ds@1952: /*
ds@1952: ** 2005 February 15
ds@1952: **
ds@1952: ** The author disclaims copyright to this source code.  In place of
ds@1952: ** a legal notice, here is a blessing:
ds@1952: **
ds@1952: **    May you do good and not evil.
ds@1952: **    May you find forgiveness for yourself and forgive others.
ds@1952: **    May you share freely, never taking more than you give.
ds@1952: **
ds@1952: *************************************************************************
ds@1952: ** This file contains C code routines that used to generate VDBE code
ds@1952: ** that implements the ALTER TABLE command.
ds@1952: **
ds@1952: ** $Id$
ds@1952: */
ds@1952: #include "sqliteInt.h"
ds@1952: #include <ctype.h>
ds@1952: 
ds@1952: /*
ds@1952: ** The code in this file only exists if we are not omitting the
ds@1952: ** ALTER TABLE logic from the build.
ds@1952: */
ds@1952: #ifndef SQLITE_OMIT_ALTERTABLE
ds@1952: 
ds@1952: 
ds@1952: /*
ds@1952: ** This function is used by SQL generated to implement the 
ds@1952: ** ALTER TABLE command. The first argument is the text of a CREATE TABLE or
ds@1952: ** CREATE INDEX command. The second is a table name. The table name in 
ds@1952: ** the CREATE TABLE or CREATE INDEX statement is replaced with the third
ds@1952: ** argument and the result returned. Examples:
ds@1952: **
ds@1952: ** sqlite_rename_table('CREATE TABLE abc(a, b, c)', 'def')
ds@1952: **     -> 'CREATE TABLE def(a, b, c)'
ds@1952: **
ds@1952: ** sqlite_rename_table('CREATE INDEX i ON abc(a)', 'def')
ds@1952: **     -> 'CREATE INDEX i ON def(a, b, c)'
ds@1952: */
ds@1952: static void renameTableFunc(
ds@1952:   sqlite3_context *context,
ds@1952:   int argc,
ds@1952:   sqlite3_value **argv
ds@1952: ){
ds@1952:   unsigned char const *zSql = sqlite3_value_text(argv[0]);
ds@1952:   unsigned char const *zTableName = sqlite3_value_text(argv[1]);
ds@1952: 
ds@1952:   int token;
ds@1952:   Token tname;
ds@1952:   unsigned char const *zCsr = zSql;
ds@1952:   int len = 0;
ds@1952:   char *zRet;
ds@1952: 
ds@1952:   sqlite3 *db = sqlite3_user_data(context);
ds@1952: 
ds@1952:   /* The principle used to locate the table name in the CREATE TABLE 
ds@1952:   ** statement is that the table name is the first token that is immediatedly
ds@1952:   ** followed by a left parenthesis - TK_LP - or "USING" TK_USING.
ds@1952:   */
ds@1952:   if( zSql ){
ds@1952:     do {
ds@1952:       if( !*zCsr ){
ds@1952:         /* Ran out of input before finding an opening bracket. Return NULL. */
ds@1952:         return;
ds@1952:       }
ds@1952: 
ds@1952:       /* Store the token that zCsr points to in tname. */
ds@1952:       tname.z = zCsr;
ds@1952:       tname.n = len;
ds@1952: 
ds@1952:       /* Advance zCsr to the next token. Store that token type in 'token',
ds@1952:       ** and it's length in 'len' (to be used next iteration of this loop).
ds@1952:       */
ds@1952:       do {
ds@1952:         zCsr += len;
ds@1952:         len = sqlite3GetToken(zCsr, &token);
ds@1952:       } while( token==TK_SPACE );
ds@1952:       assert( len>0 );
ds@1952:     } while( token!=TK_LP && token!=TK_USING );
ds@1952: 
ds@1952:     zRet = sqlite3MPrintf(db, "%.*s%Q%s", tname.z - zSql, zSql, 
ds@1952:        zTableName, tname.z+tname.n);
ds@1952:     sqlite3_result_text(context, zRet, -1, sqlite3_free);
ds@1952:   }
ds@1952: }
ds@1952: 
ds@1952: #ifndef SQLITE_OMIT_TRIGGER
ds@1952: /* This function is used by SQL generated to implement the
ds@1952: ** ALTER TABLE command. The first argument is the text of a CREATE TRIGGER 
ds@1952: ** statement. The second is a table name. The table name in the CREATE 
ds@1952: ** TRIGGER statement is replaced with the third argument and the result 
ds@1952: ** returned. This is analagous to renameTableFunc() above, except for CREATE
ds@1952: ** TRIGGER, not CREATE INDEX and CREATE TABLE.
ds@1952: */
ds@1952: static void renameTriggerFunc(
ds@1952:   sqlite3_context *context,
ds@1952:   int argc,
ds@1952:   sqlite3_value **argv
ds@1952: ){
ds@1952:   unsigned char const *zSql = sqlite3_value_text(argv[0]);
ds@1952:   unsigned char const *zTableName = sqlite3_value_text(argv[1]);
ds@1952: 
ds@1952:   int token;
ds@1952:   Token tname;
ds@1952:   int dist = 3;
ds@1952:   unsigned char const *zCsr = zSql;
ds@1952:   int len = 0;
ds@1952:   char *zRet;
ds@1952: 
ds@1952:   sqlite3 *db = sqlite3_user_data(context);
ds@1952: 
ds@1952:   /* The principle used to locate the table name in the CREATE TRIGGER 
ds@1952:   ** statement is that the table name is the first token that is immediatedly
ds@1952:   ** preceded by either TK_ON or TK_DOT and immediatedly followed by one
ds@1952:   ** of TK_WHEN, TK_BEGIN or TK_FOR.
ds@1952:   */
ds@1952:   if( zSql ){
ds@1952:     do {
ds@1952: 
ds@1952:       if( !*zCsr ){
ds@1952:         /* Ran out of input before finding the table name. Return NULL. */
ds@1952:         return;
ds@1952:       }
ds@1952: 
ds@1952:       /* Store the token that zCsr points to in tname. */
ds@1952:       tname.z = zCsr;
ds@1952:       tname.n = len;
ds@1952: 
ds@1952:       /* Advance zCsr to the next token. Store that token type in 'token',
ds@1952:       ** and it's length in 'len' (to be used next iteration of this loop).
ds@1952:       */
ds@1952:       do {
ds@1952:         zCsr += len;
ds@1952:         len = sqlite3GetToken(zCsr, &token);
ds@1952:       }while( token==TK_SPACE );
ds@1952:       assert( len>0 );
ds@1952: 
ds@1952:       /* Variable 'dist' stores the number of tokens read since the most
ds@1952:       ** recent TK_DOT or TK_ON. This means that when a WHEN, FOR or BEGIN 
ds@1952:       ** token is read and 'dist' equals 2, the condition stated above
ds@1952:       ** to be met.
ds@1952:       **
ds@1952:       ** Note that ON cannot be a database, table or column name, so
ds@1952:       ** there is no need to worry about syntax like 
ds@1952:       ** "CREATE TRIGGER ... ON ON.ON BEGIN ..." etc.
ds@1952:       */
ds@1952:       dist++;
ds@1952:       if( token==TK_DOT || token==TK_ON ){
ds@1952:         dist = 0;
ds@1952:       }
ds@1952:     } while( dist!=2 || (token!=TK_WHEN && token!=TK_FOR && token!=TK_BEGIN) );
ds@1952: 
ds@1952:     /* Variable tname now contains the token that is the old table-name
ds@1952:     ** in the CREATE TRIGGER statement.
ds@1952:     */
ds@1952:     zRet = sqlite3MPrintf(db, "%.*s%Q%s", tname.z - zSql, zSql, 
ds@1952:        zTableName, tname.z+tname.n);
ds@1952:     sqlite3_result_text(context, zRet, -1, sqlite3_free);
ds@1952:   }
ds@1952: }
ds@1952: #endif   /* !SQLITE_OMIT_TRIGGER */
ds@1952: 
ds@1952: /*
ds@1952: ** Register built-in functions used to help implement ALTER TABLE
ds@1952: */
ds@1952: void sqlite3AlterFunctions(sqlite3 *db){
ds@1952:   static const struct {
ds@1952:      char *zName;
ds@1952:      signed char nArg;
ds@1952:      void (*xFunc)(sqlite3_context*,int,sqlite3_value **);
ds@1952:   } aFuncs[] = {
ds@1952:     { "sqlite_rename_table",    2, renameTableFunc},
ds@1952: #ifndef SQLITE_OMIT_TRIGGER
ds@1952:     { "sqlite_rename_trigger",  2, renameTriggerFunc},
ds@1952: #endif
ds@1952:   };
ds@1952:   int i;
ds@1952: 
ds@1952:   for(i=0; i<sizeof(aFuncs)/sizeof(aFuncs[0]); i++){
ds@1952:     sqlite3CreateFunc(db, aFuncs[i].zName, aFuncs[i].nArg,
ds@1952:         SQLITE_UTF8, (void *)db, aFuncs[i].xFunc, 0, 0);
ds@1952:   }
ds@1952: }
ds@1952: 
ds@1952: /*
ds@1952: ** Generate the text of a WHERE expression which can be used to select all
ds@1952: ** temporary triggers on table pTab from the sqlite_temp_master table. If
ds@1952: ** table pTab has no temporary triggers, or is itself stored in the 
ds@1952: ** temporary database, NULL is returned.
ds@1952: */
ds@1952: static char *whereTempTriggers(Parse *pParse, Table *pTab){
ds@1952:   Trigger *pTrig;
ds@1952:   char *zWhere = 0;
ds@1952:   char *tmp = 0;
ds@1952:   const Schema *pTempSchema = pParse->db->aDb[1].pSchema; /* Temp db schema */
ds@1952: 
ds@1952:   /* If the table is not located in the temp-db (in which case NULL is 
ds@1952:   ** returned, loop through the tables list of triggers. For each trigger
ds@1952:   ** that is not part of the temp-db schema, add a clause to the WHERE 
ds@1952:   ** expression being built up in zWhere.
ds@1952:   */
ds@1952:   if( pTab->pSchema!=pTempSchema ){
ds@1952:     sqlite3 *db = pParse->db;
ds@1952:     for( pTrig=pTab->pTrigger; pTrig; pTrig=pTrig->pNext ){
ds@1952:       if( pTrig->pSchema==pTempSchema ){
ds@1952:         if( !zWhere ){
ds@1952:           zWhere = sqlite3MPrintf(db, "name=%Q", pTrig->name);
ds@1952:         }else{
ds@1952:           tmp = zWhere;
ds@1952:           zWhere = sqlite3MPrintf(db, "%s OR name=%Q", zWhere, pTrig->name);
ds@1952:           sqlite3_free(tmp);
ds@1952:         }
ds@1952:       }
ds@1952:     }
ds@1952:   }
ds@1952:   return zWhere;
ds@1952: }
ds@1952: 
ds@1952: /*
ds@1952: ** Generate code to drop and reload the internal representation of table
ds@1952: ** pTab from the database, including triggers and temporary triggers.
ds@1952: ** Argument zName is the name of the table in the database schema at
ds@1952: ** the time the generated code is executed. This can be different from
ds@1952: ** pTab->zName if this function is being called to code part of an 
ds@1952: ** "ALTER TABLE RENAME TO" statement.
ds@1952: */
ds@1952: static void reloadTableSchema(Parse *pParse, Table *pTab, const char *zName){
ds@1952:   Vdbe *v;
ds@1952:   char *zWhere;
ds@1952:   int iDb;                   /* Index of database containing pTab */
ds@1952: #ifndef SQLITE_OMIT_TRIGGER
ds@1952:   Trigger *pTrig;
ds@1952: #endif
ds@1952: 
ds@1952:   v = sqlite3GetVdbe(pParse);
ds@1952:   if( !v ) return;
ds@1952:   assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
ds@1952:   iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
ds@1952:   assert( iDb>=0 );
ds@1952: 
ds@1952: #ifndef SQLITE_OMIT_TRIGGER
ds@1952:   /* Drop any table triggers from the internal schema. */
ds@1952:   for(pTrig=pTab->pTrigger; pTrig; pTrig=pTrig->pNext){
ds@1952:     int iTrigDb = sqlite3SchemaToIndex(pParse->db, pTrig->pSchema);
ds@1952:     assert( iTrigDb==iDb || iTrigDb==1 );
ds@1952:     sqlite3VdbeOp3(v, OP_DropTrigger, iTrigDb, 0, pTrig->name, 0);
ds@1952:   }
ds@1952: #endif
ds@1952: 
ds@1952:   /* Drop the table and index from the internal schema */
ds@1952:   sqlite3VdbeOp3(v, OP_DropTable, iDb, 0, pTab->zName, 0);
ds@1952: 
ds@1952:   /* Reload the table, index and permanent trigger schemas. */
ds@1952:   zWhere = sqlite3MPrintf(pParse->db, "tbl_name=%Q", zName);
ds@1952:   if( !zWhere ) return;
ds@1952:   sqlite3VdbeOp3(v, OP_ParseSchema, iDb, 0, zWhere, P3_DYNAMIC);
ds@1952: 
ds@1952: #ifndef SQLITE_OMIT_TRIGGER
ds@1952:   /* Now, if the table is not stored in the temp database, reload any temp 
ds@1952:   ** triggers. Don't use IN(...) in case SQLITE_OMIT_SUBQUERY is defined. 
ds@1952:   */
ds@1952:   if( (zWhere=whereTempTriggers(pParse, pTab))!=0 ){
ds@1952:     sqlite3VdbeOp3(v, OP_ParseSchema, 1, 0, zWhere, P3_DYNAMIC);
ds@1952:   }
ds@1952: #endif
ds@1952: }
ds@1952: 
ds@1952: /*
ds@1952: ** Generate code to implement the "ALTER TABLE xxx RENAME TO yyy" 
ds@1952: ** command. 
ds@1952: */
ds@1952: void sqlite3AlterRenameTable(
ds@1952:   Parse *pParse,            /* Parser context. */
ds@1952:   SrcList *pSrc,            /* The table to rename. */
ds@1952:   Token *pName              /* The new table name. */
ds@1952: ){
ds@1952:   int iDb;                  /* Database that contains the table */
ds@1952:   char *zDb;                /* Name of database iDb */
ds@1952:   Table *pTab;              /* Table being renamed */
ds@1952:   char *zName = 0;          /* NULL-terminated version of pName */ 
ds@1952:   sqlite3 *db = pParse->db; /* Database connection */
ds@1952:   int nTabName;             /* Number of UTF-8 characters in zTabName */
ds@1952:   const char *zTabName;     /* Original name of the table */
ds@1952:   Vdbe *v;
ds@1952: #ifndef SQLITE_OMIT_TRIGGER
ds@1952:   char *zWhere = 0;         /* Where clause to locate temp triggers */
ds@1952: #endif
ds@1952:   int isVirtualRename = 0;  /* True if this is a v-table with an xRename() */
ds@1952:   
ds@1952:   if( db->mallocFailed ) goto exit_rename_table;
ds@1952:   assert( pSrc->nSrc==1 );
ds@1952:   assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
ds@1952: 
ds@1952:   pTab = sqlite3LocateTable(pParse, pSrc->a[0].zName, pSrc->a[0].zDatabase);
ds@1952:   if( !pTab ) goto exit_rename_table;
ds@1952:   iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
ds@1952:   zDb = db->aDb[iDb].zName;
ds@1952: 
ds@1952:   /* Get a NULL terminated version of the new table name. */
ds@1952:   zName = sqlite3NameFromToken(db, pName);
ds@1952:   if( !zName ) goto exit_rename_table;
ds@1952: 
ds@1952:   /* Check that a table or index named 'zName' does not already exist
ds@1952:   ** in database iDb. If so, this is an error.
ds@1952:   */
ds@1952:   if( sqlite3FindTable(db, zName, zDb) || sqlite3FindIndex(db, zName, zDb) ){
ds@1952:     sqlite3ErrorMsg(pParse, 
ds@1952:         "there is already another table or index with this name: %s", zName);
ds@1952:     goto exit_rename_table;
ds@1952:   }
ds@1952: 
ds@1952:   /* Make sure it is not a system table being altered, or a reserved name
ds@1952:   ** that the table is being renamed to.
ds@1952:   */
ds@1952:   if( strlen(pTab->zName)>6 && 0==sqlite3StrNICmp(pTab->zName, "sqlite_", 7) ){
ds@1952:     sqlite3ErrorMsg(pParse, "table %s may not be altered", pTab->zName);
ds@1952:     goto exit_rename_table;
ds@1952:   }
ds@1952:   if( SQLITE_OK!=sqlite3CheckObjectName(pParse, zName) ){
ds@1952:     goto exit_rename_table;
ds@1952:   }
ds@1952: 
ds@1952: #ifndef SQLITE_OMIT_AUTHORIZATION
ds@1952:   /* Invoke the authorization callback. */
ds@1952:   if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab->zName, 0) ){
ds@1952:     goto exit_rename_table;
ds@1952:   }
ds@1952: #endif
ds@1952: 
ds@1952: #ifndef SQLITE_OMIT_VIRTUALTABLE
ds@1952:   if( sqlite3ViewGetColumnNames(pParse, pTab) ){
ds@1952:     goto exit_rename_table;
ds@1952:   }
ds@1952:   if( IsVirtual(pTab) && pTab->pMod->pModule->xRename ){
ds@1952:     isVirtualRename = 1;
ds@1952:   }
ds@1952: #endif
ds@1952: 
ds@1952:   /* Begin a transaction and code the VerifyCookie for database iDb. 
ds@1952:   ** Then modify the schema cookie (since the ALTER TABLE modifies the
ds@1952:   ** schema). Open a statement transaction if the table is a virtual
ds@1952:   ** table.
ds@1952:   */
ds@1952:   v = sqlite3GetVdbe(pParse);
ds@1952:   if( v==0 ){
ds@1952:     goto exit_rename_table;
ds@1952:   }
ds@1952:   sqlite3BeginWriteOperation(pParse, isVirtualRename, iDb);
ds@1952:   sqlite3ChangeCookie(db, v, iDb);
ds@1952: 
ds@1952:   /* If this is a virtual table, invoke the xRename() function if
ds@1952:   ** one is defined. The xRename() callback will modify the names
ds@1952:   ** of any resources used by the v-table implementation (including other
ds@1952:   ** SQLite tables) that are identified by the name of the virtual table.
ds@1952:   */
ds@1952: #ifndef SQLITE_OMIT_VIRTUALTABLE
ds@1952:   if( isVirtualRename ){
ds@1952:     sqlite3VdbeOp3(v, OP_String8, 0, 0, zName, 0);
ds@1952:     sqlite3VdbeOp3(v, OP_VRename, 0, 0, (const char*)pTab->pVtab, P3_VTAB);
ds@1952:   }
ds@1952: #endif
ds@1952: 
ds@1952:   /* figure out how many UTF-8 characters are in zName */
ds@1952:   zTabName = pTab->zName;
ds@1952:   nTabName = sqlite3Utf8CharLen(zTabName, -1);
ds@1952: 
ds@1952:   /* Modify the sqlite_master table to use the new table name. */
ds@1952:   sqlite3NestedParse(pParse,
ds@1952:       "UPDATE %Q.%s SET "
ds@1952: #ifdef SQLITE_OMIT_TRIGGER
ds@1952:           "sql = sqlite_rename_table(sql, %Q), "
ds@1952: #else
ds@1952:           "sql = CASE "
ds@1952:             "WHEN type = 'trigger' THEN sqlite_rename_trigger(sql, %Q)"
ds@1952:             "ELSE sqlite_rename_table(sql, %Q) END, "
ds@1952: #endif
ds@1952:           "tbl_name = %Q, "
ds@1952:           "name = CASE "
ds@1952:             "WHEN type='table' THEN %Q "
ds@1952:             "WHEN name LIKE 'sqlite_autoindex%%' AND type='index' THEN "
ds@1952:              "'sqlite_autoindex_' || %Q || substr(name,%d+18,10) "
ds@1952:             "ELSE name END "
ds@1952:       "WHERE tbl_name=%Q AND "
ds@1952:           "(type='table' OR type='index' OR type='trigger');", 
ds@1952:       zDb, SCHEMA_TABLE(iDb), zName, zName, zName, 
ds@1952: #ifndef SQLITE_OMIT_TRIGGER
ds@1952:       zName,
ds@1952: #endif
ds@1952:       zName, nTabName, zTabName
ds@1952:   );
ds@1952: 
ds@1952: #ifndef SQLITE_OMIT_AUTOINCREMENT
ds@1952:   /* If the sqlite_sequence table exists in this database, then update 
ds@1952:   ** it with the new table name.
ds@1952:   */
ds@1952:   if( sqlite3FindTable(db, "sqlite_sequence", zDb) ){
ds@1952:     sqlite3NestedParse(pParse,
ds@1952:         "UPDATE %Q.sqlite_sequence set name = %Q WHERE name = %Q",
ds@1952:         zDb, zName, pTab->zName);
ds@1952:   }
ds@1952: #endif
ds@1952: 
ds@1952: #ifndef SQLITE_OMIT_TRIGGER
ds@1952:   /* If there are TEMP triggers on this table, modify the sqlite_temp_master
ds@1952:   ** table. Don't do this if the table being ALTERed is itself located in
ds@1952:   ** the temp database.
ds@1952:   */
ds@1952:   if( (zWhere=whereTempTriggers(pParse, pTab))!=0 ){
ds@1952:     sqlite3NestedParse(pParse, 
ds@1952:         "UPDATE sqlite_temp_master SET "
ds@1952:             "sql = sqlite_rename_trigger(sql, %Q), "
ds@1952:             "tbl_name = %Q "
ds@1952:             "WHERE %s;", zName, zName, zWhere);
ds@1952:     sqlite3_free(zWhere);
ds@1952:   }
ds@1952: #endif
ds@1952: 
ds@1952:   /* Drop and reload the internal table schema. */
ds@1952:   reloadTableSchema(pParse, pTab, zName);
ds@1952: 
ds@1952: exit_rename_table:
ds@1952:   sqlite3SrcListDelete(pSrc);
ds@1952:   sqlite3_free(zName);
ds@1952: }
ds@1952: 
ds@1952: 
ds@1952: /*
ds@1952: ** This function is called after an "ALTER TABLE ... ADD" statement
ds@1952: ** has been parsed. Argument pColDef contains the text of the new
ds@1952: ** column definition.
ds@1952: **
ds@1952: ** The Table structure pParse->pNewTable was extended to include
ds@1952: ** the new column during parsing.
ds@1952: */
ds@1952: void sqlite3AlterFinishAddColumn(Parse *pParse, Token *pColDef){
ds@1952:   Table *pNew;              /* Copy of pParse->pNewTable */
ds@1952:   Table *pTab;              /* Table being altered */
ds@1952:   int iDb;                  /* Database number */
ds@1952:   const char *zDb;          /* Database name */
ds@1952:   const char *zTab;         /* Table name */
ds@1952:   char *zCol;               /* Null-terminated column definition */
ds@1952:   Column *pCol;             /* The new column */
ds@1952:   Expr *pDflt;              /* Default value for the new column */
ds@1952:   sqlite3 *db;              /* The database connection; */
ds@1952: 
ds@1952:   if( pParse->nErr ) return;
ds@1952:   pNew = pParse->pNewTable;
ds@1952:   assert( pNew );
ds@1952: 
ds@1952:   db = pParse->db;
ds@1952:   assert( sqlite3BtreeHoldsAllMutexes(db) );
ds@1952:   iDb = sqlite3SchemaToIndex(db, pNew->pSchema);
ds@1952:   zDb = db->aDb[iDb].zName;
ds@1952:   zTab = pNew->zName;
ds@1952:   pCol = &pNew->aCol[pNew->nCol-1];
ds@1952:   pDflt = pCol->pDflt;
ds@1952:   pTab = sqlite3FindTable(db, zTab, zDb);
ds@1952:   assert( pTab );
ds@1952: 
ds@1952: #ifndef SQLITE_OMIT_AUTHORIZATION
ds@1952:   /* Invoke the authorization callback. */
ds@1952:   if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab->zName, 0) ){
ds@1952:     return;
ds@1952:   }
ds@1952: #endif
ds@1952: 
ds@1952:   /* If the default value for the new column was specified with a 
ds@1952:   ** literal NULL, then set pDflt to 0. This simplifies checking
ds@1952:   ** for an SQL NULL default below.
ds@1952:   */
ds@1952:   if( pDflt && pDflt->op==TK_NULL ){
ds@1952:     pDflt = 0;
ds@1952:   }
ds@1952: 
ds@1952:   /* Check that the new column is not specified as PRIMARY KEY or UNIQUE.
ds@1952:   ** If there is a NOT NULL constraint, then the default value for the
ds@1952:   ** column must not be NULL.
ds@1952:   */
ds@1952:   if( pCol->isPrimKey ){
ds@1952:     sqlite3ErrorMsg(pParse, "Cannot add a PRIMARY KEY column");
ds@1952:     return;
ds@1952:   }
ds@1952:   if( pNew->pIndex ){
ds@1952:     sqlite3ErrorMsg(pParse, "Cannot add a UNIQUE column");
ds@1952:     return;
ds@1952:   }
ds@1952:   if( pCol->notNull && !pDflt ){
ds@1952:     sqlite3ErrorMsg(pParse, 
ds@1952:         "Cannot add a NOT NULL column with default value NULL");
ds@1952:     return;
ds@1952:   }
ds@1952: 
ds@1952:   /* Ensure the default expression is something that sqlite3ValueFromExpr()
ds@1952:   ** can handle (i.e. not CURRENT_TIME etc.)
ds@1952:   */
ds@1952:   if( pDflt ){
ds@1952:     sqlite3_value *pVal;
ds@1952:     if( sqlite3ValueFromExpr(db, pDflt, SQLITE_UTF8, SQLITE_AFF_NONE, &pVal) ){
ds@1952:       db->mallocFailed = 1;
ds@1952:       return;
ds@1952:     }
ds@1952:     if( !pVal ){
ds@1952:       sqlite3ErrorMsg(pParse, "Cannot add a column with non-constant default");
ds@1952:       return;
ds@1952:     }
ds@1952:     sqlite3ValueFree(pVal);
ds@1952:   }
ds@1952: 
ds@1952:   /* Modify the CREATE TABLE statement. */
ds@1952:   zCol = sqlite3DbStrNDup(db, (char*)pColDef->z, pColDef->n);
ds@1952:   if( zCol ){
ds@1952:     char *zEnd = &zCol[pColDef->n-1];
ds@1952:     while( (zEnd>zCol && *zEnd==';') || isspace(*(unsigned char *)zEnd) ){
ds@1952:       *zEnd-- = '\0';
ds@1952:     }
ds@1952:     sqlite3NestedParse(pParse, 
ds@1952:         "UPDATE %Q.%s SET "
ds@1952:           "sql = substr(sql,1,%d) || ', ' || %Q || substr(sql,%d,length(sql)) "
ds@1952:         "WHERE type = 'table' AND name = %Q", 
ds@1952:       zDb, SCHEMA_TABLE(iDb), pNew->addColOffset, zCol, pNew->addColOffset+1,
ds@1952:       zTab
ds@1952:     );
ds@1952:     sqlite3_free(zCol);
ds@1952:   }
ds@1952: 
ds@1952:   /* If the default value of the new column is NULL, then set the file
ds@1952:   ** format to 2. If the default value of the new column is not NULL,
ds@1952:   ** the file format becomes 3.
ds@1952:   */
ds@1952:   sqlite3MinimumFileFormat(pParse, iDb, pDflt ? 3 : 2);
ds@1952: 
ds@1952:   /* Reload the schema of the modified table. */
ds@1952:   reloadTableSchema(pParse, pTab, pTab->zName);
ds@1952: }
ds@1952: 
ds@1952: /*
ds@1952: ** This function is called by the parser after the table-name in
ds@1952: ** an "ALTER TABLE <table-name> ADD" statement is parsed. Argument 
ds@1952: ** pSrc is the full-name of the table being altered.
ds@1952: **
ds@1952: ** This routine makes a (partial) copy of the Table structure
ds@1952: ** for the table being altered and sets Parse.pNewTable to point
ds@1952: ** to it. Routines called by the parser as the column definition
ds@1952: ** is parsed (i.e. sqlite3AddColumn()) add the new Column data to 
ds@1952: ** the copy. The copy of the Table structure is deleted by tokenize.c 
ds@1952: ** after parsing is finished.
ds@1952: **
ds@1952: ** Routine sqlite3AlterFinishAddColumn() will be called to complete
ds@1952: ** coding the "ALTER TABLE ... ADD" statement.
ds@1952: */
ds@1952: void sqlite3AlterBeginAddColumn(Parse *pParse, SrcList *pSrc){
ds@1952:   Table *pNew;
ds@1952:   Table *pTab;
ds@1952:   Vdbe *v;
ds@1952:   int iDb;
ds@1952:   int i;
ds@1952:   int nAlloc;
ds@1952:   sqlite3 *db = pParse->db;
ds@1952: 
ds@1952:   /* Look up the table being altered. */
ds@1952:   assert( pParse->pNewTable==0 );
ds@1952:   assert( sqlite3BtreeHoldsAllMutexes(db) );
ds@1952:   if( db->mallocFailed ) goto exit_begin_add_column;
ds@1952:   pTab = sqlite3LocateTable(pParse, pSrc->a[0].zName, pSrc->a[0].zDatabase);
ds@1952:   if( !pTab ) goto exit_begin_add_column;
ds@1952: 
ds@1952: #ifndef SQLITE_OMIT_VIRTUALTABLE
ds@1952:   if( IsVirtual(pTab) ){
ds@1952:     sqlite3ErrorMsg(pParse, "virtual tables may not be altered");
ds@1952:     goto exit_begin_add_column;
ds@1952:   }
ds@1952: #endif
ds@1952: 
ds@1952:   /* Make sure this is not an attempt to ALTER a view. */
ds@1952:   if( pTab->pSelect ){
ds@1952:     sqlite3ErrorMsg(pParse, "Cannot add a column to a view");
ds@1952:     goto exit_begin_add_column;
ds@1952:   }
ds@1952: 
ds@1952:   assert( pTab->addColOffset>0 );
ds@1952:   iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
ds@1952: 
ds@1952:   /* Put a copy of the Table struct in Parse.pNewTable for the
ds@1952:   ** sqlite3AddColumn() function and friends to modify.
ds@1952:   */
ds@1952:   pNew = (Table*)sqlite3DbMallocZero(db, sizeof(Table));
ds@1952:   if( !pNew ) goto exit_begin_add_column;
ds@1952:   pParse->pNewTable = pNew;
ds@1952:   pNew->nRef = 1;
ds@1952:   pNew->nCol = pTab->nCol;
ds@1952:   assert( pNew->nCol>0 );
ds@1952:   nAlloc = (((pNew->nCol-1)/8)*8)+8;
ds@1952:   assert( nAlloc>=pNew->nCol && nAlloc%8==0 && nAlloc-pNew->nCol<8 );
ds@1952:   pNew->aCol = (Column*)sqlite3DbMallocZero(db, sizeof(Column)*nAlloc);
ds@1952:   pNew->zName = sqlite3DbStrDup(db, pTab->zName);
ds@1952:   if( !pNew->aCol || !pNew->zName ){
ds@1952:     db->mallocFailed = 1;
ds@1952:     goto exit_begin_add_column;
ds@1952:   }
ds@1952:   memcpy(pNew->aCol, pTab->aCol, sizeof(Column)*pNew->nCol);
ds@1952:   for(i=0; i<pNew->nCol; i++){
ds@1952:     Column *pCol = &pNew->aCol[i];
ds@1952:     pCol->zName = sqlite3DbStrDup(db, pCol->zName);
ds@1952:     pCol->zColl = 0;
ds@1952:     pCol->zType = 0;
ds@1952:     pCol->pDflt = 0;
ds@1952:   }
ds@1952:   pNew->pSchema = db->aDb[iDb].pSchema;
ds@1952:   pNew->addColOffset = pTab->addColOffset;
ds@1952:   pNew->nRef = 1;
ds@1952: 
ds@1952:   /* Begin a transaction and increment the schema cookie.  */
ds@1952:   sqlite3BeginWriteOperation(pParse, 0, iDb);
ds@1952:   v = sqlite3GetVdbe(pParse);
ds@1952:   if( !v ) goto exit_begin_add_column;
ds@1952:   sqlite3ChangeCookie(db, v, iDb);
ds@1952: 
ds@1952: exit_begin_add_column:
ds@1952:   sqlite3SrcListDelete(pSrc);
ds@1952:   return;
ds@1952: }
ds@1952: #endif  /* SQLITE_ALTER_TABLE */