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                合規國際互聯網加速 OSASE為企業客戶提供高速穩定SD-WAN國際加速解決方案。 廣告
                表約束 === ## db.sql ~~~ CREATE TABLE posts ( id SERIAL PRIMARY KEY, title VARCHAR(255) NOT NULL, context TEXT CHECK( LENGTH(context) > 3), is_draft BOOLEAN DEFAULT TRUE, is_del BOOLEAN DEFAULT FALSE , created_date TIMESTAMP DEFAULT 'now' ); ~~~ ## 約束條件 ``` not null : 不能為空 unique :在所有u數據中值必須唯一 check :字段設置條件 default :字段默認值 primart key(not null , unique): 主鍵,不能為空,且不能重復 ```
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