java.sql Interface ResultSetMetaData

最新推荐文章于 2024-04-28 23:26:31 发布

转载最新推荐文章于 2024-04-28 23:26:31 发布 · 322 阅读

本文介绍ResultSetMetaData接口，它是获取ResultSet对象中列类型和属性信息的工具。文章通过示例展示了如何使用此接口来确定列的数量及是否可以在WHERE子句中使用第一列。

All Superinterfaces:

Wrapper

All Known Subinterfaces:

RowSetMetaData

All Known Implementing Classes:

RowSetMetaDataImpl

public interface ResultSetMetaData
extends Wrapper

An object that can be used to get information about the types and properties of the columns in a ResultSet object. The following code fragment creates the ResultSet object rs, creates the ResultSetMetaData object rsmd, and uses rsmd to find out how many columns rs has and whether the first column in rs can be used in a WHERE clause.

     ResultSet rs = stmt.executeQuery("SELECT a, b, c FROM TABLE2");
     ResultSetMetaData rsmd = rs.getMetaData();
     int numberOfColumns = rsmd.getColumnCount();
     boolean b = rsmd.isSearchable(1);

isSearchable

boolean isSearchable(int column)

throws SQLException

Indicates whether the designated column can be used in a where clause.

Parameters:

column - the first column is 1, the second is 2, ...

Returns:

true if so; false otherwise

Throws:

SQLException - if a database access error occurs