In this example we are using the DatabaseMetaData to retrieve table’s column names. The metadata information can be obtained by calling the connection.getMetaData()
. Next, we can then get a ResultSet
object by calling metadata.getColumns(String catalog, String schemaPattern, String tableNamePattern, String columnNamePattern)
.
From this result set COLUMN_NAME
, TYPE_NAME
, COLUMN_SIZE
and others information can be read.
package org.kodejava.example.jdbc;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
public class DbMetadataExample {
private static final String URL = "jdbc:mysql://localhost/kodejava";
private static final String USERNAME = "root";
private static final String PASSWORD = "";
public static void main(String[] args) {
try (Connection connection =
DriverManager.getConnection(URL, USERNAME, PASSWORD)) {
DatabaseMetaData metadata = connection.getMetaData();
ResultSet resultSet =
metadata.getColumns(null, null, "books", null);
while (resultSet.next()) {
String name = resultSet.getString("COLUMN_NAME");
String type = resultSet.getString("TYPE_NAME");
int size = resultSet.getInt("COLUMN_SIZE");
System.out.println("Column name: [" + name + "]; " +
"type: [" + type + "]; size: [" + size + "]");
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
A bit information of books
table described below:
Column name: [isbn]; type: [VARCHAR]; size: [50]
Column name: [title]; type: [VARCHAR]; size: [100]
Column name: [published_year]; type: [INT]; size: [10]
Column name: [price]; type: [DECIMAL]; size: [10]
Maven dependencies
<!-- https://search.maven.org/remotecontent?filepath=mysql/mysql-connector-java/8.0.17/mysql-connector-java-8.0.17.jar -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.17</version>
</dependency>