Query and creation of Oracle primary key, Federated primary key

--Query whether a table has a unique primary key

Select cu.* from User_cons_columns cu, user_constraints au where cu.constraint_name = Au.constraint_name and Au.constraint _type = ' P ' and au.table_name = ' table name '

--Query whether a table has a federated primary key

Select cu.* from User_cons_columns cu, user_constraints au where cu.constraint_name = Au.constraint_name and Au.constraint _type = ' U ' and au.table_name = ' table name '

--Create unique primary key

ALTER TABLE name add constraint pk_table primary key (ID); --pk_table refers to the name of the primary key, and the ID in parentheses refers to the unique primary key of the table.

--Create a federated primary key

ALTER TABLE name add constraint ak_table unique (name,age,sex); --ak_table refers to the name of the Federated primary Key, and the name,age,sex in parentheses refers to the Union primary key of the table.

Query and creation of Oracle primary key, Federated primary key