表检查约束(table check constraint)对将要添加到表中的数据实施已定义的限制。例如,一个表检查约束可确保每当在 EMPLOYEE 表中添加或更新电话分机时,雇员的电话分...
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SYSCAT.COLCHECKS Contains a row for each column that is referenced by a table check constraint db2 select constname, tabname, colname, usage from syscat.colchecks
COLCHECKS 为表检查约束所引用的每个列保持一个行 db2 select constname, tabname, colname, usage from syscat.colchecks
For table, use the CHECK constraint to ensure integrity.
对于表,可以使用CHECK约束来确保完整性。
The CHECK constraint is perfect for this, as the following table definition shows.
CHECK 约束非常适合执行此项操作,如以下所示表定义。
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