public interface DbMapper {/*** 查询数据库类型*/String queryDbType();
}<select id="queryDbType" resultType="java.lang.String">select<choose><when test="_databaseId == 'mysql'">'mysql'</when><when test="_databaseId == 'oracle'">'oracle'</when><when test="_databaseId == 'sqlserver'">'sqlserver'</when><when test="_databaseId == 'db2'">'db2'</when><when test="_databaseId == 'postgresql'">'postgresql'</when><when test="_databaseId == 'dm'">'dm'</when><otherwise>'unknown'</otherwise></choose> as dbType</select>
