为什么对 oracle 表 ALL_TAB_COLUMNS 的本机查询由于列无效而失败？

Question

为什么我在 Spring Boot Hibernate createNativeQuery 中收到此错误 Invalid column name？我正在尝试从 oracle 数据库中获取表信息。我将我的查询放入 db eaver 它的成功，请告诉我本机查询的最佳实践如何...

Hibernate: SELECT TABLE_NAME, COLUMN_NAME, DATA_TYPE FROM ALL_TAB_COLUMNS WHERE TABLE_NAME='BPN_AKTA'
2020-09-25 10:27:53.005  WARN 60208 --- [nio-8080-exec-2] o.h.engine.jdbc.spi.SqlExceptionHelper   : SQL Error: 17006, SQLState: 99999
2020-09-25 10:27:53.005 ERROR 60208 --- [nio-8080-exec-2] o.h.engine.jdbc.spi.SqlExceptionHelper   : Invalid column name
2020-09-25 10:27:53.006 ERROR 60208 --- [nio-8080-exec-2] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is javax.persistence.PersistenceException: org.hibernate.exception.GenericJDBCException: could not execute query] with root cause

java.sql.SQLException: Invalid column name

Query q= em.createNativeQuery("SELECT TABLE_NAME, COLUMN_NAME, DATA_TYPE FROM ALL_TAB_COLUMNS WHERE TABLE_NAME='PC'",QueryTableAttModel.class);
List<QueryTableAttModel> tableColl =  q.getResultList();

我的模特

@Entity(name="ALL_TAB_COLUMNS")
public class QueryTableAttModel {

    public String getTABLE_NAME() {
        return TABLE_NAME;
    }

    public void setTABLE_NAME(String TABLE_NAME) {
        this.TABLE_NAME = TABLE_NAME;
    }


    public String getCOLUMN_NAME() {
        return COLUMN_NAME;
    }

    public void setCOLUMN_NAME(String COLUMN_NAME) {
        this.COLUMN_NAME = COLUMN_NAME;
    }


    public String getDATA_TYPE() {
        return DATA_TYPE;
    }

    public void setDATA_TYPE(String DATA_TYPE) {
        this.DATA_TYPE = DATA_TYPE;
    }

    private String TABLE_NAME;
    private String COLUMN_NAME;
    private String DATA_TYPE;
    private String id;

    @Id
    public String getId() {
        return id;
    }

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

Answer 1

问题是表ALL_TAB_COLUMNS没有单列主键。您应该使用基于OWNER、TABLE_NAME、COLUMN_NAME 列的复合主键。

例如，您可以将@IdClass annotation 用于复合主键映射：

@Entity
@Table(name = "ALL_TAB_COLUMNS")
@IdClass(QueryTableAttModelPK.class)
public class QueryTableAttModel
{
   private String owner;
   private String tableName;
   private String columnName;
   private String dataType;
   
   public QueryTableAttModel()
   {
   }
   
   @Id
   @Column(name = "OWNER")
   public String getOwner()
   {
      return owner;
   }
   public void setOwner(String owner)
   {
      this.owner = owner;
   }

   @Id
   @Column(name = "TABLE_NAME")
   public String getTableName()
   {
      return tableName;
   }
   public void setTableName(String tableName)
   {
      this.tableName = tableName;
   }

   @Id
   @Column(name = "COLUMN_NAME")
   public String getColumnName()
   {
      return columnName;
   }
   public void setColumnName(String columnName)
   {
      this.columnName = columnName;
   }

   @Column(name = "DATA_TYPE")
   public String getDataType()
   {
      return dataType;
   }
   public void setDataType(String dataType)
   {
      this.dataType = dataType;
   }
}

QueryTableAttModelPK 类在哪里

import java.io.Serializable;
import java.util.Objects;

public class QueryTableAttModelPK implements Serializable
{
   private String owner;
   private String tableName;
   private String columnName;
   
   public QueryTableAttModelPK()
   {
   }
   
   public QueryTableAttModelPK(String owner, String tableName, String columnName)
   {
      this.owner = owner;
      this.tableName = tableName;
      this.columnName = columnName;
   }

   public String getOwner()
   {
      return owner;
   }
   public void setOwner(String owner)
   {
      this.owner = owner;
   }

   public String getTableName()
   {
      return tableName;
   }
   public void setTableName(String tableName)
   {
      this.tableName = tableName;
   }

   public String getColumnName()
   {
      return columnName;
   }
   public void setColumnName(String columnName)
   {
      this.columnName = columnName;
   }
   
   @Override
   public boolean equals(Object obj) {
      if (this == obj) return true;
      if (obj == null) return false;
      if (getClass() != obj.getClass()) return false;
      
      QueryTableAttModelPK other = (QueryTableAttModelPK) obj;
      return Objects.equals(owner, other.owner) 
          && Objects.equals(tableName, other.tableName)
          && Objects.equals(columnName, other.columnName);
   }

   @Override
   public int hashCode() {
      return Objects.hash(owner, tableName, columnName);
   }
}

然后您可以使用本机查询：

List<QueryTableAttModel> results = em.createNativeQuery(
   "select OWNER, TABLE_NAME, COLUMN_NAME, DATA_TYPE from ALL_TAB_COLUMNS where TABLE_NAME = :table",
   QueryTableAttModel.class)
.setParameter("table", "ALL_TAB_COLUMNS")
.getResultList();

jpql/hql 查询：

List<QueryTableAttModel> results = em.createQuery(
   "select q from QueryTableAttModel q where q.tableName = :table",
   QueryTableAttModel.class)
.setParameter("table", "ALL_TAB_COLUMNS")
.getResultList();

或者通过PK找实体：

QueryTableAttModel qTable = em.find(
   QueryTableAttModel.class,
   new QueryTableAttModelPK("SYS", "ALL_TAB_COLUMNS", "CHAR_LENGTH")
);