Use Varchar Type As Column Type : Column « JPA

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Java Tutorial » JPA » Column

22.21.8.Use Varchar Type As Column TypePrevious/Next

File: Employee.java

import javax.persistence.Column;

import javax.persistence.Entity;

import javax.persistence.Id;

import javax.persistence.JoinColumn;

import javax.persistence.ManyToOne;



@Entity

public class Employee {

    @Id

    @Column(columnDefinition="VARCHAR(40)") 

    private String name;







    public String getName() {

        return name;

    }

    

    public void setName(String name) {

        this.name = name;

    }





}

File: Helper.java

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.ResultSet;

import java.sql.ResultSetMetaData;

import java.sql.Statement;



public class Helper {

  public static void checkData() throws Exception {

    Class.forName("org.hsqldb.jdbcDriver");

    Connection conn = DriverManager.getConnection("jdbc:hsqldb:data/tutorial", "sa", "");

    Statement st = conn.createStatement();



    ResultSet mrs = conn.getMetaData().getTables(null, null, null, new String[] { "TABLE" });

    while (mrs.next()) {

      String tableName = mrs.getString(3);

      System.out.println("\n\n\n\nTable Name: "+ tableName);



      ResultSet rs = st.executeQuery("select * from " + tableName);

      ResultSetMetaData metadata = rs.getMetaData();

      while (rs.next()) {

        System.out.println(" Row:");

        for (int i = 0; i < metadata.getColumnCount(); i++) {

          System.out.println("    Column Name: "+ metadata.getColumnLabel(i + 1)+ ",  ");

          System.out.println("    Column Type: "+ metadata.getColumnTypeName(i + 1)+ ":  ");

          Object value = rs.getObject(i + 1);

          System.out.println("    Column Value: "+value+"\n");

        }

      }

    }

  }

}

File: Main.java

import java.util.List;



import javax.persistence.EntityManager;

import javax.persistence.EntityManagerFactory;

import javax.persistence.Persistence;

import javax.persistence.Query;



public class Main {

  static EntityManagerFactory emf = Persistence.createEntityManagerFactory("JPAService");



  static EntityManager em = emf.createEntityManager();



  public static void main(String[] a) throws Exception {

    em.getTransaction().begin();









    em.getTransaction().commit();

    em.close();

    emf.close();



    Helper.checkData();

  }

}

File: persistence.xml

<persistence xmlns="http://java.sun.com/xml/ns/persistence"

             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

             xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence" version="1.0">

  <persistence-unit name="JPAService" transaction-type="RESOURCE_LOCAL">

    <properties>

      <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/>

      <property name="hibernate.hbm2ddl.auto" value="update"/>

      <property name="hibernate.connection.driver_class" value="org.hsqldb.jdbcDriver"/>

      <property name="hibernate.connection.username" value="sa"/>

      <property name="hibernate.connection.password" value=""/>

      <property name="hibernate.connection.url" value="jdbc:hsqldb:data/tutorial"/>

    </properties>

  </persistence-unit>

</persistence>

Download: JPA-EefineVarcharTypeAsColumnType.zip( 5,287 k)

22.21.Column
	22.21.1.	Unique, Not Nullable Column
	22.21.2.	Specify Column Definition To Field
	22.21.3.	Set Precision And Scale
	22.21.4.	Set Column Length
	22.21.5.	Java String Mapped To Varchar
	22.21.6.	Java Long Mapped To Big Int
	22.21.7.	Java Int Mapped To Integer
	22.21.8.	Use Varchar Type As Column Type
	22.21.9.	Compound Primary key
	22.21.10.	Change Default Column Name

Use Varchar Type As Column Type : Column « JPA « Java Tutorial