In SQL, theALTER TABLEcommand is used to modify the structure of an existing table like adding, deleting, renaming columns, etc. Example -- add phone column to Customers tableALTERTABLECustomersADDphonevarchar(10); Run Code Here, the SQL command adds a column namedphoneto theCustomerstable. A...
For example, to reclaim the space occupied by a deleted column, the fastest method is to use the command. ALTER TABLE table ALTER COLUMN anycol TYPE anytype; In this command, anycol indicates any column existing in the table and anytype indicates the type of the prototype of the column...
Example ALTERTABLECustomers DROPCOLUMNEmail; ALTER TABLE - RENAME COLUMN To rename a column in a table, use the following syntax: ALTERTABLEtable_name RENAMECOLUMNold_nametonew_name; To rename a column in a table in SQL Server, use the following syntax: ...
CREATE TABLE dbo.doc_exc (column_a INT NOT NULL CONSTRAINT my_constraint UNIQUE) ; GO -- Example 1. Remove a single constraint. ALTER TABLE dbo.doc_exc DROP my_constraint ; GO DROP TABLE dbo.doc_exc; GO CREATE TABLE dbo.doc_exc ( column_a INT NOT NULL CONSTRAINT my_constraint UNIQUE...
For example, if DB_BLOCK_SIZE=4096, it is illegal to specify the parameter DB_4K_CACHE_SIZE (because the size for the 4 KB block cache is already specified by DB_CACHE_SIZE). DB_BLOCK_BUFFERS Parameter type Integer Default value Derived: 48 MB / DB_BLOCK_SIZE Parameter class...
默认值为OFF“超大规模”Azure SQL 数据库除外。 对于“超大规模”中的所有索引生成作,除非使用可恢复索引生成,否则始终 SORT_IN_TEMPDBON。 对于可恢复索引生成,SORT_IN_TEMPDB 始终OFF。 上 用于生成索引的中间排序结果存储在其中 tempdb。 这可以减少创建索引所需的时间。 但是,这会增加索引生成期间所使用的磁盘...
The AUTO_CLOSE setting can be a useful feature in some rare situations, for example, in a SQL Server instance without enough memory to operate stably with a large number of databases, or for a legacy 32-bit SQL Server instance with a large number of databases. In such scenarios, it might...
其中包括使用者定義類型變數或函數及使用者定義函數,但無法參考 Transact-SQL 陳述式。 partition_number必須存在,否則陳述式將會失敗。 WITH ( <single_partition_rebuild_index_option> ) SORT_IN_TEMPDB、MAXDOP、DATA_COMPRESSION和XML_COMPRESSION 是使用 (PARTITION = partition_number) 語法重建單一分割區時可以...
For example, the following statements are not allowed: ALTER TABLE t1 DROP COLUMN f1 DROP (f2); ALTER TABLE t1 DROP COLUMN f1 SET UNUSED (f2); ALTER TABLE t1 DROP (f1) ADD (f2 NUMBER); ALTER TABLE t1 SET UNUSED (f3) ADD (CONSTRAINT ck1 CHECK (f2 > 0)); You can drop an ...
Specifies the options that will be used to create the procedure. For example, to create a debuggable procedure, the following statement could be included: SET OPTION DBGVIEW = *SOURCE For more information, seeSET OPTION. The options CNULRQD, COMPILEOPT, NAMING, and SQLCA are not allowed in ...