/* ** 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 1.1.1.1 2006/02/03 20:35:16 hoganrobert Exp $ */ #include "sqliteInt.h" #include /* ** 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; iiDb!=1 ){ for( pTrig=pTab->pTrigger; pTrig; pTrig=pTrig->pNext ){ if( pTrig->iDb==1 ){ if( !zWhere ){ zWhere = sqlite3MPrintf("name=%Q", pTrig->name); }else{ tmp = zWhere; zWhere = sqlite3MPrintf("%s OR name=%Q", zWhere, pTrig->name); sqliteFree(tmp); } } } } 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; #ifndef SQLITE_OMIT_TRIGGER Trigger *pTrig; #endif v = sqlite3GetVdbe(pParse); if( !v ) return; iDb = pTab->iDb; #ifndef SQLITE_OMIT_TRIGGER /* Drop any table triggers from the internal schema. */ 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 /* Drop the table and index from the internal schema */ sqlite3VdbeOp3(v, OP_DropTable, iDb, 0, pTab->zName, 0); /* Reload the table, index and permanent trigger schemas. */ zWhere = sqlite3MPrintf("tbl_name=%Q", zName); if( !zWhere ) return; sqlite3VdbeOp3(v, OP_ParseSchema, iDb, 0, zWhere, P3_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)) ){ sqlite3VdbeOp3(v, OP_ParseSchema, 1, 0, zWhere, P3_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 */ Vdbe *v; #ifndef SQLITE_OMIT_TRIGGER char *zWhere = 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( (zWhere=whereTempTriggers(pParse, pTab)) ){ sqlite3NestedParse(pParse, "UPDATE sqlite_temp_master SET " "sql = sqlite_rename_trigger(sql, %Q), " "tbl_name = %Q " "WHERE %s;", zName, zName, zWhere); sqliteFree(zWhere); } #endif /* Drop and reload the internal table schema. */ reloadTableSchema(pParse, pTab, zName); exit_rename_table: sqlite3SrcListDelete(pSrc); sqliteFree(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 */ Vdbe *v; if( pParse->nErr ) return; pNew = pParse->pNewTable; assert( pNew ); iDb = pNew->iDb; 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 ); /* 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(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. */ if( (v=sqlite3GetVdbe(pParse)) ){ int f = (pDflt?3:2); /* Only set the file format to $f if it is currently less than $f. */ sqlite3VdbeAddOp(v, OP_ReadCookie, iDb, 1); sqlite3VdbeAddOp(v, OP_Integer, f, 0); sqlite3VdbeAddOp(v, OP_Ge, 0, sqlite3VdbeCurrentAddr(v)+3); sqlite3VdbeAddOp(v, OP_Integer, f, 0); sqlite3VdbeAddOp(v, OP_SetCookie, iDb, 1); } /* 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 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; /* Look up the table being altered. */ assert( !pParse->pNewTable ); pTab = sqlite3LocateTable(pParse, pSrc->a[0].zName, pSrc->a[0].zDatabase); if( !pTab ) goto exit_begin_add_column; /* 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 = pTab->iDb; /* Put a copy of the Table struct in Parse.pNewTable for the ** sqlite3AddColumn() function and friends to modify. */ pNew = (Table *)sqliteMalloc(sizeof(Table)); if( !pNew ) goto exit_begin_add_column; pParse->pNewTable = pNew; 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 *)sqliteMalloc(sizeof(Column)*nAlloc); pNew->zName = sqliteStrDup(pTab->zName); if( !pNew->aCol || !pNew->zName ){ goto exit_begin_add_column; } memcpy(pNew->aCol, pTab->aCol, sizeof(Column)*pNew->nCol); for(i=0; inCol; i++){ Column *pCol = &pNew->aCol[i]; pCol->zName = sqliteStrDup(pCol->zName); pCol->zType = 0; pCol->pDflt = 0; } pNew->iDb = iDb; 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->db, v, iDb); exit_begin_add_column: sqlite3SrcListDelete(pSrc); return; } #endif /* SQLITE_ALTER_TABLE */