Mysql中文版手册中翻译不太严谨

godknow

线上查看的中文版本：

15.2.6.4.外键约束
....

外键定义服从下列情况：

·         所有tables必须是InnoDB型，它们不能是临时表。

·         在引用表中，必须有一个索引，外键列以同样的顺序被列在其中作为第一列。这样一个索引如果不存在，它必须在引用表里被自动创建。

·         在引用表中，必须有一个索引，被引用的列以同样的顺序被列在其中作为第一列。

·         不支持对外键列的索引前缀。这样的后果之一是BLOB和TEXT列不被包括在一个外键中，这是因为对这些列的索引必须总是包含一个前缀长度。

·         如果CONSTRAINTsymbol被给出，它在数据库里必须是唯一的。如果它没有被给出，InnoDB自动创建这个名字。

英文版本：

Foreign keys definitions are subject to the following conditions:
Both tables must be InnoDB tables and they must not be TEMPORARY tables.

·         Corresponding columns in the foreign key and the referenced key must have similar internal data types inside InnoDB so that they can be compared without a type conversion. The size and sign of integer types must be the same. The length of string types need not be the same. For non-binary (character) string columns, the character set and collation must be the same.

·         In the referencing table, there must be an index where the foreign key columns are listed as the first columns in the same order. Such an index is created on the referencing table automatically if it does not exist. index_name, if given, is used as described previously.

·         In the referenced table, there must be an index where the referenced columns are listed as the first columns in the same order.

·         Index prefixes on foreign key columns are not supported. One consequence of this is that BLOB and TEXT columns cannot be included in a foreign key, because indexes on those columns must always include a prefix length.

·         If the CONSTRAINT symbol clause is given, the symbol value must be unique in the database. If the clause is not given, InnoDB creates the name automatically.


referencing table 和referenced table 都翻译成为“引用表”太不严谨了。