If a schema-bound view or function references the column. For more information, see COLLATE. NULL | NOT NULL Specifies whether the column can accept null values. Columns that don't allow null values are added with ALTER TABLE only if they have a default specified or if the table is empty...
稀疏列已针对 NULL 值进行了存储优化。 不能将稀疏列指定为 NOT NULL。 有关稀疏列的其他限制和详细信息,请参阅使用稀疏列。MASKED WITH ( FUNCTION = 'mask_function' )适用于:SQL Server 2016 (13.x) 及更高版本。指定动态数据掩码。 mask_function 是具有相应参数的掩码函数的名称。 有四个函数可供选择...
列の削除や、一部のエディションの SQL Server における既定値を伴う NOT NULL 列の追加など、大規模なテーブル内のすべての行に影響する変更は、その実行終了までに長い時間がかかり、多くのログ レコードが生成されます。 これらの ALTER TABLE ステートメントは、多くの行に影響する INSERT...
The decision whether to use a few or many keys isn't easy. The appropriate keys and the number of active keys to use is a compromise between maximizing the speed of data retrieval and data updates (operations that insert, delete, or modify data). In general, it may be worthwhile to dea...
CTAS does not support theOPENJSONfunction as part of theSELECTstatement. As an alternative, useINSERT INTO ... SELECT. For example: SQL DECLARE@jsonNVARCHAR(MAX) = N' [ { "id": 1, "name": "Alice", "age": 30, "address": { "street": "123 Main St", "city": "Wonderland" } ...
expr: This is an expression that returns JSON data. This can be a constant ('{"a":1}'), a column (t1.json_data, given tablet1specified prior toJSON_TABLE()in theFROMclause), or a function call (JSON_EXTRACT(t1.json_data,'$.post.comments')). ...
Tables are created with no data unless a subquery is specified. You can add rows to a table with theINSERTstatement. After creating a table, you can define additional columns, partitions, and integrity constraints with theADDclause of theALTERTABLEstatement. You can change the definition of an...
The table must be a typed table (the OF clause must be present) that is not a subtable (SQLSTATE 42613). The name for the column is defined as OID-column-name and cannot be the same as the name of any attribute of the structured type type-name1 (SQLSTATE 42711). The column is ...
Otherwise, a new function is created. function-name Names the user-defined function. The combination of name, schema name, the number of parameters, and the data type of each parameter (without regard for any length, precision, scale, or CCSID attributes of the data type) must not identify...
[params]) -->Cursor||Create a new Cursor object, call its execute method, andreturnit. See|Cursor.executeformore details.||This is a convenience method that is not part of the DB API. Since a new|Cursor is allocated by each call, this should not be usedifmore than one SQL|statement...