Import SQLite 3.7.6.3.

third_party/sqlite/src/src/alter.c

 /*
 ** 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 1.62 2009/07/24 17:58:53 danielk1977 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
 
 
@@ skipping 52 matching lines @@
       } 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,
@@ skipping 60 matching lines @@
     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(sqlite3 *db){
-  sqlite3CreateFunc(db, "sqlite_rename_table", 2, SQLITE_UTF8, 0,
-                         renameTableFunc, 0, 0);
+void sqlite3AlterFunctions(void){
+  static SQLITE_WSD FuncDef aAlterTableFuncs[] = {
+    FUNCTION(sqlite_rename_table,   2, 0, 0, renameTableFunc),
 #ifndef SQLITE_OMIT_TRIGGER
-  sqlite3CreateFunc(db, "sqlite_rename_trigger", 2, SQLITE_UTF8, 0,
-                         renameTriggerFunc, 0, 0);
+    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;
-  char *tmp = 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 ){
-        if( !zWhere ){
-          zWhere = sqlite3MPrintf(db, "name=%Q", pTrig->zName);
-        }else{
-          tmp = zWhere;
-          zWhere = sqlite3MPrintf(db, "%s OR name=%Q", zWhere, pTrig->zName);
-          sqlite3DbFree(db, tmp);
-        }
+        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.
@@ skipping 14 matching lines @@
 
 #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 */
+  /* 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
 }
 
 /*
+** 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( sqlite3Strlen30(zName)>6 && 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() */
-  
+  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);
+  if( SQLITE_OK!=isSystemTable(pParse, pTab->zName) ){
     goto exit_rename_table;
   }
-  if( SQLITE_OK!=sqlite3CheckObjectName(pParse, 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
@@ skipping 38 matching lines @@
     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
@@ skipping 31 matching lines @@
   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);
@@ skipping 68 matching lines @@
   ** 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);
@@ skipping 35 matching lines @@
     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->nRef = 1;
-  pNew->dbMem = pTab->dbMem;
   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;
   }
@@ skipping 14 matching lines @@
   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 */