java 如何通过jdbc获取主键的列名
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How to get the column name of the primary key through jdbc
提问by Foredoomed
I have the code as follows:
我的代码如下：
DatabaseMetaData dmd = connection.getMetaData();
ResultSet rs = dmd.getPrimaryKeys(null, null, tableName);
while(rs.next()){
primaryKey = rs.getString("COLUMN_NAME");
}
rs is not null while rs.next()always return false, anyone has idea about it? Thanks.
rs 不是 null 而rs.next()总是 return false，有人知道吗？谢谢。
采纳答案by defender
metadata interface implementation was implemented by driver vendors. It may not be supported by some driver and some db. Here is text from javadoc: Some DatabaseMetaData methods return lists of information in the form of ResultSet objects. Regular ResultSet methods, such as getString and getInt, can be used to retrieve the data from these ResultSet objects. If a given form of metadata is not available, an empty ResultSet will be returned.
table name is case sensitive in oracle
or try the below approach
DatabaseMetaData dm = conn.getMetaData( ); ResultSet rs = dm.getExportedKeys( "" , "" , "table1" ); while( rs.next( ) ) { String pkey = rs.getString("PKCOLUMN_NAME"); System.out.println("primary key = " + pkey); }you can also use getCrossReference or getImportedKeys to retrieve primary key
元数据接口实现由驱动程序供应商实现。某些驱动程序和某些数据库可能不支持它。这是来自 javadoc 的文本：一些 DatabaseMetaData 方法以 ResultSet 对象的形式返回信息列表。常规 ResultSet 方法（例如 getString 和 getInt）可用于从这些 ResultSet 对象中检索数据。如果给定形式的元数据不可用，则将返回一个空的 ResultSet。
oracle中的表名区分大小写
或尝试以下方法
DatabaseMetaData dm = conn.getMetaData( ); ResultSet rs = dm.getExportedKeys( "" , "" , "table1" ); while( rs.next( ) ) { String pkey = rs.getString("PKCOLUMN_NAME"); System.out.println("primary key = " + pkey); }您还可以使用 getCrossReference 或 getImportedKeys 来检索主键
