so that the information can be retrieved quickly. Indexes can be created on a single column or a group of columns. When a index is created, it first sorts the data and then it assigns a ROWID for each row.
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Indexes and constraints SQL Server automatically creates indexes when PRIMARY KEY and UNIQUE constraints are defined on table columns. For example, when you create a table with a UNIQUE constraint, Database Engine automatically creates a nonclustered index. If you configure a ...
This article describes how to disable an index or constraints in SQL Server by using SQL Server Management Studio or Transact-SQL. Disabling an index prevents user access to the index, and for clustered indexes to the underlying table data. The index definition remains in metadata, and index st...
FROM USER_IND_COLUMNS T, USER_INDEXES I WHERE T.INDEX_NAME = I.INDEX_NAME AND T.TABLE_NAME = I.TABLE_NAME AND T.TABLE_NAME = 表名 1. 2. 3. 4. 5. 约束 视图说明 user_constraints是表约束的视图,描述的是约束类型(constraint_type)是什么,属于哪些表(table_name),如果约束的类型为R(外键...
This topic describes how to disable an index or constraints in SQL Server by using SQL Server Management Studio or Transact-SQL. Disabling an index prevents user access to the index, and for clustered indexes to the underlying table data. The index definition remains in metadata, and index ...
This article describes how to disable an index or constraints in SQL Server by using SQL Server Management Studio or Transact-SQL. Disabling an index prevents user access to the index, and for clustered indexes to the underlying table data. The index definition remains in metadata, and index ...
For more information, see Disable indexes and constraints and Enable indexes and constraints. REORGANIZE a rowstore index For rowstore indexes, REORGANIZE specifies to reorganize the index leaf level. The REORGANIZE operation is: Always performed online. This means long-term blocking table locks aren'...
创建一个新的聚集索引将启用以前禁用的非聚集索引。 有关详细信息,请参阅Enable Indexes and Constraints。 如果表是一个堆,将重新生成所有非聚集索引。 权限 若要执行ALTER INDEX,至少需要对表或视图具有ALTER权限。 使用SQL Server Management Studio 禁用索引 ...
For more information, see Disable indexes and constraints and Enable indexes and constraints. REORGANIZE a rowstore index For rowstore indexes, REORGANIZE specifies to reorganize the index leaf level. The REORGANIZE operation is: Always performed online. This means long-term blocking table locks aren'...