dbAnt

今天探索一下唯一性约束和唯一索引的关系，我们先抛出问题，这两者的效果是否一致的呢？ 官方文档的解释： Unique Constraints A unique key constraint requires that every value in a column or set of columns be unique. No rows of a table may have duplicate values in a column (theunique key) or set of columns (the composite unique key) with a unique key constraint. Note: The term key refers only to the columns defined in the integrity constraint. Because the database enforces a unique constraint by ...... >>阅读全文<<