带有SQL Server的Java持久性-无法插入行，但与mysql兼容，为什么？ 投诉该表已存在

Question

Here is my code:

package sqlserver;

import it.bsec.target.entity.Colore;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

public class Test1 {

    public static void main(String[] args) {
        try {
            Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
        } catch (ClassNotFoundException e1) {
            System.out.println("Failed to register the driver.");
        }

        String connectionUrl = "jdbc:sqlserver://localhost:3306;" +
                   "databaseName=target;integratedSecurity=true;encrypt=true;trustServerCertificate=true;";
        try {
            Connection con = DriverManager.getConnection(connectionUrl);
            Statement stmt = con.createStatement();
            String s = "use target";
            String sql = "SELECT * FROM dbo.Colori";
            ResultSet rs = stmt.executeQuery(sql);
            while(rs.next()) {
                int id  = rs.getInt("Id");
                String desc = rs.getString("Descrizione");
                System.out.println(id + " : " + desc);
            }

            System.setProperty("eclipselink.target-database", "SqlServer");
            System.setProperty("javax.persistence.jdbc.driver", "com.microsoft.sqlserver.jdbc.SQLServerDriver");
            System.setProperty("javax.persistence.jdbc.url", System.getProperty("jdbc.url", "jdbc:sqlserver://localhost:3306;databaseName=target;integratedSecurity=true;encrypt=true;trustServerCertificate=true;"));
            EntityManagerFactory factory = Persistence.createEntityManagerFactory("TARGET", System.getProperties());
            EntityManager entityManager = factory.createEntityManager();

            Colore c = new Colore();
            c.setId(6);
            c.setDescrizione("WHITE");
            entityManager.persist(c);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

This query results in insertion of a new row into a table Colori in MySQL. When I run this example from within Eclipse with SQL Server, this is what I get (and insertion fails):

1 : BLUE
2 : GREY
3 : GREEN
4 : RED
5 : YELLOW
[EL Warning]: Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.1.2.v20101206-r8635): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: com.microsoft.sqlserver.jdbc.SQLServerException: There is already an object named 'Colori' in the database.
Error Code: 2714
Call: CREATE TABLE dbo.Colori (Id INTEGER NOT NULL, Descrizione VARCHAR(255) NULL, PRIMARY KEY (Id))
Query: DataModifyQuery(sql="CREATE TABLE dbo.Colori (Id INTEGER NOT NULL, Descrizione VARCHAR(255) NULL, PRIMARY KEY (Id))")

But it is enough to modify this code slightly like so:

package sqlserver;

import it.bsec.target.entity.Colore;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

public class Test1 {

    public static void main(String[] args) {
        try {
            Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
        } catch (ClassNotFoundException e1) {
            System.out.println("Failed to register the driver.");
        }

        String connectionUrl = "jdbc:sqlserver://localhost:3306;" +
                   "databaseName=target;integratedSecurity=true;encrypt=true;trustServerCertificate=true;";
        try {
            Connection con = DriverManager.getConnection(connectionUrl);
            Statement stmt = con.createStatement();
            String s = "use target";
            String sql = "SELECT * FROM dbo.Colori";
            ResultSet rs = stmt.executeQuery(sql);
            while(rs.next()) {
                int id  = rs.getInt("Id");
                String desc = rs.getString("Descrizione");
                System.out.println(id + " : " + desc);
            }

            System.setProperty("eclipselink.target-database", "SqlServer");
            System.setProperty("javax.persistence.jdbc.driver", "com.microsoft.sqlserver.jdbc.SQLServerDriver");
            System.setProperty("javax.persistence.jdbc.url", System.getProperty("jdbc.url", "jdbc:sqlserver://localhost:3306;databaseName=target;integratedSecurity=true;encrypt=true;trustServerCertificate=true;"));
            EntityManagerFactory factory = Persistence.createEntityManagerFactory("TARGET", System.getProperties());
            EntityManager entityManager = factory.createEntityManager();
            entityManager.getTransaction().begin();
            entityManager.createNativeQuery("insert into dbo.Colori(Id, Descrizione) values ('6', 'WHITE')").executeUpdate();
            entityManager.getTransaction().commit();
            entityManager.persist(c);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

And this is an error I still get:

1 : BLUE
2 : GREY
3 : GREEN
4 : RED
5 : YELLOW
[EL Warning]: Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.1.2.v20101206-r8635): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: com.microsoft.sqlserver.jdbc.SQLServerException: There is already an object named 'Colori' in the database.
Error Code: 2714
Call: CREATE TABLE dbo.Colori (Id INTEGER NOT NULL, Descrizione VARCHAR(255) NULL, PRIMARY KEY (Id))
Query: DataModifyQuery(sql="CREATE TABLE dbo.Colori (Id INTEGER NOT NULL, Descrizione VARCHAR(255) NULL, PRIMARY KEY (Id))")

HOWEVER, THIS TIME INSERTION SUCCEEDS (despite an error)! Does anyone understand why is it so and what am I doing wrong? In particular, why do I get error saying basically that table exists?? Of course it exists, it supposed to, no? How else could I try to insert anything into non existent table? How this can be an error?

I am using slqjdbc4 driver, eclipse link, java 6 EE persistence framework and below, I include code of my Entity Bean:

package it.bsec.target.entity;

import java.io.Serializable;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name="dbo.Colori")
@SuppressWarnings("serial")
public class Colore implements Serializable {

    @Id
    @Column(name = "Id")
    private Integer id;

    @Column(name = "Descrizione", length = 255)
    private String descrizione;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getDescrizione() {
        return descrizione;
    }

    public void setDescrizione(String descrizione) {
        this.descrizione = descrizione;
    }

}

Is just SQLServer not compatible with java persistence framework? I know it sounds strange, but what else can be the reason? Sorry, but I clearly don't know what is going wrong. Needless to say, the above query works perfectly when executed from within SQL Server Management Studio.

---

EDIT: As suggested by Jens, I have added property eclipselink.ddl-generation and set its value to update, easy fix - now it does work with native queries, however when try an example with where I am trying persist an Entity Bean, it still fails (No error this time!) but it doesn't add any new row into the table. Any one knows what am I still missing and where would be a good source of information for this type of things, that I could learn from? Thanks.

Answer 1

It will be done by JPA. try to add the property eclipselink.ddl-generation and set the value to update

      System.setProperty("eclipselink.ddl-generation", "update");