Question

如何判断HSQLDB中定义了哪些外键？

我从文档中得到的最好的是：

select * from INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS;

但这只给了我以下内容。

CONSTRAINT_CATALOG CONSTRAINT_SCHEMA CONSTRAINT_NAME UNIQUE_CONSTRAINT_CATALOG UNIQUE_CONSTRAINT_SCHEMA UNIQUE_CONSTRAINT_NAME MATCH_OPTION UPDATE_RULE DELETE_RULE 
------------------ ----------------- --------------- ------------------------- ------------------------ ---------------------- ------------ ----------- ----------- 
PUBLIC             PUBLIC            SYS_FK_10078    PUBLIC                    PUBLIC                   SYS_PK_10029           NONE         NO ACTION   CASCADE     
PUBLIC             PUBLIC            SYS_FK_10079    PUBLIC                    PUBLIC                   SYS_PK_10029           NONE         NO ACTION   NO ACTION   
PUBLIC             PUBLIC            SYS_FK_10080    PUBLIC                    PUBLIC                   SYS_PK_10071           NONE         NO ACTION   CASCADE     
PUBLIC             PUBLIC            SYS_FK_10116    PUBLIC                    PUBLIC                   SYS_PK_10071           NONE         NO ACTION   CASCADE     
PUBLIC             PUBLIC            SYS_FK_10120    PUBLIC                    PUBLIC                   SYS_PK_10029           NONE         NO ACTION   CASCADE     
PUBLIC             PUBLIC            SYS_FK_10124    PUBLIC                    PUBLIC                   SYS_PK_10029           NONE         NO ACTION   NO ACTION   
PUBLIC             PUBLIC            SYS_FK_10128    PUBLIC                    PUBLIC                   SYS_PK_10071           NONE         NO ACTION   CASCADE     
PUBLIC             PUBLIC            SYS_FK_10131    PUBLIC                    PUBLIC                   SYS_PK_10071           NONE         NO ACTION   CASCADE

我需要知道哪些表和列分配了外键，我需要能够删除它们。

Answer 1

您可以将以下选项与REFERENTIAL_CONSTRAINTS视图结合使用：

select * from information_schema.constraint_column_usage
select * from information_schema.constraint_table_usage

或者，INFORMATION_SCHEMA.SYSTEM_CROSSREFERENCE视图是外键，其表和列的自包含视图。

请参阅http://hsqldb.org/doc/2.0/guide/databaseobjects-chapt.html#dbc_information_schema以获取列表。

如何确定HSQLDB中定义的外键？

1 个答案: