SELECTconstraint_name,constraint_type,search_condition FROMuser_constraints WHEREtable_name='EMPLOYEES'; 约束类型 C--CHECK和NOT NULL都算为C TYPE P--PRIMARY KEY R--REFERENTIAL INTEGRITY就是外部键约束 U--UNIQUE SELECTconstraint_name,column_name FROMuser_cons_columns WHEREtable_name='EMPLOYEES';
The childandparent tables must beonthe samedatabase.Toenable referential integrity constraints across nodesofadistributeddatabase, you mustusedatabasetriggers. SeeCREATETRIGGER. 字表和父表必须在同一个数据库。分布式数据库中,外键不能跨节点,但触发器可以Ifeither the childorparent objectisaview,thenthecons...
的plsql工具并不提供对notnull的约束名称只是在非空上打挑而已定义约束名称的时候不太注意constraintname的规范这样不好当现场环境比较恶劣光秃秃没有plsql工具只有sqlplus可供使用的时候我在丹东港做生产的时候就是我们需要明确区别各属性约束情况的时候只按照系统自动提供的以sys编号的约束名是很费力气的影响操作效率 ...
注: 最后那里的 WHERE 填写的条件的注意：C (check constraint on a table) C 表示 CHECK 约束。P (primary key) P 表示主键U (unique key) U 表示唯一R (referential integrity) P 表示引用(外键)V (with check option, on a view)O (with read only, on a view)知道表名...
CCheck constraint on a table PPrimary key UUnique key RReferential integrity VWith check option, on a view OWith read only, on a view HHash expression FConstraint that involves a REF column SSupplemental logging 对于H、S类型,尚不清楚情况,而且从上面我在11g数据库实验结果看,也没发现这两种类型...
Type of Constraint Definition: C:(check constraint on a table) | P:(primary key) | U:(unique key) | R:(referential integrity) V:(with check option, on a view) | O:(with read only, on a view). SQL> SELECT ucc.column_name,ucc.constraint_name,uc.constraint_type,uc.status ...
By requiring that the value for a foreign key exist in another table, the foreign key constraint enforces referential integrity in the database. Foreign keys not only provide a way to join related tables but also ensure that the relationship between the two tables will have the required data ...
ORACLE数据库系统是美国ORACLE公司(甲骨文)提供的以分布式数据库为核心的一组软件产品,是目前最流行的客户/服务器(CLIENT/SERVER)或B/S体系结构的数据库之一。在真正使用Oracle数据库之前,我们应该提前了解Oracle数据库特点,便于我们的使用。 1、完整的数据管理功能: ...
How to check the Referential integrity constraints in the table SQL> select CONSTRAINT_NAME C_NAME,INDEX_NAME,CONSTRAINT_TYPE,Search_condition,R_CONSTRAINT_NAME R_NAME from user_constraints where TABLE_NAME='EMP' and CONSTRAINT_TYPE='R' ; ...
C Check constraint on a table P Primary key U Unique key R Referential integrity V With check option, on a view O With read only, on a view H Hash expression F Constraint that involves a REF column S Supplemental logging 对于H、S类型,尚不清楚情况,而且从上面我在11g数据库实验结果看,也没...