C# Parse.ChangeCookie方法代码示例

        public static void BeginAddColumn(Parse parse, SrcList src)
        {
            Context ctx = parse.Ctx;

            // Look up the table being altered.
            Debug.Assert(parse.NewTable == null);
            Debug.Assert(Btree.HoldsAllMutexes(ctx));
            //if (ctx.MallocFailed) goto exit_begin_add_column;
            Table table = parse.LocateTableItem(false, src.Ids[0]);
            if (table == null) goto exit_begin_add_column;

#if !OMIT_VIRTUALTABLE
            if (IsVirtual(table))
            {
                parse.ErrorMsg("virtual tables may not be altered");
                goto exit_begin_add_column;
            }
#endif

            // Make sure this is not an attempt to ALTER a view.
            if (table.Select != null)
            {
                parse.ErrorMsg("Cannot add a column to a view");
                goto exit_begin_add_column;
            }
            if (IsSystemTable(parse, table.Name))
                goto exit_begin_add_column;

            Debug.Assert(table.AddColOffset > 0);
            int db = Prepare.SchemaToIndex(ctx, table.Schema);

            // 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.
            Table newTable = new Table();
            if (newTable == null) goto exit_begin_add_column;
            parse.NewTable = newTable;
            newTable.Refs = 1;
            newTable.Cols.length = table.Cols.length;
            Debug.Assert(newTable.Cols.length > 0);
            int allocs = (((newTable.Cols.length - 1) / 8) * 8) + 8;
            Debug.Assert(allocs >= newTable.Cols.length && allocs % 8 == 0 && allocs - newTable.Cols.length < 8);
            newTable.Cols.data = new Column[allocs];
            newTable.Name = C._mtagprintf(ctx, "sqlite_altertab_%s", table.Name);
            if (newTable.Cols.data == null || newTable.Name == null)
            {
                ctx.MallocFailed = true;
                goto exit_begin_add_column;
            }
            for (int i = 0; i < newTable.Cols.length; i++)
            {
                Column col = table.Cols[i].memcpy();
                col.Coll = null;
                col.Type = null;
                col.Dflt = null;
                col.Dflt = null;
                newTable.Cols[i] = col;
            }
            newTable.Schema = ctx.DBs[db].Schema;
            newTable.AddColOffset = table.AddColOffset;
            newTable.Refs = 1;

            // Begin a transaction and increment the schema cookie.
            parse.BeginWriteOperation(0, db);
            Vdbe v = parse.V;
            if (v == null) goto exit_begin_add_column;
            parse.ChangeCookie(db);

        exit_begin_add_column:
            sqlite3SrcListDelete(ctx, ref src);
            return;
        }

        public static void RenameTable(Parse parse, SrcList src, Token name)
        {
            Context ctx = parse.Ctx; // Database connection

            Context.FLAG savedDbFlags = ctx.Flags; // Saved value of db->flags
            //if (C._NEVER(ctx.MallocFailed)) goto exit_rename_table;
            Debug.Assert(src.Srcs == 1);
            Debug.Assert(Btree.HoldsAllMutexes(ctx));

            Table table = parse.LocateTableItem(false, src.Ids[0]); // Table being renamed
            if (table == null) goto exit_rename_table;
            int db = Prepare.SchemaToIndex(ctx, table.Schema); // Database that contains the table
            string dbName = ctx.DBs[db].Name; // Name of database iDb
            ctx.Flags |= Context.FLAG.PreferBuiltin;

            // Get a NULL terminated version of the new table name.
            string nameAsString = Parse.NameFromToken(ctx, name); // NULL-terminated version of pName
            if (nameAsString == null) 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 (Parse.FindTable(ctx, nameAsString, dbName) != null || Parse.FindIndex(ctx, nameAsString, dbName) != null)
            {
                parse.ErrorMsg("there is already another table or index with this name: %s", nameAsString);
                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 (IsSystemTable(parse, table.Name) || parse->CheckObjectName(nameAsString) != RC.OK)
                goto exit_rename_table;

#if !OMIT_VIEW
            if (table.Select != null)
            {
                parse.ErrorMsg("view %s may not be altered", table.Name);
                goto exit_rename_table;
            }
#endif

#if !OMIT_AUTHORIZATION
            // Invoke the authorization callback.
            if (Auth.Check(parse, AUTH.ALTER_TABLE, dbName, table.Name, null))
                goto exit_rename_table;
#endif

            VTable vtable = null; // Non-zero if this is a v-tab with an xRename()
#if !OMIT_VIRTUALTABLE
            if (parse->ViewGetColumnNames(table) != 0)
                goto exit_rename_table;
            if (E.IsVirtual(table))
            {
                vtable = VTable.GetVTable(ctx, table);
                if (vtable.IVTable.IModule.Rename == null)
                    vtable = null;
            }
#endif

            // Begin a transaction and code the VerifyCookie 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.
            Vdbe v = parse.GetVdbe();
            if (v == null) goto exit_rename_table;
            parse.BeginWriteOperation((vtable != null ? 1 : 0), db);
            parse.ChangeCookie(db);

            // 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.
#if  !OMIT_VIRTUALTABLE
            if (vtable != null)
            {
                int i = ++parse.Mems;
                v.AddOp4(OP.String8, 0, i, 0, nameAsString, 0);
                v.AddOp4(OP.VRename, i, 0, 0, vtable, Vdbe.P4T.VTAB);
                parse.MayAbort();
            }
#endif

            // figure out how many UTF-8 characters are in zName
            string tableName = table.Name; // Original name of the table
            int tableNameLength = C._utf8charlength(tableName, -1); // Number of UTF-8 characters in zTabName

#if !OMIT_TRIGGER
            string where_ = string.Empty; // Where clause to locate temp triggers
#endif

#if !OMIT_FOREIGN_KEY && !OMIT_TRIGGER
            if ((ctx.Flags & Context.FLAG.ForeignKeys) != 0)
            {
                // 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 ((where_ = WhereForeignKeys(parse, table)) != null)
                {
                    parse.NestedParse(
                        "UPDATE \"%w\".%s SET " +
                            "sql = sqlite_rename_parent(sql, %Q, %Q) " +
                            "WHERE %s;", dbName, E.SCHEMA_TABLE(db), tableName, nameAsString, where_);
                    C._tagfree(ctx, ref where_);
                }
            }
#endif

            // Modify the sqlite_master table to use the new table name.
//.........这里部分代码省略.........