mysql - 我可以使用 Hibenrate hbm2ddl 在同一个数据库中创建 MyISAM 和 InnoDB 表吗

Question

我的数据库中同时需要 MyISAM 表和 InnoDB 表，我正在使用 hbm2ddl 来创建它们。我可以使用 Hibenrate hbm2ddl 在同一个数据库中创建 MyISAM 和 InnoDB 表吗？似乎选择方言迫使我使用其中一种。

Answer 1

好吧，正如您所写，如果您使用 MySQL5InnoDBDialect，Hibernate 将生成 InnoDB 表:

public class MySQL5InnoDBDialect extends MySQL5Dialect {

    public boolean supportsCascadeDelete() {
        return true;
    }

    public String getTableTypeString() {
        return " ENGINE=InnoDB";
    }

    public boolean hasSelfReferentialForeignKeyBug() {
        return true;
    }

}

使用此方言将导致 Hibernate 在 CREATE TABLE 语句的末尾添加 ENGINE=InnoDB。但这是全局设置，您不能在实体级别调整此行为。

要使用 hbm2ddl 并混合两个表引擎，我的建议是事后更改特定表。为此，您可以使用 5.7. Auxiliary database objects .来自文档:

5.7. Auxiliary database objects

Auxiliary database objects allow for the CREATE and DROP of arbitrary database objects. In conjunction with Hibernate's schema evolution tools, they have the ability to fully define a user schema within the Hibernate mapping files. Although designed specifically for creating and dropping things like triggers or stored procedures, any SQL command that can be run via a java.sql.Statement.execute() method is valid (for example, ALTERs, INSERTS, etc.). There are essentially two modes for defining auxiliary database objects:

The first mode is to explicitly list the CREATE and DROP commands in the mapping file:

<hibernate-mapping>
    ...
    <database-object>
        <create>CREATE TRIGGER my_trigger ...</create>
        <drop>DROP TRIGGER my_trigger</drop>
    </database-object>
</hibernate-mapping>

The second mode is to supply a custom class that constructs the CREATE and DROP commands. This custom class must implement the org.hibernate.mapping.AuxiliaryDatabaseObject interface.

<hibernate-mapping>
    ...
    <database-object>
        <definition class="MyTriggerDefinition"/>
    </database-object>
</hibernate-mapping>

Additionally, these database objects can be optionally scoped so that they only apply when certain dialects are used.

<hibernate-mapping>
    ...
    <database-object>
        <definition class="MyTriggerDefinition"/>
        <dialect-scope name="org.hibernate.dialect.Oracle9iDialect"/>
        <dialect-scope name="org.hibernate.dialect.Oracle10gDialect"/>
    </database-object>
</hibernate-mapping>

另一种选择是(ab)使用 Hibernate import.sql feature执行 ALTER。