/*
** 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.
**
** $Id: alter.c,v 1.2 2005/02/15 21:36:18 drh Exp $
*/
#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 second
** 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 argc,
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;
char const *zCsr = zSql;
int len = 0;
char *zRet;
/* The principle used to locate the table name in the CREATE TABLE
** statement is that the table name is the first token that is immediatedly
** followed by a left parenthesis - TK_LP.
*/
if( zSql ){
do {
/* Store the token that zCsr points to in tname. */
tname.z = zCsr;
tname.n = len;
/* Advance zCsr to the next token. Store that token type in 'token',
** and it's 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 );
zRet = sqlite3MPrintf("%.*s%Q%s", tname.z - zSql, zSql,
zTableName, tname.z+tname.n);
sqlite3_result_text(context, zRet, -1, sqlite3FreeX);
}
}
#ifndef SQLITE_OMIT_TRIGGER
/* This function is used by SQL generated to implement the ALTER TABLE
** 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 second 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 argc,
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;
char const *zCsr = zSql;
int len = 0;
char *zRet;
/* 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 {
/* Store the token that zCsr points to in tname. */
tname.z = zCsr;
tname.n = len;
/* Advance zCsr to the next token. Store that token type in 'token',
** and it's 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("%.*s%Q%s", tname.z - zSql, zSql,
zTableName, tname.z+tname.n);
sqlite3_result_text(context, zRet, -1, sqlite3FreeX);
}
}
#endif /* !SQLITE_OMIT_TRIGGER */
/*
** Register built-in functions used to help implement ALTER TABLE
*/
void sqlite3AlterFunctions(sqlite3 *db){
static const struct {
char *zName;
signed char nArg;
void (*xFunc)(sqlite3_context*,int,sqlite3_value **);
} aFuncs[] = {
{ "sqlite_rename_table", 2, renameTableFunc},
#ifndef SQLITE_OMIT_TRIGGER
{ "sqlite_rename_trigger", 2, renameTriggerFunc},
#endif
};
int i;
for(i=0; i<sizeof(aFuncs)/sizeof(aFuncs[0]); i++){
sqlite3_create_function(db, aFuncs[i].zName, aFuncs[i].nArg,
SQLITE_UTF8, 0, aFuncs[i].xFunc, 0, 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 */
char *zWhere = 0; /* Where clause of schema elements to reparse */
sqlite3 *db = pParse->db; /* Database connection */
Vdbe *v;
#ifndef SQLITE_OMIT_TRIGGER
char *zTempTrig = 0; /* Where clause to locate temp triggers */
#endif
assert( pSrc->nSrc==1 );
pTab = sqlite3LocateTable(pParse, pSrc->a[0].zName, pSrc->a[0].zDatabase);
if( !pTab ) goto exit_rename_table;
iDb = pTab->iDb;
zDb = db->aDb[iDb].zName;
/* Get a NULL terminated version of the new table name. */
zName = sqlite3NameFromToken(pName);
if( !zName ) goto exit_rename_table;
/* Check that a table or index named 'zName' does not already exist
** in database iDb. If so, this is an error.
*/
if( sqlite3FindTable(db, zName, zDb) || sqlite3FindIndex(db, zName, zDb) ){
sqlite3ErrorMsg(pParse,
"there is already another table or index with this name: %s", zName);
goto exit_rename_table;
}
/* Make sure it is not a system table being altered, or a reserved name
** that the table is being renamed to.
*/
if( strlen(pTab->zName)>6 && 0==sqlite3StrNICmp(pTab->zName, "sqlite_", 7) ){
sqlite3ErrorMsg(pParse, "table %s may not be altered", pTab->zName);
goto exit_rename_table;
}
if( SQLITE_OK!=sqlite3CheckObjectName(pParse, zName) ){
goto exit_rename_table;
}
#ifndef SQLITE_OMIT_AUTHORIZATION
/* Invoke the authorization callback. */
if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab->zName, 0) ){
goto exit_rename_table;
}
#endif
/* Begin a transaction and code the VerifyCookie for database iDb.
** Then modify the schema cookie (since the ALTER TABLE modifies the
** schema).
*/
v = sqlite3GetVdbe(pParse);
if( v==0 ){
goto exit_rename_table;
}
sqlite3BeginWriteOperation(pParse, 0, iDb);
sqlite3ChangeCookie(db, v, iDb);
/* Modify the sqlite_master table to use the new table name. */
sqlite3NestedParse(pParse,
"UPDATE %Q.%s SET "
#ifdef SQLITE_OMIT_TRIGGER
"sql = sqlite_rename_table(sql, %Q), "
#else
"sql = CASE "
"WHEN type = 'trigger' THEN sqlite_rename_trigger(sql, %Q)"
"ELSE sqlite_rename_table(sql, %Q) END, "
#endif
"tbl_name = %Q, "
"name = CASE "
"WHEN type='table' THEN %Q "
"WHEN name LIKE 'sqlite_autoindex%%' AND type='index' THEN "
"'sqlite_autoindex_' || %Q || substr(name, %d+18,10) "
"ELSE name END "
"WHERE tbl_name=%Q AND "
"(type='table' OR type='index' OR type='trigger');",
zDb, SCHEMA_TABLE(iDb), zName, zName, zName,
#ifndef SQLITE_OMIT_TRIGGER
zName,
#endif
zName, strlen(pTab->zName), pTab->zName
);
#ifndef SQLITE_OMIT_AUTOINCREMENT
/* If the sqlite_sequence table exists in this database, then update
** it with the new table name.
*/
if( sqlite3FindTable(db, "sqlite_sequence", zDb) ){
sqlite3NestedParse(pParse,
"UPDATE %Q.sqlite_sequence set name = %Q WHERE name = %Q",
zDb, zName, pTab->zName);
}
#endif
#ifndef SQLITE_OMIT_TRIGGER
/* If there are TEMP triggers on this table, modify the sqlite_temp_master
** table. Don't do this if the table being ALTERed is itself located in
** the temp database.
*/
if( iDb!=1 ){
Trigger *pTrig;
char *tmp = 0;
for( pTrig=pTab->pTrigger; pTrig; pTrig=pTrig->pNext ){
if( pTrig->iDb==1 ){
if( !zTempTrig ){
zTempTrig =
sqlite3MPrintf("type = 'trigger' AND (name=%Q", pTrig->name);
}else{
tmp = zTempTrig;
zTempTrig = sqlite3MPrintf("%s OR name=%Q", zTempTrig, pTrig->name);
sqliteFree(tmp);
}
}
}
if( zTempTrig ){
tmp = zTempTrig;
zTempTrig = sqlite3MPrintf("%s)", zTempTrig);
sqliteFree(tmp);
sqlite3NestedParse(pParse,
"UPDATE sqlite_temp_master SET "
"sql = sqlite_rename_trigger(sql, %Q), "
"tbl_name = %Q "
"WHERE %s;", zName, zName, zTempTrig);
}
}
#endif
/* Drop the elements of the in-memory schema that refered to the table
** renamed and load the new versions from the database.
*/
if( pParse->nErr==0 ){
#ifndef SQLITE_OMIT_TRIGGER
Trigger *pTrig;
for( pTrig=pTab->pTrigger; pTrig; pTrig=pTrig->pNext ){
assert( pTrig->iDb==iDb || pTrig->iDb==1 );
sqlite3VdbeOp3(v, OP_DropTrigger, pTrig->iDb, 0, pTrig->name, 0);
}
#endif
sqlite3VdbeOp3(v, OP_DropTable, iDb, 0, pTab->zName, 0);
zWhere = sqlite3MPrintf("tbl_name=%Q", zName);
sqlite3VdbeOp3(v, OP_ParseSchema, iDb, 0, zWhere, P3_DYNAMIC);
#ifndef SQLITE_OMIT_TRIGGER
if( zTempTrig ){
sqlite3VdbeOp3(v, OP_ParseSchema, 1, 0, zTempTrig, P3_DYNAMIC);
}
}else{
sqliteFree(zTempTrig);
#endif
}
exit_rename_table:
sqlite3SrcListDelete(pSrc);
sqliteFree(zName);
}
#endif /* SQLITE_ALTER_TABLE */