> For the complete documentation index, see [llms.txt](https://docs.postgresql.tw/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.postgresql.tw/client-interfaces/information-schema/infoschema-check-constraints.md).

# 35.9. check\_constraints \#

檢視表 `check_constraints` 包含目前已啟用角色所擁有、定義於資料表或 domain 上的所有檢查約束。（資料表或 domain 的擁有者即為約束的擁有者。）

SQL 標準將非空值約束視為具有 `CHECK (column_name IS NOT NULL)` 表示式的檢查約束。因此非空值約束也包含在此處，沒有專屬的檢視表。

**表 35.7. `check_constraints` 欄位**

| <p>欄位類型</p><p>說明</p>                                                                            |
| ----------------------------------------------------------------------------------------------- |
| <p><code>constraint\_catalog</code> <code>sql\_identifier</code></p><p>包含約束的資料庫名稱（一律為目前資料庫）</p> |
| <p><code>constraint\_schema</code> <code>sql\_identifier</code></p><p>包含約束的 schema 名稱</p>       |
| <p><code>constraint\_name</code> <code>sql\_identifier</code></p><p>約束名稱</p>                    |
| <p><code>check\_clause</code> <code>character\_data</code></p><p>檢查約束的檢查表示式</p>                 |

<br>

***

【[PostgreSQL 18.6 文件](https://www.postgresql.org/docs/18/infoschema-check-constraints.html)】


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