how to get what are the unique columns from given table in java jdbc driver-CodePudding

let say i have table called "person" and it has 4 columns(name,last_name,city,pincode) out of them 2 columns (name,last_name) are unique columns . And i want to get these 2 columns information from java jdbc driver. and my question is how get this information from java jdbc driver

CodePudding user response：

Here you have a simple example based on MySql:

public class Test {
static final String DB_URL = "jdbc:mysql://localhost:3306/yourDatabase";
static final String USER = "----";
static final String PASS = "somePass";
static final String QUERY = "SHOW KEYS FROM YOUR_TABLE WHERE Key_name = 'PRIMARY'\n";

public static void main(String[] args) {
    // Open a connection
    final ArrayList<String> primaryKeyColumns = new ArrayList<>();
    try(Connection conn = DriverManager.getConnection(DB_URL, USER, PASS);
        Statement stmt = conn.createStatement();
        ResultSet rs = stmt.executeQuery(QUERY);) {
        while (rs.next()) {
            primaryKeyColumns.add(rs.getString(5));
        }
    } catch (SQLException e) {
        e.printStackTrace();
    }
    System.out.println(primaryKeyColumns);
}

}

Look at the used query in this way you can fetch more specific information.

CodePudding user response：

This document describes the ResultSet and lays out that you can obtain a ResultSetMetaData object. But documentation of ResultSetMetaData shows that there is no way to retriev information about column constraints.