SQL 面试题与答案
Test your skills through the online practice test: SQL Quiz Online Practice Test
问题 6. What is a event handler ?
An event handler is a routine that is written to respond to a particular event.
这有帮助吗？
添加评论
查看评论
问题 7. What is an integrity constraint ?
An integrity constraint allows the definition of certain restrictions, at the table level, on the data that is entered into a table.
这有帮助吗？
添加评论
查看评论
问题 8. What are the various uses of database triggers ?
Database triggers can be used to enforce business rules, to maintain derived values and perform value-based auditing.
这有帮助吗？
添加评论
查看评论
问题 9. What is a transaction ?
A transaction is a set of operations that begin when the first DML is issued and end when a commit or rollback is issued. BEGIN COMMIT/ROLLBACK are the boundries of a transaction.
这有帮助吗？
添加评论
查看评论
问题 10. Why are the integrity constraints preferred to database triggers ?
Because it is easier to define an integrity constraint than a database trigger.
这有帮助吗？
添加评论
查看评论
用户评价最有帮助的内容：