C# Parse.NestedParse方法代码示例

        static void OpenStatTable(Parse parse, int db, int statCur, string where_, string whereType)
        {
            int[] roots = new int[] { 0, 0 };
            byte[] createTbls = new byte[] { 0, 0 };

            Context ctx = parse.Ctx;
            Vdbe v = parse.GetVdbe();
            if (v == null) return;
            Debug.Assert(Btree.HoldsAllMutexes(ctx));
            Debug.Assert(v.Ctx == ctx);
            Context.DB dbObj = ctx.DBs[db];

            for (int i = 0; i < _tables.Length; i++)
            {
                string tableName = _tables[i].Name;
                Table stat;
                if ((stat = Parse.FindTable(ctx, tableName, dbObj.Name)) == null)
                {
                    // The sqlite_stat[12] table does not exist. Create it. Note that a side-effect of the CREATE TABLE statement is to leave the rootpage 
                    // of the new table in register pParse.regRoot. This is important because the OpenWrite opcode below will be needing it.
                    parse.NestedParse("CREATE TABLE %Q.%s(%s)", dbObj.Name, tableName, _tables[i].Cols);
                    roots[i] = parse.RegRoot;
                    createTbls[i] = Vdbe::OPFLAG_P2ISREG;
                }
                else
                {
                    // The table already exists. If zWhere is not NULL, delete all entries associated with the table zWhere. If zWhere is NULL, delete the
                    // entire contents of the table.
                    roots[i] = stat.Id;
                    sqlite3TableLock(parse, db, roots[i], 1, tableName);
                    if (where_ == null)
                        parse.NestedParse("DELETE FROM %Q.%s WHERE %s=%Q", dbObj.Name, tableName, whereType, where_);
                    else
                        v.AddOp2(OP.Clear, roots[i], db); // The sqlite_stat[12] table already exists.  Delete all rows.
                }
            }

            // Open the sqlite_stat[12] tables for writing.
            for (int i = 0; i < _tables.Length; i++)
            {
                v.AddOp3(OP.OpenWrite, statCur + i, roots[i], db);
                v.ChangeP4(-1, 3, Vdbe.P4T.INT32);
                v.ChangeP5(createTbls[i]);
            }
        }

        public static void FinishAddColumn(Parse parse, Token colDef)
        {
            Context ctx = parse.Ctx; // The database connection
            if (parse.Errs != 0 || ctx.MallocFailed) return;
            Table newTable = parse.NewTable; // Copy of pParse.pNewTable
            Debug.Assert(newTable != null);
            Debug.Assert(Btree.HoldsAllMutexes(ctx));
            int db = Prepare.SchemaToIndex(ctx, newTable.Schema); // Database number
            string dbName = ctx.DBs[db].Name;// Database name
            string tableName = newTable.Name.Substring(16); // Table name: Skip the "sqlite_altertab_" prefix on the name
            Column col = newTable.Cols[newTable.Cols.length - 1]; // The new column
            Expr dflt = col.Dflt; // Default value for the new column
            Table table = Parse.FindTable(ctx, tableName, dbName); // Table being altered
            Debug.Assert(table != null);

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

            // 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 (dflt != null && dflt.OP == TK.NULL)
                dflt = null;

            // 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 ((col.ColFlags & COLFLAG.PRIMKEY) != 0)
            {
                parse.ErrorMsg("Cannot add a PRIMARY KEY column");
                return;
            }
            if (newTable.Index != null)
            {
                parse.ErrorMsg("Cannot add a UNIQUE column");
                return;
            }
            if ((ctx.Flags & Context.FLAG.ForeignKeys) != 0 && newTable.FKeys != null && dflt != null)
            {
                parse.ErrorMsg("Cannot add a REFERENCES column with non-NULL default value");
                return;
            }
            if (col.NotNull != 0 && dflt == null)
            {
                parse.ErrorMsg("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 (dflt != null)
            {
                Mem val = null;
                if (Mem_FromExpr(ctx, dflt, TEXTENCODE.UTF8, AFF.NONE, ref val) != 0)
                {
                    ctx.MallocFailed = true;
                    return;
                }
                if (val == null)
                {
                    parse.ErrorMsg("Cannot add a column with non-constant default");
                    return;
                }
                Mem_Free(ref val);
            }

            // Modify the CREATE TABLE statement.
            string colDefAsString = colDef.data.Substring(0, (int)colDef.length).Replace(";", " ").Trim(); // Null-terminated column definition
            if (colDefAsString != null)
            {
                Context.FLAG savedDbFlags = ctx.Flags;
                ctx.Flags |= Context.FLAG.PreferBuiltin;
                parse.NestedParse(
                "UPDATE \"%w\".%s SET " +
                "sql = substr(sql,1,%d) || ', ' || %Q || substr(sql,%d) " +
                "WHERE type = 'table' AND name = %Q",
                dbName, E.SCHEMA_TABLE(db), newTable.AddColOffset, colDefAsString, newTable.AddColOffset + 1,
                tableName);
                C._tagfree(ctx, ref colDefAsString);
                ctx.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.
            MinimumFileFormat(parse, db, (dflt != null ? 3 : 2));

            // Reload the schema of the modified table.
            ReloadTableSchema(parse, table, table.Name);
        }

        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.........