jdbc获取元数据类型问题

[kaiwa8]

jdbc获取表元数据，为什么varchar会被识别成char，长度也不对。char字符长度不对，largeint识别不出来

jdbc查询结果

String sql = "select * from test_db";
Statement statement = connection.createStatement();
//执行sql语句
ResultSet rs = statement.executeQuery(sql);
//获取ResultSetMetaData对象
ResultSetMetaData metaData = rs.getMetaData();
//获取查询字段数量
int columnCount = metaData.getColumnCount();
for (int i = 1; i <= columnCount; i++) {
//获取表名称
String columnName = metaData.getColumnName(i);
//获取sql类型
String columnTypeName = metaData.getColumnTypeName(i);
int precision = metaData.getPrecision(i);
System.out.println("columnName:"+columnName+" columnTypeName: "+columnTypeName+" : "+"precision:"+precision);
}

输出

columnName:id columnTypeName: INT : precision:10
columnName:varchar2 columnTypeName: CHAR : precision:85
columnName:char2 columnTypeName: CHAR : precision:85
columnName:largeint2 columnTypeName: CHAR : precision:85

为什么varchar2字段类型是 CHAR ，precision是85？
为什么char2 precision是85？
为什么largeint2 识别出错？

[yagagagaga]

What is the version of your MySQL JDBC driver? You should try to use updated drivers as much as possible.

[kaiwa8]

8.0.28

[yagagagaga]

因为mysql没有largeint类型，所以Doris返回char类型代替，char和varchar在doris里都认为是string类型，其返回码是254，这在mysql jdbc driver里对应的是char，因此，你看到返回值是char。至于 precision ，仅有 decimal 类型会返回正确的值。

[kaiwa8]

好的，谢谢

[LuckyCaptain-go]

有什么兼容计划，或者解决办法吗？

[LemonLiTree]

https://doris.apache.org/docs/dev/admin-manual/http-actions/fe/meta-action/
It is recommended to use doris' API to obtain metadata

[kaiwa8]

好的，谢谢