Why my order of execute is wrong?

Please, help me, i already week cannot find cause.
If hibernate.hbm2ddl.auto set-up “create-drop” i will be have a trouble:

dependences
<dependency>
        <groupId>org.hibernate.javax.persistence</groupId>
        <artifactId>hibernate-jpa-2.1-api</artifactId>
        <version>1.0.2.Final</version>
</dependency>
<dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-core</artifactId>
        <version>5.3.7.Final</version>
</dependency>
<dependency>
        <groupId>org.hibernate.common</groupId>
        <artifactId>hibernate-commons-annotations</artifactId>
        <version>5.0.5.Final</version>
</dependency>
cfg.xml
<?xml version = "1.0" encoding = "utf-8"?>
<!DOCTYPE hibernate-configuration SYSTEM
        "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>

        <property name = "hibernate.dialect">
            org.hibernate.dialect.MySQL57Dialect
        </property>

        <property name = "hibernate.connection.driver_class">
            com.mysql.cj.jdbc.Driver
        </property>

        <property name = "hibernate.connection.url">
            jdbc:mysql://192.168.1.29:3306/tdb?autoReconnect=true&amp;useSSL=false
        </property>

        <property name = "hibernate.connection.username">
            rt
        </property>

        <property name = "hibernate.connection.password">
            y4OjNKOI9xnMXuV20uG
        </property>

        <property name = "hibernate.temp.use_jdbc_metadata_defaults">
            false
        </property>
        <property name = "hibernate.hbm2ddl.auto">
            create-drop
        </property>
        <property name = "show_sql">
            true
        </property>
        <property name = "hibernate.id.new_generator_mappings">
            false
        </property>
        <property name = "hibernate.globally_quoted_identifiers">
            true
        </property>
        <property name="format_sql">
            false
        </property>
        <property name="use_sql_comments">
            false
        </property>
        <mapping class="db.TestDB01" />
        <mapping class="db.TestDB02" />
        <mapping class="db.TestDB03" />

    </session-factory>
</hibernate-configuration>
Users - TestDB01
import lombok.Getter;
import lombok.Setter;
import org.hibernate.annotations.Cascade;

import javax.persistence.*;
import java.util.ArrayList;
import java.util.List;

@Entity
@Table(name = "users", schema = "tdb")
public class TestDB01 {

	@Id
	@GeneratedValue(strategy = GenerationType.IDENTITY)
	@Getter	@Setter	private int id;
	@Column(name = "name")
	@Getter	@Setter	private String name;

	@Column(name = "age")
	@Getter	@Setter	private int age;

	@OnDelete(action = OnDeleteAction.CASCADE)
	@OneToMany(mappedBy = "user")
	@Getter	@Setter	private List<TestDB02> autos;

	public TestDB01() {
	}

	public TestDB01(String name, int age) {
		this.name = name;
		this.age = age;
		autos = new ArrayList<>();
	}

}
Autos - TestDB02
import lombok.Getter;
import lombok.Setter;
import javax.persistence.*;

@Entity
@Table(name = "autos")
public class TestDB02 {
	@Id
	@GeneratedValue(strategy = GenerationType.IDENTITY)
	@Getter	@Setter	private int id;

	@Column (name = "model")
	@Getter	@Setter	private String model;

	@Column (name = "color")
	@Getter	@Setter	private String color;

	@ManyToOne(fetch = FetchType.LAZY)
	@JoinColumn(name = "user_id")
	@Getter	@Setter	private TestDB01 user;

	public TestDB02() {
	}

	public TestDB02(String model, String color) {
		this.model = model;
		this.color = color;
	}
}

Hibernate attempt do work, but order of sql is wrong:

  1. Hibernate: drop table if exists tdb.users
  2. Hibernate: alter table autos drop foreign key FKmx3qhsa37wyfkttnpc9niyb7t
    So, it gove me this
Summary
Nov 09, 2018 1:57:47 PM org.hibernate.tool.schema.internal.ExceptionHandlerLoggedImpl handleException
WARN: GenerationTarget encountered exception accepting command : Error executing DDL "drop table if exists `tdb`.`users`" via JDBC Statement
org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL "drop table if exists `tdb`.`users`" via JDBC Statement
	at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:67)
	at org.hibernate.tool.schema.internal.SchemaDropperImpl.applySqlString(SchemaDropperImpl.java:375)
	at org.hibernate.tool.schema.internal.SchemaDropperImpl.applySqlStrings(SchemaDropperImpl.java:359)
	at org.hibernate.tool.schema.internal.SchemaDropperImpl.dropFromMetadata(SchemaDropperImpl.java:241)
	at org.hibernate.tool.schema.internal.SchemaDropperImpl.performDrop(SchemaDropperImpl.java:154)
	at org.hibernate.tool.schema.internal.SchemaDropperImpl.doDrop(SchemaDropperImpl.java:126)
	at org.hibernate.tool.schema.internal.SchemaDropperImpl.doDrop(SchemaDropperImpl.java:112)
	at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:144)
	at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:72)
	at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:310)
	at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:467)
	at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:708)
	at db.HibernateSessionFactoryUtil.getSessionFactory(HibernateSessionFactoryUtil.java:22)
	at db.UserDao.saveTest(UserDao.java:64)
	at db.UserService.saveTest(UserService.java:41)
	at Main.attempt5(Main.java:111)
	at Main.main(Main.java:15)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

Caused by: java.sql.SQLIntegrityConstraintViolationException: Cannot delete or update a parent row: a foreign key constraint fails
	at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:117)
	at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97)
	at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122)
	at com.mysql.cj.jdbc.StatementImpl.executeInternal(StatementImpl.java:782)

FK is correct. If i run manualy this two sql, only in reverce order, it will be work fine.
So, what i done wrong?

P.S. If i set-up hibernate.hbm2ddl.auto to “update”, then hibernate will be give me Exceptions, that “table already exist” (why it does? In this mode hibernate must attempt create table if it exist?)

That could be because the tables in the DB don’t match the ones in the Hibernate mapping.

As for this issue:

Caused by: java.sql.SQLIntegrityConstraintViolationException: Cannot delete or update a parent row: a foreign key constraint fails

Your DB contains some other table which has a FK to users so dropping the users table fails.

Sorry, name in DB and Classes is matches (i it see in my IDE)
I mean it : @Table(name = “users”, schema = “tdb”) - it match with name of table…
If cause was be so easy, then i no wrote this topic :frowning:

Sorry, i no see this in my DB or model
Capture

Facing same issue here. Help is appreciated.

Try to replicate the problem using this test case template.

Wow! I checked repo and code from your link and attempt use…
So, test worked fine, and, after, i used persistence.xml in my project (for my test-db, user, driver, pass).
And it now working without trouble in “update”-mode!

persistance.xml
<persistence-unit name="test_ast_db_2" transaction-type="RESOURCE_LOCAL">

        <description>Hibernate test case template Persistence Unit</description>
        <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>

        <exclude-unlisted-classes>false</exclude-unlisted-classes>

        <properties>
            <property name="hibernate.archive.autodetection" value="class, hbm"/>

            <!--<property name="hibernate.dialect" value="org.hibernate.dialect.H2Dialect"/>-->
            <property name="hibernate.dialect" value="org.hibernate.dialect.MySQL57Dialect"/>
            <!--<property name="hibernate.connection.driver_class" value="org.h2.Driver"/>-->
            <property name="hibernate.connection.driver_class" value="com.mysql.cj.jdbc.Driver"/>
            <!--<property name="hibernate.connection.url" value="jdbc:h2:mem:db1;DB_CLOSE_DELAY=-1"/>-->
            <property name="hibernate.connection.url" value="jdbc:mysql://192.168.1.29:3306/tdb?autoReconnect=true&amp;useSSL=false"/>
            <!--<property name="hibernate.connection.username" value="sa"/>-->
            <property name="hibernate.connection.username" value="rt"/>
            <property name="hibernate.connection.password" value="y4OjNKOI9xnMXuV20uGm" />

            <property name="hibernate.connection.pool_size" value="5"/>

            <property name="hibernate.show_sql" value="false"/>
            <property name="hibernate.format_sql" value="true"/>
            <property name="hibernate.hbm2ddl.auto" value="update"/>

            <property name="hibernate.max_fetch_depth" value="5"/>

            <property name="hibernate.cache.region_prefix" value="hibernate.test"/>
            <property name="hibernate.cache.region.factory_class"
                      value="org.hibernate.testing.cache.CachingRegionFactory"/>

            <!--NOTE: hibernate.jdbc.batch_versioned_data should be set to false when testing with Oracle-->
            <property name="hibernate.jdbc.batch_versioned_data" value="true"/>

            <property name="javax.persistence.validation.mode" value="NONE"/>
            <property name="hibernate.service.allow_crawling" value="false"/>
            <property name="hibernate.session.events.log" value="true"/>
        </properties>

    </persistence-unit>

So, great thanks to you!
Conclusions - before, i wrote wrong configuration…

try to recemplate with this Bookzz