当前位置: 首页 > 知识库问答 >
问题:

SpringBoot Hibernate+MySQL问题

宋稳
2023-03-14
com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column 'user0_.security_level' in 'field list'
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_121]
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_121]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_121]
at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_121]
at com.mysql.jdbc.Util.handleNewInstance(Util.java:425) ~[mysql-connector-java-5.1.45.jar:5.1.45]
at com.mysql.jdbc.Util.getInstance(Util.java:408) ~[mysql-connector-java-5.1.45.jar:5.1.45]
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:944) ~[mysql-connector-java-5.1.45.jar:5.1.45]
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3973) ~[mysql-connector-java-5.1.45.jar:5.1.45]
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3909) ~[mysql-connector-java-5.1.45.jar:5.1.45]
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2527) ~[mysql-connector-java-5.1.45.jar:5.1.45]
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2680) ~[mysql-connector-java-5.1.45.jar:5.1.45]
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2484) ~[mysql-connector-java-5.1.45.jar:5.1.45]
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1858) ~[mysql-connector-java-5.1.45.jar:5.1.45]
at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1966) ~[mysql-connector-java-5.1.45.jar:5.1.45]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_121]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_121]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_121]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_121]
at org.apache.tomcat.jdbc.pool.StatementFacade$StatementProxy.invoke(StatementFacade.java:114) ~[tomcat-jdbc-8.5.27.jar:na]
at com.sun.proxy.$Proxy92.executeQuery(Unknown Source) ~[na:na]
at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.extract(ResultSetReturnImpl.java:70) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.loader.Loader.getResultSet(Loader.java:2117) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1900) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1876) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.loader.Loader.doQuery(Loader.java:919) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:336) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.loader.Loader.doList(Loader.java:2617) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.loader.Loader.doList(Loader.java:2600) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2429) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.loader.Loader.list(Loader.java:2424) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:501) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.hql.internal.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:371) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.engine.query.spi.HQLQueryPlan.performList(HQLQueryPlan.java:216) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1326) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.internal.QueryImpl.list(QueryImpl.java:87) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.jpa.internal.QueryImpl.list(QueryImpl.java:606) ~[hibernate-entitymanager-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.jpa.internal.QueryImpl.getResultList(QueryImpl.java:483) ~[hibernate-entitymanager-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.jpa.criteria.compile.CriteriaQueryTypeQueryAdapter.getResultList(CriteriaQueryTypeQueryAdapter.java:50) ~[hibernate-entitymanager-5.0.12.Final.jar:5.0.12.Final]
at org.springframework.data.jpa.repository.support.SimpleJpaRepository.findAll(SimpleJpaRepository.java:329) ~[spring-data-jpa-1.11.10.RELEASE.jar:na]
at org.springframework.data.jpa.repository.support.SimpleJpaRepository.findAll(SimpleJpaRepository.java:74) ~[spring-data-jpa-1.11.10.RELEASE.jar:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_121]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_121]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_121]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_121]
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.executeMethodOn(RepositoryFactorySupport.java:513) ~[spring-data-commons-1.13.10.RELEASE.jar:na]
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:498) ~[spring-data-commons-1.13.10.RELEASE.jar:na]
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:475) ~[spring-data-commons-1.13.10.RELEASE.jar:na]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:56) ~[spring-data-commons-1.13.10.RELEASE.jar:na]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99) ~[spring-tx-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:282) ~[spring-tx-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96) ~[spring-tx-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:136) ~[spring-tx-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:133) ~[spring-data-jpa-1.11.10.RELEASE.jar:na]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92) ~[spring-aop-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:57) ~[spring-data-commons-1.13.10.RELEASE.jar:na]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213) ~[spring-aop-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at com.sun.proxy.$Proxy86.findAll(Unknown Source) ~[na:na]
at com.rcs.ticket.service.UserService.listUsers(UserService.java:19) ~[classes/:na]
at com.rcs.ticket.controller.UserController.list(UserController.java:23) ~[classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_121]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_121]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_121]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_121]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133) ~[spring-web-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:97) ~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) ~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) ~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) ~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967) ~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901) ~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) ~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) ~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:635) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) ~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.5.27.jar:8.5.27]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:108) ~[spring-web-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81) ~[spring-web-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) ~[spring-web-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.14.RELEASE.jar:4.3.14.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.27.jar:8.5.27]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504) [tomcat-embed-core-8.5.27.jar:8.5.27]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.27.jar:8.5.27]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) [tomcat-embed-core-8.5.27.jar:8.5.27]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.27.jar:8.5.27]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.27.jar:8.5.27]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803) [tomcat-embed-core-8.5.27.jar:8.5.27]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.27.jar:8.5.27]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:790) [tomcat-embed-core-8.5.27.jar:8.5.27]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459) [tomcat-embed-core-8.5.27.jar:8.5.27]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.27.jar:8.5.27]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_121]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_121]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.27.jar:8.5.27]
at java.lang.Thread.run(Thread.java:745) [na:1.8.0_121]
2018-02-13 11:07:34.069 DEBUG 6584 --- [nio-8080-exec-2] org.hibernate.SQL                        : 
/* select
    generatedAlias0 
from
    User as generatedAlias0 */ select
        user0_.id as id1_0_,
        user0_.createdate as createda2_0_,
        user0_.email as email3_0_,
        user0_.password as password4_0_,
        user0_.security_level as security5_0_,
        user0_.username as username6_0_ 
    from
        user user0_

Hibernate:/*select generatedAlias0 from User为generatedAlias0*/select user0_.ID为id1_0_,user0_.CREATEDATE为createda2_0_,user0_.Email为email3_0_,user0_.PASSWORD为password4_0_,user0_.Security_LEVEL为security5_0_,user0_.USERNAME为username6_0_from User USER0_2018-02-13 11:07:34.086 WARN 6584---[nio-8080-exec-2]O.H.Engine.jdbc.spi.SQLEXCEPTIONHELPER:SQL错误:1054,SQLSTATE:42S22 2018-02-13 13 11:07:34.086错误6584---[nio-8080-exec-2]O.H.Engine.jdbc.spi.SqlexCeptionHelper:“Field List”中的列“user0_.security_level”未知

这是我的实体定义。

@Entity
@Table(name = "user")
public class User implements Serializable{

  @Id
  @GeneratedValue(strategy=GenerationType.IDENTITY)
  private Integer id;
  private String username;
  private String password;
  private String email;
  @Column(name="createdate")
  @Temporal(TemporalType.TIMESTAMP)
  private Date createdate;
  @Column(name="securityLevel")
  private Integer securityLevel;

  public Integer getId() {
    return id;
  }

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

  public String getUsername() {
    return username;
  }

  public void setUsername(String username) {
    this.username = username;
  }

  public String getPassword() {
    return password;
  }

  public void setPassword(String password) {
    this.password = password;
  }

  public String getEmail() {
    return email;
  }

  public void setEmail(String email) {
    this.email = email;
  }

  public Date getcreatedate() {
    return createdate;
  }

  public void setcreatedate(Date createdate) {
    this.createdate = createdate;
  }

  public Integer getSecurityLevel() {
    return securityLevel;
  }

  public void setSecurityLevel(Integer securityLevel) {
    this.securityLevel = securityLevel;
  }

  public User(){
  }

  public User(Integer id, String username, String password, String email, Date createdate,  Integer securityLevel) {
    this.id = id;
    this.username = username;
    this.password = password;
    this.email = email;
    this.createdate = createdate;
    this.securityLevel = securityLevel;
  }
}

这是我的表格结构。用户表定义1

我认为问题发生在场映射中,但不知道如何解决。

共有1个答案

苍意智
2023-03-14

您所体验到的是spring-boot实现与PhysicalNamingStrategyImplicitNamingStrategy两者之间的细微差别,它们最终不同于Hibernate的默认值。

作为一个小历史,spring-boot试图通过这些策略的实现来模拟较早的Hibernate行为,以简化遗留应用程序的升级过程。

他们的策略本质上是将securitylevel转换为数据库级别的security_level,而不是像默认的hibernate实现那样是显式的通过。

您可以尝试在spring配置中覆盖它们的策略定义,以使用Hibernate附带的默认策略,看看这是否解决了您的冲突。

感兴趣的两个spring-boot设置是:

spring.jpa.hibernate.naming.physical-strategy
spring.jpa.hibernate.naming.implicit-strategy

Hibernate默认值为:

org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl
org.hibernate.boot.model.naming.ImplicitNamingStrategyJpaCompliantImpl
 类似资料:
  • 这是我试图制作的表格: 创建表Customer(customer_reference int UNIQUE AUTO_INCREMENT,主键(customer_reference),名字VARCHAR(20),姓氏VARCHAR(20),联系人VARCHAR(15),电子邮件VARCHAR(50),建筑物VARCHAR(5),道路VARCHAR(40),城市VARCHAR(30),邮政编码VAR

  • 问题内容: 我在理解如何执行一些INSERT SELECT时有些困难。 例如我有两个表。 现在,假设我要向表网站添加另一个查询。我得到两个变量,可以说: 我想从用户表中选择John的ID,然后在一条语句中将其插入网站表中。 我该怎么做? 问题答案: 假设您的变量已经正确地转义并且没有注入:

  • 问题内容: 如标题所述,我在java和mysql之间有问题 mysql数据库,表和列是utf8_unicode_ci。我有一个应用程序,它从xml中获取一些输入,然后编写查询… 此方法返回包含一个或多个SQL插入查询的String数组。然后 和和特殊字符都存储为? 因此特殊字符无法正确存储: 存储为 存储为 有什么建议吗? 谢谢 问题答案: 解决了,我忘了在初始化Connection时添加编码:

  • 问题内容: 昨晚,我的MySQL服务器意外关闭。尝试重新启动时(带有-我是root),它只是挂起。使用命令,我得到: 错误2002(HY000):无法通过套接字’/var/run/mysqld/mysqld.sock’(2)连接到本地MySQL服务器。 然后,我尝试手动启动守护程序()。提示将挂起大约2秒钟,然后返回。在仔细检查错误日志时,我得到: 然后,我尝试,和。没运气。 我环顾四周,找不到解

  • 我是php新手,对此我有问题: 错误: 非常感谢。

  • 问题内容: 我一直使用ISO-8859-1编码,但是现在要转到UTF-8。 不幸的是我无法正常工作。 我的MySQL数据库是UTF-8,我的PHP文档是用UTF-8编码的,我设置了UTF-8字符集,但仍然无法使用。 (像æ/ø/å这样的特殊字符不起作用) 希望你们能提供帮助! 问题答案: 确保与数据库的连接也使用此字符集: 根据php.net 的文档: 另请参见:http : //nl3.php.