Eclipse + Hibernate + Building / Running Operations на Oracle SQL - разработчик очень медленно - PullRequest
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Eclipse + Hibernate + Building / Running Operations на Oracle SQL - разработчик очень медленно

0 голосов
/ 18 июня 2020

первое примечание: я тоже смотрел сюда: запуск гибернации очень медленный медленное получение гибернации Postgres соединение ограничение гибернации уже существует поиск также в другом месте . К сожалению, лучше не стало. Свойство created_key тоже не помогло (более подробное объяснение позже).

Я делаю Учебное пособие по Hibernate, и моя сборка / Запуск от имени занимает до 2 минут. Я на Windows 10, Eclipse, Hibernate. Работа с 2-х минутным временем сборки - это большой облом, даже когда мой код «работает». Я надеюсь, что с этим постом все в порядке, пока еще не так много писали. Спасибо заранее!

Мой код: 

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Random;

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

import org.hibernate.Criteria;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;
import org.hibernate.query.NativeQuery;
import org.hibernate.query.Query;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.stat.SessionStatistics;
import org.hibernate.stat.Statistics;

public class QueryPractice
{
    public static void main (String[] args)
    {
        Configuration config = new Configuration().configure().
                addAnnotatedClass(Student.class).
                addAnnotatedClass(Laptop.class);
        ServiceRegistry registry = new StandardServiceRegistryBuilder().applySettings(config.getProperties()).build();
        SessionFactory sF = config.buildSessionFactory(registry);
        Session session = sF.openSession();

        Statistics stats = sF.getStatistics(); 

        session.beginTransaction();

        NativeQuery querySQL2 = session.createNativeQuery("SELECT sName,sMarks "
                +                                   "FROM student");

        querySQL2.setResultTransformer(Criteria.ALIAS_TO_ENTITY_MAP);
        List students = querySQL2.getResultList();

        for (Object o : students)
        {
            System.out.println(o);
            Map m = (Map)o;
            System.out.println(m.get("SNAME") + " : " + m.get("SMARKS"));
        }

        stats.getSessionOpenCount();
        stats.logSummary();

        session.getTransaction().commit();
    }
}

Это мой файл hibernate.cfg. xml (пароль и имя пользователя изменены;)): 

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>
        <property name="hibernate.connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
        <property name="hibernate.connection.password">MyPassword</property>
        <property name="hibernate.connection.url">jdbc:oracle:thin:@localhost:1521:orcl</property>
        <property name="hibernate.connection.username">c##MyUser</property>
        <property name="hibernate.dialect">org.hibernate.dialect.Oracle10gDialect</property>
        <property name="hbm2ddl.auto">update</property>
        <property name="show_sql">true</property>
        <property name="hibernate.generate_statistics">true</property>
        <property name="hibernate.jdbc.use_get_generated_keys">true</property>
        <property name="hibernate.temp.use_jdbc_metadata_defaults">false</property>
        <property name="hibernate.jdbc.use_scrollable_resultset">true</property>
    </session-factory>
</hibernate-configuration>

Если я использую <property name="hibernate.jdbc.use_get_generated_keys">true</property>, он становится быстрее, но возникают ошибки, касающиеся ограничений, и я также не знаю, как это исправить. Мой код, похоже, работает, и я получаю информацию из базы данных. Если я не добавлю свойство, я не получу этих исключений, но это займет вечность.

сокращенный вывод без свойства сгенерированных ключей: 

This came in an instant:
Jun 18, 2020 2:24:55 PM org.hibernate.Version logVersion
INFO: HHH000412: Hibernate ORM core version 5.4.17.Final
Jun 18, 2020 2:24:55 PM org.hibernate.annotations.common.reflection.java.JavaReflectionManager <clinit>
INFO: HCANN000001: Hibernate Commons Annotations {5.1.0.Final}
Jun 18, 2020 2:24:55 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
WARN: HHH10001002: Using Hibernate built-in connection pool (not for production use!)
Jun 18, 2020 2:24:55 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001005: using driver [oracle.jdbc.driver.OracleDriver] at URL [jdbc:oracle:thin:@localhost:1521:orcl]
Jun 18, 2020 2:24:55 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001001: Connection properties: {password=****, user=c##HupfDohle}
Jun 18, 2020 2:24:55 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001003: Autocommit mode: false
Jun 18, 2020 2:24:55 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl$PooledConnections <init>
INFO: HHH000115: Hibernate connection pool size: 20 (min=1)
Jun 18, 2020 2:24:56 PM org.hibernate.dialect.Dialect <init>
INFO: HHH000400: Using dialect: org.hibernate.dialect.Oracle10gDialect

Output after 1 min:
Jun 18, 2020 2:25:44 PM org.hibernate.resource.transaction.backend.jdbc.internal.DdlTransactionIsolatorNonJtaImpl getIsolatedConnection
INFO: HHH10001501: Connection obtained from JdbcConnectionAccess [org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator$ConnectionProviderJdbcConnectionAccess@637791d] for (non-JTA) DDL execution was not in auto-commit mode; the Connection 'local transaction' will be committed and the Connection will be set into auto-commit mode.

Output after another minute:
Jun 18, 2020 2:26:32 PM org.hibernate.engine.transaction.jta.platform.internal.JtaPlatformInitiator initiateService
INFO: HHH000490: Using JtaPlatform implementation: [org.hibernate.engine.transaction.jta.platform.internal.NoJtaPlatform]
Hibernate: SELECT sName,sMarks FROM student
{SNAME=Nameless fool number 1, SMARKS=65}
Hibernate: SELECT sName,sMarks FROM student
{SNAME=Nameless fool number 1, SMARKS=65}
Nameless fool number 1 : 65
...
{SNAME=Nameless fool number 50, SMARKS=60}
Nameless fool number 50 : 60
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000161: Logging statistics....
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000251: Start time: 1592483192761
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000242: Sessions opened: 1
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000241: Sessions closed: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000266: Transactions: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000258: Successful transactions: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000187: Optimistic lock failures: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000105: Flushes: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000048: Connections obtained: 1
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000253: Statements prepared: 1
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000252: Statements closed: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000239: Second level cache puts: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000237: Second level cache hits: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000238: Second level cache misses: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000079: Entities loaded: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000080: Entities updated: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000078: Entities inserted: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000076: Entities deleted: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000077: Entities fetched (minimize this): 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000033: Collections loaded: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000036: Collections updated: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000035: Collections removed: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000034: Collections recreated: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000032: Collections fetched (minimize this): 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000438: NaturalId cache puts: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000439: NaturalId cache hits: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000440: NaturalId cache misses: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000441: Max NaturalId query time: 0ms
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000442: NaturalId queries executed to database: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000210: Queries executed to database: 1
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000215: Query cache puts: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000433: update timestamps cache puts: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000434: update timestamps cache hits: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000435: update timestamps cache misses: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000213: Query cache hits: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000214: Query cache misses: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000173: Max query time: 8ms
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000492: Query plan cache hits: 0
Jun 18, 2020 2:26:32 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000493: Query plan cache misses: 0

вывод со свойством сгенерированных ключей: 

Jun 18, 2020 1:49:45 PM org.hibernate.Version logVersion
INFO: HHH000412: Hibernate ORM core version 5.4.17.Final
Jun 18, 2020 1:49:45 PM org.hibernate.annotations.common.reflection.java.JavaReflectionManager <clinit>
INFO: HCANN000001: Hibernate Commons Annotations {5.1.0.Final}
Jun 18, 2020 1:49:45 PM org.hibernate.dialect.Dialect <init>
INFO: HHH000400: Using dialect: org.hibernate.dialect.Oracle10gDialect
Jun 18, 2020 1:49:46 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
WARN: HHH10001002: Using Hibernate built-in connection pool (not for production use!)
Jun 18, 2020 1:49:46 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001005: using driver [oracle.jdbc.driver.OracleDriver] at URL [jdbc:oracle:thin:@localhost:1521:orcl]
Jun 18, 2020 1:49:46 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001001: Connection properties: {password=****, user=c##HupfDohle}
Jun 18, 2020 1:49:46 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001003: Autocommit mode: false
Jun 18, 2020 1:49:46 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl$PooledConnections <init>
INFO: HHH000115: Hibernate connection pool size: 20 (min=1)
Jun 18, 2020 1:49:46 PM org.hibernate.resource.transaction.backend.jdbc.internal.DdlTransactionIsolatorNonJtaImpl getIsolatedConnection
INFO: HHH10001501: Connection obtained from JdbcConnectionAccess [org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator$ConnectionProviderJdbcConnectionAccess@1c067c0d] for (non-JTA) DDL execution was not in auto-commit mode; the Connection 'local transaction' will be committed and the Connection will be set into auto-commit mode.
Hibernate: create table Laptop (lId number(10,0) not null, lName varchar2(255 char), primary key (lId))
Jun 18, 2020 1:50:35 PM org.hibernate.tool.schema.internal.ExceptionHandlerLoggedImpl handleException
WARN: GenerationTarget encountered exception accepting command : Error executing DDL "create table Laptop (lId number(10,0) not null, lName varchar2(255 char), primary key (lId))" via JDBC Statement
org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL "create table Laptop (lId number(10,0) not null, lName varchar2(255 char), primary key (lId))" via JDBC Statement
    at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:67)
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applySqlString(AbstractSchemaMigrator.java:559)
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applySqlStrings(AbstractSchemaMigrator.java:504)
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.createTable(AbstractSchemaMigrator.java:277)
    at org.hibernate.tool.schema.internal.GroupedSchemaMigratorImpl.performTablesMigration(GroupedSchemaMigratorImpl.java:71)
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.performMigration(AbstractSchemaMigrator.java:207)
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.doMigration(AbstractSchemaMigrator.java:114)
    at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:184)
    at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:73)
    at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:316)
    at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:469)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:708)
    at com.HupfDohle.demoHibernate.QueryPractice.main(QueryPractice.java:34)
Caused by: java.sql.SQLSyntaxErrorException: ORA-00955: name is already used by an existing object
...shortened...
    ... 12 more
Caused by: Error : 955, Position : 13, Sql = create table Laptop (lId number(10,0) not null, lName varchar2(255 char), primary key (lId)), OriginalSql = create table Laptop (lId number(10,0) not null, lName varchar2(255 char), primary key (lId)), Error Msg = ORA-00955: name is already used by an existing object

    at oracle.jdbc.driver.T4CTTIoer11.processError(T4CTTIoer11.java:513)
    ... 25 more

Hibernate: create table Laptop_Student (laptop_lId number(10,0) not null, student_sId number(10,0) not null)
Jun 18, 2020 1:50:35 PM org.hibernate.tool.schema.internal.ExceptionHandlerLoggedImpl handleException
WARN: GenerationTarget encountered exception accepting command : Error executing DDL "create table Laptop_Student (laptop_lId number(10,0) not null, student_sId number(10,0) not null)" via JDBC Statement
org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL "create table Laptop_Student (laptop_lId number(10,0) not null, student_sId number(10,0) not null)" via JDBC Statement
    at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:67)
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applySqlString(AbstractSchemaMigrator.java:559)
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applySqlStrings(AbstractSchemaMigrator.java:504)
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.createTable(AbstractSchemaMigrator.java:277)
    at org.hibernate.tool.schema.internal.GroupedSchemaMigratorImpl.performTablesMigration(GroupedSchemaMigratorImpl.java:71)
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.performMigration(AbstractSchemaMigrator.java:207)
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.doMigration(AbstractSchemaMigrator.java:114)
    at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:184)
    at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:73)
    at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:316)
    at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:469)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:708)
    at com.HupfDohle.demoHibernate.QueryPractice.main(QueryPractice.java:34)
Caused by: java.sql.SQLSyntaxErrorException: ORA-00955: name is already used by an existing object
...shortened
    ... 12 more
Caused by: Error : 955, Position : 13, Sql = create table Laptop_Student (laptop_lId number(10,0) not null, student_sId number(10,0) not null), OriginalSql = create table Laptop_Student (laptop_lId number(10,0) not null, student_sId number(10,0) not null), Error Msg = ORA-00955: name is already used by an existing object

    at oracle.jdbc.driver.T4CTTIoer11.processError(T4CTTIoer11.java:513)
    ... 25 more

Hibernate: create table Student (sId number(10,0) not null, sMarks number(10,0) not null, sName varchar2(255 char), primary key (sId))
Jun 18, 2020 1:50:35 PM org.hibernate.tool.schema.internal.ExceptionHandlerLoggedImpl handleException
WARN: GenerationTarget encountered exception accepting command : Error executing DDL "create table Student (sId number(10,0) not null, sMarks number(10,0) not null, sName varchar2(255 char), primary key (sId))" via JDBC Statement
org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL "create table Student (sId number(10,0) not null, sMarks number(10,0) not null, sName varchar2(255 char), primary key (sId))" via JDBC Statement
    at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:67)
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applySqlString(AbstractSchemaMigrator.java:559)
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applySqlStrings(AbstractSchemaMigrator.java:504)
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.createTable(AbstractSchemaMigrator.java:277)
    at org.hibernate.tool.schema.internal.GroupedSchemaMigratorImpl.performTablesMigration(GroupedSchemaMigratorImpl.java:71)
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.performMigration(AbstractSchemaMigrator.java:207)
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.doMigration(AbstractSchemaMigrator.java:114)
    at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:184)
    at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:73)
    at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:316)
    at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:469)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:708)
    at com.HupfDohle.demoHibernate.QueryPractice.main(QueryPractice.java:34)
Caused by: java.sql.SQLSyntaxErrorException: ORA-00955: name is already used by an existing object
...shortened...
    ... 12 more
Caused by: Error : 955, Position : 13, Sql = create table Student (sId number(10,0) not null, sMarks number(10,0) not null, sName varchar2(255 char), primary key (sId)), OriginalSql = create table Student (sId number(10,0) not null, sMarks number(10,0) not null, sName varchar2(255 char), primary key (sId)), Error Msg = ORA-00955: name is already used by an existing object

    at oracle.jdbc.driver.T4CTTIoer11.processError(T4CTTIoer11.java:513)
    ... 25 more

Hibernate: alter table Laptop_Student add constraint FKhvjqy4vv92e83wcjqxyciuc2g foreign key (student_sId) references Student
Jun 18, 2020 1:50:35 PM org.hibernate.tool.schema.internal.ExceptionHandlerLoggedImpl handleException
WARN: GenerationTarget encountered exception accepting command : Error executing DDL "alter table Laptop_Student add constraint FKhvjqy4vv92e83wcjqxyciuc2g foreign key (student_sId) references Student" via JDBC Statement
org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL "alter table Laptop_Student add constraint FKhvjqy4vv92e83wcjqxyciuc2g foreign key (student_sId) references Student" via JDBC Statement
    at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:67)
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applySqlString(AbstractSchemaMigrator.java:559)
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applySqlStrings(AbstractSchemaMigrator.java:504)
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applyForeignKeys(AbstractSchemaMigrator.java:433)
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.performMigration(AbstractSchemaMigrator.java:249)
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.doMigration(AbstractSchemaMigrator.java:114)
    at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:184)
    at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:73)
    at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:316)
    at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:469)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:708)
    at com.HupfDohle.demoHibernate.QueryPractice.main(QueryPractice.java:34)
Caused by: java.sql.SQLSyntaxErrorException: ORA-02275: such a referential constraint already exists in the table

    ...shortened...
    ... 11 more
Caused by: Error : 2275, Position : 70, Sql = alter table Laptop_Student add constraint FKhvjqy4vv92e83wcjqxyciuc2g foreign key (student_sId) references Student, OriginalSql = alter table Laptop_Student add constraint FKhvjqy4vv92e83wcjqxyciuc2g foreign key (student_sId) references Student, Error Msg = ORA-02275: such a referential constraint already exists in the table

    at oracle.jdbc.driver.T4CTTIoer11.processError(T4CTTIoer11.java:513)
    ... 24 more

Hibernate: alter table Laptop_Student add constraint FKs3mxmv9qb3cei07bi1b0rmx3g foreign key (laptop_lId) references Laptop
Jun 18, 2020 1:50:35 PM org.hibernate.tool.schema.internal.ExceptionHandlerLoggedImpl handleException
WARN: GenerationTarget encountered exception accepting command : Error executing DDL "alter table Laptop_Student add constraint FKs3mxmv9qb3cei07bi1b0rmx3g foreign key (laptop_lId) references Laptop" via JDBC Statement
org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL "alter table Laptop_Student add constraint FKs3mxmv9qb3cei07bi1b0rmx3g foreign key (laptop_lId) references Laptop" via JDBC Statement
    at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:67)
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applySqlString(AbstractSchemaMigrator.java:559)
    at 
..shortened..

Jun 18, 2020 1:50:35 PM org.hibernate.engine.transaction.jta.platform.internal.JtaPlatformInitiator initiateService
INFO: HHH000490: Using JtaPlatform implementation: [org.hibernate.engine.transaction.jta.platform.internal.NoJtaPlatform]
Hibernate: SELECT sName,sMarks FROM student
{SNAME=Nameless fool number 1, SMARKS=65}
Nameless fool number 1 : 65
...
{SNAME=Nameless fool number 50, SMARKS=60}
Nameless fool number 50 : 60
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000161: Logging statistics....
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000251: Start time: 1592481035225
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000242: Sessions opened: 1
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000241: Sessions closed: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000266: Transactions: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000258: Successful transactions: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000187: Optimistic lock failures: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000105: Flushes: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000048: Connections obtained: 1
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000253: Statements prepared: 1
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000252: Statements closed: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000239: Second level cache puts: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000237: Second level cache hits: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000238: Second level cache misses: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000079: Entities loaded: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000080: Entities updated: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000078: Entities inserted: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000076: Entities deleted: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000077: Entities fetched (minimize this): 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000033: Collections loaded: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000036: Collections updated: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000035: Collections removed: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000034: Collections recreated: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000032: Collections fetched (minimize this): 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000438: NaturalId cache puts: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000439: NaturalId cache hits: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000440: NaturalId cache misses: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000441: Max NaturalId query time: 0ms
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000442: NaturalId queries executed to database: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000210: Queries executed to database: 1
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000215: Query cache puts: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000433: update timestamps cache puts: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000434: update timestamps cache hits: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000435: update timestamps cache misses: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000213: Query cache hits: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000214: Query cache misses: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000173: Max query time: 19ms
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000492: Query plan cache hits: 0
Jun 18, 2020 1:50:35 PM org.hibernate.stat.internal.StatisticsImpl logSummary
INFO: HHH000493: Query plan cache misses: 0
...