Where can I find detail information about constraint ? - Mailing list pgsql-general

From 纪晓曦
Subject Where can I find detail information about constraint ?
Date
Msg-id 37a11ce00909230323p76cca9c6icbac6e6549b4950f@mail.gmail.com
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Responses Re: Where can I find detail information about constraint ?
Re: Where can I find detail information about constraint ?
List pgsql-general
I want detail usage introduction about constraint,such as how to constrain a string to be exactly 4 character and start with 'z'.
Where can I find the reference of CHECK? detail usage.

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