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How to get the size of a column of a table using JDBC?
You can get the size of a column of a table using the getPrecision() method of the ResultSetMetaData class.
//Retrieving the ResultSetMetaData object ResultSetMetaData rsmd = rs.getMetaData(); //getting the column type int size_name = rsmd. getPrecision(3);
Assume we have a table named employee_data in the database with description as shown below:
+----------+--------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +----------+--------------+------+-----+---------+-------+ | id | int(11) | YES | | NULL | | | Name | varchar(255) | YES | | NULL | | | Dob | date | YES | | NULL | | | Location | varchar(255) | YES | | NULL | | +----------+--------------+------+-----+---------+-------+
Following JDBC program establishes connection with the database, retrieves the ResultSetMetaData object of the employee_data table, and prints the size of the third column.
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.Statement;
public class SizeOfColumn {
public static void main(String args[])throws Exception {
//Registering the Driver
DriverManager.registerDriver(new com.mysql.jdbc.Driver());
//Getting the connection
String mysqlUrl = "jdbc:mysql://localhost/mydatabase";
Connection con = DriverManager.getConnection(mysqlUrl, "root", "password");
System.out.println("Connection established......");
//Creating a Statement object
Statement stmt = con.createStatement();
ResultSet rs = stmt.executeQuery("select * from employee_data");
//Retrieving the ResultSetMetaData object
ResultSetMetaData rsmd = rs.getMetaData();
//getting the column type
int column_size = rsmd.getPrecision(3);
System.out.println("Size of the 3rd column : "+column_size);
}
}Output
Connection established...... Size of the 3rd column : 11
Updated on: 30-Jul-2019
1K+ Views
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