解决办法could not initialize a collection
错误信息
SQLGrammarException: could not initialize a collection
Caused by: java.sql.SQLException: [Microsoft][SQLServer 2000 Driver for JDBC][SQLServer]对象名 'EmployeeRole' 无效。


Role Class

package com.many_to_many_s;

import java.util.HashSet;
import java.util.Set;

/**
* Role entity.
*
* @author MyEclipse Persistence Tools
*/

public class Role implements java.io.Serializable {

// Fields

private String roleId;
private String roleName;

private Set employees = new HashSet(0);



public Set getEmployees() {
return employees;
}

public void setEmployees(Set employees) {
this.employees = employees;
}

// Property accessors

public String getRoleId() {
return this.roleId;
}

public void setRoleId(String roleId) {
this.roleId = roleId;
}

public String getRoleName() {
return this.roleName;
}

public void setRoleName(String roleName) {
this.roleName = roleName;
}

}

role.hbm.xml 中

<hibernate-mapping package="com.many_to_many_s">
<class name="Role" table="Role" schema="dbo" catalog="mypro">
<id name="roleId" type="java.lang.String">
<column name="roleID" length="50" />
<generator />
</id>
<property name="roleName" type="java.lang.String">
<column name="roleName" length="50" />
</property>


<set name="employees" table="EmployeeRole" >
<key column="roleID"></key>
<many-to-many column="operatorID" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!--
Mapping file autogenerated by MyEclipse Persistence Tools
-->
<hibernate-mapping package="com.many_to_many_s">
<class name="Employee" table="Employee" schema="dbo" catalog="mypro">
<id name="operatorId" type="java.lang.String">
<column name="operatorID" length="50" />
<generator />
</id>
<property name="employeeName" type="java.lang.String">
<column name="employeeName" length="50" />
</property>
<property name="password" type="java.lang.String">
<column name="password" length="50" />
</property>
<property name="operatorName" type="java.lang.String">
<column name="operatorName" length="50" />
</property>
<property name="birthDate" type="java.util.Date">
<column name="birthDate" length="23" />
</property>
<property name="orgId" type="java.lang.String">
<column name="orgID" length="50" />
</property>
<property name="ragDate" type="java.util.Date">
<column name="ragDate" length="23" />
</property>
<property name="createTime" type="java.util.Date">
<column name="createTime" length="23" />
</property>
<property name="lastModifyTime" type="java.util.Date">
<column name="lastModifyTime" length="23" />
</property>
<property name="status" type="java.lang.String">
<column name="status" length="50" />
</property>
<set name="roles" table="EmployeeRole">
<key column="operatorID"></key>
<many-to-many column="roleID" table="Role" schema="dbo" catalog="mypro">
<id name="roleId" type="java.lang.String">
改为
<hibernate-mapping package="com.many_to_many_s">
<class name="Role" table="Role" >
<id name="roleId" type="java.lang.String">

<!--去掉schema="dbo" catalog="mypro" -->


改为

Employee.hbm.xml

<hibernate-mapping package="com.many_to_many_s">
<class name="Employee" table="Employee" schema="dbo" catalog="mypro">
<id name="operatorId" type="java.lang.String">

<!--去掉schema="dbo" catalog="mypro" -->

改为

<hibernate-mapping package="com.many_to_many_s">
<class name="Employee" table="Employee" >
<id name="operatorId" type="java.lang.String">

原因解释

这是从Employee端查询其对应的Role

select
employees0_.roleID as roleID1_,
employees0_.operatorID as operatorID1_,
employee1_.operatorID as operatorID3_0_,
employee1_.employeeName as employee2_3_0_,
employee1_.password as password3_0_,
employee1_.operatorName as operator4_3_0_,
employee1_.birthDate as birthDate3_0_,
employee1_.orgID as orgID3_0_,
employee1_.ragDate as ragDate3_0_,
employee1_.createTime as createTime3_0_,
employee1_.lastModifyTime as lastModi9_3_0_,
employee1_.status as status3_0_
from
EmployeeRole employees0_ <------------注意这里 没有指定EmployeeRole属于的数据库名称,所有就会出现
Caused by: java.sql.SQLException: [Microsoft][SQLServer 2000 Driver for JDBC][SQLServer]对象名 'EmployeeRole' 无效。

left outer join
mypro.dbo.Employee employee1_
on employees0_.operatorID=employee1_.operatorID
where
employees0_.roleID=?

1 楼 gembler 2008-12-24 connection url 中写不是很爽，每种数据的写法可能不一样。
还是习惯在cfg.xml中用default_schema。
至于hbm.xml里的schema，特殊情况才用上，一般不用。