选择了DEFERRABLE选项
可以通过SET CONSTRAINTS 语句控制约束检查
文档上面的例子:
Setting Constraints Examples
The following statement sets all deferrable constraints in this transaction to be checked immediately following each DML statement:
SET CONSTRAINTS ALL IMMEDIATE;
The following statement checks three deferred constraints when the transaction is committed:
SET CONSTRAINTS unq_name, scott.nn_sal,
adams.pk_dept@dblink DEFERRED;