RENAME COLUMN fails due to a 
duplicate column name.

FossilOrigin-Name: 37d11b8e8224a8b241ff57b9c4b9499db39dde4ddcb56ff8b03a3d08091a4c11
2018-08-14 19:27:51 +00:00

1208 lines
39 KiB
C
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/*
** 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 || !*zCsr );
} while( token!=TK_LP && token!=TK_USING );
zRet = sqlite3MPrintf(db, "%.*s\"%w\"%s", (int)(((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);
if( zInput==0 || zOld==0 ) return;
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 );
if( token==TK_ILLEGAL ) break;
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:""), (int)(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 immediately
** preceded by either TK_ON or TK_DOT and immediately 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 || !*zCsr );
/* 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", (int)(((u8*)tname.z) - zSql),
zSql, zTableName, tname.z+tname.n);
sqlite3_result_text(context, zRet, -1, SQLITE_DYNAMIC);
}
}
#endif /* !SQLITE_OMIT_TRIGGER */
/*
** 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;
sqlite3VdbeAddParseSchemaOp(v, iDb, zWhere);
#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 ){
sqlite3VdbeAddParseSchemaOp(v, 1, zWhere);
}
#endif
}
/*
** Parameter zName is the name of a table that is about to be altered
** (either with ALTER TABLE ... RENAME TO or ALTER TABLE ... ADD COLUMN).
** If the table is a system table, this function leaves an error message
** in pParse->zErr (system tables may not be altered) and returns non-zero.
**
** Or, if zName is not a system table, zero is returned.
*/
static int isSystemTable(Parse *pParse, const char *zName){
if( 0==sqlite3StrNICmp(zName, "sqlite_", 7) ){
sqlite3ErrorMsg(pParse, "table %s may not be altered", zName);
return 1;
}
return 0;
}
/*
** 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() */
u32 savedDbFlags; /* Saved value of db->mDbFlags */
savedDbFlags = db->mDbFlags;
if( NEVER(db->mallocFailed) ) goto exit_rename_table;
assert( pSrc->nSrc==1 );
assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
pTab = sqlite3LocateTableItem(pParse, 0, &pSrc->a[0]);
if( !pTab ) goto exit_rename_table;
iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
zDb = db->aDb[iDb].zDbSName;
db->mDbFlags |= DBFLAG_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 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;
sqlite3VdbeLoadString(v, i, zName);
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, MASTER_NAME, 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, MASTER_NAME, 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->mDbFlags = savedDbFlags;
}
/*
** 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 */
int r1; /* Temporary registers */
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].zDbSName;
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.
*/
assert( pDflt==0 || pDflt->op==TK_SPAN );
if( pDflt && pDflt->pLeft->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];
u32 savedDbFlags = db->mDbFlags;
while( zEnd>zCol && (*zEnd==';' || sqlite3Isspace(*zEnd)) ){
*zEnd-- = '\0';
}
db->mDbFlags |= DBFLAG_PreferBuiltin;
sqlite3NestedParse(pParse,
"UPDATE \"%w\".%s SET "
"sql = substr(sql,1,%d) || ', ' || %Q || substr(sql,%d) "
"WHERE type = 'table' AND name = %Q",
zDb, MASTER_NAME, pNew->addColOffset, zCol, pNew->addColOffset+1,
zTab
);
sqlite3DbFree(db, zCol);
db->mDbFlags = savedDbFlags;
}
/* Make sure the schema version is at least 3. But do not upgrade
** from less than 3 to 4, as that will corrupt any preexisting DESC
** index.
*/
r1 = sqlite3GetTempReg(pParse);
sqlite3VdbeAddOp3(v, OP_ReadCookie, iDb, r1, BTREE_FILE_FORMAT);
sqlite3VdbeUsesBtree(v, iDb);
sqlite3VdbeAddOp2(v, OP_AddImm, r1, -2);
sqlite3VdbeAddOp2(v, OP_IfPos, r1, sqlite3VdbeCurrentAddr(v)+2);
VdbeCoverage(v);
sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, BTREE_FILE_FORMAT, 3);
sqlite3ReleaseTempReg(pParse, r1);
/* 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 = sqlite3LocateTableItem(pParse, 0, &pSrc->a[0]);
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;
}
if( SQLITE_OK!=isSystemTable(pParse, pTab->zName) ){
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->nTabRef = 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 ){
assert( db->mallocFailed );
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->pDflt = 0;
}
pNew->pSchema = db->aDb[iDb].pSchema;
pNew->addColOffset = pTab->addColOffset;
pNew->nTabRef = 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;
}
/*
** Handles the following parser reduction:
**
** cmd ::= ALTER TABLE pSrc RENAME COLUMN pOld TO pNew
*/
void sqlite3AlterRenameColumn(
Parse *pParse, /* Parsing context */
SrcList *pSrc, /* Table being altered. pSrc->nSrc==1 */
Token *pOld, /* Name of column being changed */
Token *pNew /* New column name */
){
sqlite3 *db = pParse->db; /* Database connection */
Table *pTab; /* Table being updated */
int iCol; /* Index of column being renamed */
char *zOld = 0; /* Old column name */
char *zNew = 0; /* New column name */
const char *zDb; /* Name of schema containing the table */
int iSchema; /* Index of the schema */
int bQuote; /* True to quote the new name */
/* Locate the table to be altered */
pTab = sqlite3LocateTableItem(pParse, 0, &pSrc->a[0]);
if( !pTab ) goto exit_rename_column;
/* Cannot alter a system table */
if( SQLITE_OK!=isSystemTable(pParse, pTab->zName) ) goto exit_rename_column;
/* Which schema holds the table to be altered */
iSchema = sqlite3SchemaToIndex(db, pTab->pSchema);
assert( iSchema>=0 );
zDb = db->aDb[iSchema].zDbSName;
/* Make sure the old name really is a column name in the table to be
** altered. Set iCol to be the index of the column being renamed */
zOld = sqlite3NameFromToken(db, pOld);
if( !zOld ) goto exit_rename_column;
for(iCol=0; iCol<pTab->nCol; iCol++){
if( 0==sqlite3StrICmp(pTab->aCol[iCol].zName, zOld) ) break;
}
if( iCol==pTab->nCol ){
sqlite3ErrorMsg(pParse, "no such column: \"%s\"", zOld);
goto exit_rename_column;
}
/* Do the rename operation using a recursive UPDATE statement that
** uses the sqlite_rename_column() SQL function to compute the new
** CREATE statement text for the sqlite_master table.
*/
zNew = sqlite3NameFromToken(db, pNew);
if( !zNew ) goto exit_rename_column;
assert( pNew->n>0 );
bQuote = sqlite3Isquote(pNew->z[0]);
sqlite3NestedParse(pParse,
"UPDATE \"%w\".%s SET "
"sql = sqlite_rename_column(sql, %d, %d, %Q, %Q, %Q) "
"WHERE name NOT LIKE 'sqlite_%%' AND ("
" type = 'table' OR (type='index' AND tbl_name = %Q)"
")",
zDb, MASTER_NAME, iCol, bQuote, zNew, pTab->zName, zOld, pTab->zName
);
/* Drop and reload the database schema. */
if( pParse->pVdbe ){
sqlite3ChangeCookie(pParse, iSchema);
sqlite3VdbeAddParseSchemaOp(pParse->pVdbe, iSchema, 0);
}
exit_rename_column:
sqlite3SrcListDelete(db, pSrc);
sqlite3DbFree(db, zOld);
sqlite3DbFree(db, zNew);
return;
}
/*
** Each RenameToken object maps an element of the parse tree into
** the token that generated that element. The parse tree element
** might be one of:
**
** * A pointer to an Expr that represents an ID
** * The name of a table column in Column.zName
**
** A list of RenameToken objects can be constructed during parsing.
** Each new object is created by sqlite3RenameToken().
** As the parse tree is transformed, the sqlite3MoveRenameToken()
** routine is used to keep the mapping current.
**
** After the parse finishes, renameTokenFind() routine can be used
** to look up the actual token value that created some element in
** the parse tree.
*/
struct RenameToken {
void *p; /* Parse tree element created by token t */
Token t; /* The token that created parse tree element p */
RenameToken *pNext; /* Next is a list of all RenameToken objects */
};
/*
** The context of an ALTER TABLE RENAME COLUMN operation that gets passed
** down into the Walker.
*/
struct RenameCtx {
RenameToken *pList; /* List of tokens to overwrite */
int nList; /* Number of tokens in pList */
int iCol; /* Index of column being renamed */
};
/*
** Add a new RenameToken object mapping parse tree element pPtr into
** token *pToken to the Parse object currently under construction.
*/
void sqlite3RenameToken(Parse *pParse, void *pPtr, Token *pToken){
RenameToken *pNew;
pNew = sqlite3DbMallocZero(pParse->db, sizeof(RenameToken));
if( pNew ){
pNew->p = pPtr;
pNew->t = *pToken;
pNew->pNext = pParse->pRename;
pParse->pRename = pNew;
}
}
/*
** If there is a RenameToken object associated with parse tree element
** pFrom, then remap that object over to pTo due to a transformation
** in the parse tree.
*/
void sqlite3MoveRenameToken(Parse *pParse, void *pTo, void *pFrom){
RenameToken *p;
for(p=pParse->pRename; p; p=p->pNext){
if( p->p==pFrom ){
p->p = pTo;
break;
}
}
assert( p );
}
/*
** Free the list of RenameToken objects given in the second argument
*/
static void renameTokenFree(sqlite3 *db, RenameToken *pToken){
RenameToken *pNext;
RenameToken *p;
for(p=pToken; p; p=pNext){
pNext = p->pNext;
sqlite3DbFree(db, p);
}
}
/*
** Search the Parse object passed as the first argument for a RenameToken
** object associated with parse tree element pPtr. If found, remove it
** from the Parse object and add it to the list maintained by the
** RenameCtx object passed as the second argument.
*/
static void renameTokenFind(Parse *pParse, struct RenameCtx *pCtx, void *pPtr){
RenameToken **pp;
for(pp=&pParse->pRename; (*pp); pp=&(*pp)->pNext){
if( (*pp)->p==pPtr ){
RenameToken *pToken = *pp;
*pp = pToken->pNext;
pToken->pNext = pCtx->pList;
pCtx->pList = pToken;
pCtx->nList++;
break;
}
}
}
/*
** This is a Walker expression callback.
**
** For every TK_COLUMN node in the expression tree, search to see
** if the column being references is the column being renamed by an
** ALTER TABLE statement. If it is, then attach its associated
** RenameToken object to the list of RenameToken objects being
** constructed in RenameCtx object at pWalker->u.pRename.
*/
static int renameColumnExprCb(Walker *pWalker, Expr *pExpr){
struct RenameCtx *p = pWalker->u.pRename;
if( pExpr->op==TK_COLUMN && pExpr->iColumn==p->iCol ){
renameTokenFind(pWalker->pParse, p, (void*)pExpr);
}
return WRC_Continue;
}
/*
** The RenameCtx contains a list of tokens that reference a column that
** is being renamed by an ALTER TABLE statement. Return the "first"
** RenameToken in the RenameCtx and remove that RenameToken from the
** RenameContext. "First" means the first RenameToken encountered when
** the input SQL from left to right. Repeated calls to this routine
** return all column name tokens in the order that they are encountered
** in the SQL statement.
*/
static RenameToken *renameColumnTokenNext(struct RenameCtx *pCtx){
RenameToken *pBest = pCtx->pList;
RenameToken *pToken;
RenameToken **pp;
for(pToken=pBest->pNext; pToken; pToken=pToken->pNext){
if( pToken->t.z>pBest->t.z ) pBest = pToken;
}
for(pp=&pCtx->pList; *pp!=pBest; pp=&(*pp)->pNext);
*pp = pBest->pNext;
return pBest;
}
/*
** SQL function:
**
** sqlite_rename_column(zSql, iCol, bQuote, zNew, zTable, zOld)
**
** Do a column rename operation on the CREATE statement given in zSql.
** The iCol-th column (left-most is 0) of table zTable is renamed from zCol
** into zNew. The name should be quoted if bQuote is true.
**
** This function is used internally by the ALTER TABLE RENAME COLUMN command.
** Though accessible to application code, it is not intended for use by
** applications. The existance of this function, and the way it works,
** is subject to change without notice.
**
** If any of the parameters are out-of-bounds, then simply return NULL.
** An out-of-bounds parameter can only occur when the application calls
** this function directly. The parameters will always be well-formed when
** this routine is invoked by the bytecode for a legitimate ALTER TABLE
** statement.
*/
static void renameColumnFunc(
sqlite3_context *context,
int NotUsed,
sqlite3_value **argv
){
sqlite3 *db = sqlite3_context_db_handle(context);
struct RenameCtx sCtx;
const char *zSql = (const char*)sqlite3_value_text(argv[0]);
int nSql = sqlite3_value_bytes(argv[0]);
int bQuote = sqlite3_value_int(argv[2]);
const char *zNew = (const char*)sqlite3_value_text(argv[3]);
int nNew = sqlite3_value_bytes(argv[3]);
const char *zTable = (const char*)sqlite3_value_text(argv[4]);
const char *zOld = (const char*)sqlite3_value_text(argv[5]);
int rc;
char *zErr = 0;
Parse sParse;
Walker sWalker;
Index *pIdx;
char *zOut = 0;
char *zQuot = 0; /* Quoted version of zNew */
int nQuot = 0; /* Length of zQuot in bytes */
int i;
if( zSql==0 ) return;
if( zNew==0 ) return;
if( zTable==0 ) return;
if( zOld==0 ) return;
memset(&sCtx, 0, sizeof(sCtx));
sCtx.iCol = sqlite3_value_int(argv[1]);
if( sCtx.iCol<0 ) return;
memset(&sParse, 0, sizeof(sParse));
sParse.eParseMode = PARSE_MODE_RENAME_COLUMN;
sParse.db = db;
sParse.nQueryLoop = 1;
rc = sqlite3RunParser(&sParse, zSql, &zErr);
assert( sParse.pNewTable==0 || sParse.pNewIndex==0 );
if( db->mallocFailed ) rc = SQLITE_NOMEM;
if( rc==SQLITE_OK && sParse.pNewTable==0 && sParse.pNewIndex==0 ){
rc = SQLITE_CORRUPT_BKPT;
}
if( rc==SQLITE_OK ){
zQuot = sqlite3_mprintf("\"%w\"", zNew);
if( zQuot==0 ){
rc = SQLITE_NOMEM;
}else{
nQuot = sqlite3Strlen30(zQuot);
}
}
if( rc!=SQLITE_OK ){
if( zErr ){
sqlite3_result_error(context, zErr, -1);
}else{
sqlite3_result_error_code(context, rc);
}
sqlite3DbFree(db, zErr);
goto renameColumnFunc_done;
}
if( bQuote ){
zNew = zQuot;
nNew = nQuot;
}
#ifdef SQLITE_DEBUG
assert( sqlite3Strlen30(zSql)==nSql );
{
RenameToken *pToken;
for(pToken=sParse.pRename; pToken; pToken=pToken->pNext){
assert( pToken->t.z>=zSql && &pToken->t.z[pToken->t.n]<=&zSql[nSql] );
}
}
#endif
/* Find tokens that need to be replaced. */
memset(&sWalker, 0, sizeof(Walker));
sWalker.pParse = &sParse;
sWalker.xExprCallback = renameColumnExprCb;
sWalker.u.pRename = &sCtx;
if( sParse.pNewTable ){
int bFKOnly = sqlite3_stricmp(zTable, sParse.pNewTable->zName);
FKey *pFKey;
if( bFKOnly==0 ){
renameTokenFind(
&sParse, &sCtx, (void*)sParse.pNewTable->aCol[sCtx.iCol].zName
);
assert( sCtx.iCol>=0 );
if( sParse.pNewTable->iPKey==sCtx.iCol ){
renameTokenFind(&sParse, &sCtx, (void*)&sParse.pNewTable->iPKey);
sCtx.iCol = -1;
}
sqlite3WalkExprList(&sWalker, sParse.pNewTable->pCheck);
for(pIdx=sParse.pNewTable->pIndex; pIdx; pIdx=pIdx->pNext){
sqlite3WalkExprList(&sWalker, pIdx->aColExpr);
}
}
for(pFKey=sParse.pNewTable->pFKey; pFKey; pFKey=pFKey->pNextFrom){
for(i=0; i<pFKey->nCol; i++){
if( bFKOnly==0 && pFKey->aCol[i].iFrom==sCtx.iCol ){
renameTokenFind(&sParse, &sCtx, (void*)&pFKey->aCol[i]);
}
if( 0==sqlite3_stricmp(pFKey->zTo, zTable)
&& 0==sqlite3_stricmp(pFKey->aCol[i].zCol, zOld)
){
renameTokenFind(&sParse, &sCtx, (void*)pFKey->aCol[i].zCol);
}
}
}
}else{
sqlite3WalkExprList(&sWalker, sParse.pNewIndex->aColExpr);
sqlite3WalkExpr(&sWalker, sParse.pNewIndex->pPartIdxWhere);
}
assert( nQuot>=nNew );
zOut = sqlite3DbMallocZero(db, nSql + sCtx.nList*nQuot + 1);
if( zOut ){
int nOut = nSql;
memcpy(zOut, zSql, nSql);
while( sCtx.pList ){
int iOff; /* Offset of token to replace in zOut */
RenameToken *pBest = renameColumnTokenNext(&sCtx);
int nReplace;
const char *zReplace;
if( sqlite3IsIdChar(*pBest->t.z) ){
nReplace = nNew;
zReplace = zNew;
}else{
nReplace = nQuot;
zReplace = zQuot;
}
iOff = pBest->t.z - zSql;
if( pBest->t.n!=nReplace ){
memmove(&zOut[iOff + nReplace], &zOut[iOff + pBest->t.n],
nOut - (iOff + pBest->t.n)
);
nOut += nReplace - pBest->t.n;
zOut[nOut] = '\0';
}
memcpy(&zOut[iOff], zReplace, nReplace);
sqlite3DbFree(db, pBest);
}
sqlite3_result_text(context, zOut, -1, SQLITE_TRANSIENT);
sqlite3DbFree(db, zOut);
}
renameColumnFunc_done:
if( sParse.pVdbe ){
sqlite3VdbeFinalize(sParse.pVdbe);
}
sqlite3DeleteTable(db, sParse.pNewTable);
if( sParse.pNewIndex ) sqlite3FreeIndex(db, sParse.pNewIndex);
renameTokenFree(db, sParse.pRename);
renameTokenFree(db, sCtx.pList);
sqlite3ParserReset(&sParse);
sqlite3_free(zQuot);
}
/*
** Register built-in functions used to help implement ALTER TABLE
*/
void sqlite3AlterFunctions(void){
static FuncDef aAlterTableFuncs[] = {
FUNCTION(sqlite_rename_table, 2, 0, 0, renameTableFunc),
FUNCTION(sqlite_rename_column, 6, 0, 0, renameColumnFunc),
#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
};
sqlite3InsertBuiltinFuncs(aAlterTableFuncs, ArraySize(aAlterTableFuncs));
}
#endif /* SQLITE_ALTER_TABLE */
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