CREATE table Student( s_id int NOT NULL CHECK(s_id > 0), Name varchar(60) NOT NULL, Age int ); The above query will restrict thes_idvalue to be greater than zero. UsingCHECKconstraint at Column Level ALTER table Student ADD CHECK(s_id > 0); ...
SQL 型 V4.2.3 参考指南 系统视图 Oracle 租户系统视图 字典视图 ALL_CONSTRAINTS 更新时间:2024-11-20 16:06:11 编辑 功能描述 查看用户可访问的所有表的约束信息。 功能适用性 该视图仅适用于 OceanBase 数据库 Oracle 模式。 字段说明 字段名称类型是否可以为 NULL描述 ...
Theuser_constraintsare utilized to display the names of the constraints in the database. Theall_constraintsprovides the metadata about all constraints that are accessible to the current user, regardless of the schema. Commonly Used Constraints in Oracle SQL Most commonly used constraints in Oracle SQ...
以下SQL语句可以查询特定表的所有唯一性约束的详细信息: SELECT CONSTRAINT_NAME, COLUMN_NAME FROM all_cons_columns WHERE TABLE_NAME = 'EMPLOYEES' AND CONSTRAINT_NAME IN ( SELECT CONSTRAINT_NAME FROM all_constraints WHERE TABLE_NAME = 'EMPLOYEES' AND CONSTRAINT_TYPE = 'U'); 该语句将返回所有属于EMP...
https://www.runoob.com/sql/sql-wildcards.html SQL 快速参考 https://www.runoob.com/sql/sql-quickref.html SQL 视图(Views) https://www.runoob.com/sql/sql-view.html SQL 约束(Constraints) https://www.runoob.com/sql/sql-constraints.html ...
See Also:constraintsinOracle Database SQL Language Reference LAST_CHANGE DATE When the constraint was last enabled or disabled INDEX_OWNER VARCHAR2(128) Name of the user owning the index INDEX_NAME VARCHAR2(128) Name of the index (only shown for unique and primary-key constraints) ...
The EAV model does not come without drawbacks: It is almost impossible to use constraints for data validation, for example. However, the most puzzling issue with the EAV model is that the transformation into a one-column-per-attribute notation is almost always done using joins—quite often one...
有关列级 CHECK 约束,请参阅sys.check_constraints (Transact-SQL)。 is_sparsebit1 = 列为稀疏列。 有关详细信息,请参阅使用稀疏列。 is_column_setbit1 = 列为列集。 有关详细信息,请参阅使用列集。 generated_always_typetinyint适用于:SQL Server 2016 (13.x) 及更高版本、...
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