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我正在 PL/SQL 中创建一个表,但我希望我的char列只允许为ror d。我一直在环顾四周,但没有在网上找到具体的答案。也许我只是没有使用正确的搜索词。
char
r
d
ALTER TABLE tablename ADD CONSTRAINT constraintname CHECK (columnname IN ('r', 'd'));
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