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Java ResultSetMetaData Interface
- java.sql.ResultSetMetaData is also one of the frequently used interface in the JDBC API.
- This interface provides quick overview about a ResultSet object like number of columns, column name, data type of a column etc.
- You often need this info about a ResultSet object before processing the actual data of a ResultSet.
ResultSetMetaData In JDBC
- ResultSetMetaData is an interface in java.sql package of JDBC API which is used to get the metadata about a ResultSet object.
- Whenever you query the database using SELECT statement, the result will be stored in a ResultSet object.
- Every ResultSet object is associated with one ResultSetMetaData object.
- This object will have all the meta data about a ResultSet object like schema name, table name, number of columns, column name, datatype of a column etc.
- You can get this ResultSetMetaData object using getMetaData() method of ResultSet.
Methods of ResultSetMetaData interface
| Method | Description |
|---|---|
| public int getColumnCount()throws SQLException | Returns the total number of columns in ResultSet object. |
| public String getColumnName(int index)throws SQLException | Returns the column name of specified column index. |
| public String getColumnTypeName(int index)throws SQLException | Returns the column type name for the specified index. |
| public String getTableName(int index)throws SQLException | Returns the table name for the specified column index. |
How to get the object of ResultSetMetaData ?
- The getMetaData() method of ResultSet interface returns the object of ResultSetMetaData.
Syntax
public ResultSetMetaData getMetaData()throws SQLException click below button to copy the code. By - java tutorial - team
Sample Code
Create Table “wikitechy_employee” :
CREATE TABLE "wikitechy_employee"
( "ID" NUMBER NOT NULL ENABLE,
"FIRST_NAME" VARCHAR2(200),
"LAST_NAME" VARCHAR2(200),
"DISIGNATION" VARCHAR2(200)
);click below button to copy the code. By - java tutorial - team
Java Program
import java.sql.*;
public class ResultSetMetaDataExample
{
static
{
//Registering The Driver Class
try
{
Class.forName("oracle.jdbc.driver.OracleDriver");
}
catch (ClassNotFoundException e)
{
System.out.println("Unable To Load The Driver class");
}
}
public static void main(String[] args)
{
Connection con = null;
Statement stmt = null;
ResultSet rs = null;
try
{
//Database Credentials
String URL = "jdbc:oracle:thin:@localhost:1521:XE";
String username = "username";
String password = "password";
//Creating The Connection Object
con = DriverManager.getConnection(URL, username, password);
//Creating The Statement Object
stmt = con.createStatement();
//Constructing The SQL Query
String sql = "SELECT * FROM wikitechy_employee";
//Executing The Query
rs = stmt.executeQuery(sql);
//getting ResultSetMetaData object
ResultSetMetaData wiki = rs.getMetaData();
//getting number of columns in 'rs'
int colCount = wiki.getColumnCount();
System.out.println("Number Of Columns : "+colCount);
System.out.println("column Details :");
for (int i = 1; i <= colCount; i++)
{
//getting column name of index 'i'
String colName = wiki.getColumnName(i);
//getting column's data type of index 'i'
String colType = wiki.getColumnTypeName(i);
System.out.println(colName+" is of type "+colType);
}
}
catch (SQLException e)
{
e.printStackTrace();
}
finally
{
//Closing The DB Resources
//Closing the ResultSet object
try
{
if(rs!=null)
{
rs.close();
rs=null;
}
}
catch (SQLException e)
{
e.printStackTrace();
}
//Closing the Statement object
try
{
if(stmt!=null)
{
stmt.close();
stmt=null;
}
}
catch (SQLException e)
{
e.printStackTrace();
}
//Closing the Connection object
try
{
if(con!=null)
{
con.close();
con=null;
}
}
catch (SQLException e)
{
e.printStackTrace();
}
}
}
}click below button to copy the code. By - java tutorial - team
Output
Number Of Columns : 4
column Details :
ID is of type NUMBER
FIRST_NAME is of type VARCHAR2
LAST_NAME is of type VARCHAR2
DISIGNATION is of type VARCHAR2