NHibernate 使用CreateSQLQuery进行查询
2013-11-27 14:16
501 查看
涉及的表:
Cake{
Id ,
CakeName
}
CakeSize{
CakeId,-为外键,对应Cake表的字段Id
Size
}
(其中ISession session = NHibernateHelper.GetCurrentSession();)
用法一(返回数值):
ISQLQuery query = session.CreateSQLQuery("SELECT COUNT(Id) AS C FROM Cake").AddScalar("C", NHibernateUtil.Int32);
int c = Convert.ToInt32(query.UniqueResult());
或int c = query.UniqueResult<int>;//使用此方法发现sql执行了两次,故不推荐使用。
用法二(返回对象实体):
ISQLQuery query = session.CreateSQLQuery("select * from cake c").AddEntity("CAKE.DataTransfer.Entities.Cake");
或ISQLQuery query = session.CreateSQLQuery("select * from cake c").AddEntity("c", "CAKE.DataTransfer.Entities.Cake");
或ISQLQuery query = session.CreateSQLQuery("select * from cake c").AddEntity(typeof(Cake));
或ISQLQuery query = session.CreateSQLQuery("select * from cake c").AddEntity("c", typeof(Cake));
或ISQLQuery query = session.CreateSQLQuery("select * from cake c").AddEntity("c", typeof(Cake), LockMode.Write);
IList<Cake> c = query.List<Cake>();
用法三(连表查询):
ISQLQuery query = session.CreateSQLQuery("select cs.* from cake c join CakeSize cs on cs.CakeId=c.Id")
.AddEntity("cs", typeof(CakeSize));
IList<CakeSize> cs = query.List<CakeSize>();
以上是一种常见的用法,通过该例子,相信大家心里也已经有个数了,也应该知道怎么操作这个sql了:)
但是过程中难免会遇到些问题,比如:
实例二(问题说明):
我需要执行例如这条sql语句:
select CreateTime,Address,Password, (case when EmailType = 0 then 'Gmail' when EmailType = 1 then 'Yahoo' when EmailType = 2 then 'Hotmail' else 'Other' end) as EmailType from MailInfo
1. 如果使用session.CreateQuery方法执行的话,你可能会遇到这样的错误:
错误:undefined alias or unknown mapping
ISession session = DAORepository.Instrance.DbSession;
string queryString = "select CreateTime,Address,Password, (case when EmailType = 0 then 'Gmail' when EmailType = 1 then 'Yahoo' when EmailType = 2 then 'Hotmail' else 'Other' end) as EmailType from MailInfo where status=0 Order by CreateTime desc";
IQuery query = session.CreateQuery(queryString;
IList lst = query.List();
2. 使用CreateSQLQuery方法执行:
错误:Return types of SQL query were not specified...
ISession session = DAORepository.Instrance.DbSession;
string queryString = "select CreateTime,Address,Password, (case when EmailType = 0 then 'Gmail' when EmailType = 1 then 'Yahoo' when EmailType = 2 then 'Hotmail' else 'Other' end) as EmailType from MailInfo where status=0 Order by CreateTime desc";
ISQLQuery query = session.CreateSQLQuery(queryString);
IList lst = query.List();
3. 使用CreateSQLQuery方法并指定返回字段值的类型,即使用AddScalar方法指定字段值类型:
错误:could not execute query...
ISession session = DAORepository.Instrance.DbSession;
string queryString = "select CreateTime,Address,Password, (case when EmailType = 0 then 'Gmail' when EmailType = 1 then 'Yahoo' when EmailType = 2 then 'Hotmail' else 'Other' end) as EmailType from MailInfo where status=0 Order by CreateTime desc";
ISQLQuery query = session.CreateSQLQuery(queryString).AddScalar("CreateTime",NHibernateUtil.String)
.AddScalar("Address",NHibernateUtil.String)
.AddScalar("Password",NHibernateUtil.String)
.AddScalar("EmailType",NHibernateUtil.Int32);
IList lst = query.List();
ISession session = DAORepository.Instrance.DbSession;
string queryString = "select CreateTime,Address,Password, (case when EmailType = 0 then 'Gmail' when EmailType = 1 then 'Yahoo' when EmailType = 2 then 'Hotmail' else 'Other' end) as EmailType from MailInfo where status=0 Order by CreateTime desc";
ISQLQuery query = session.CreateSQLQuery(queryString).AddScalar("CreateTime",NHibernateUtil.String)
.AddScalar("Address",NHibernateUtil.String)
.AddScalar("Password",NHibernateUtil.String)
.AddScalar("EmailType",NHibernateUtil.Int32);
IList lst = query.List();
注意:EmailType字段对应数据库的类型是int,这里我就误解为也应该映射为NHibernateUtil.Int32;
4. 解决问题:
把AddScalar方法的参数里一个属性改了一下:
ISession session = DAORepository.Instrance.DbSession;
string queryString = "select CreateTime,Address,Password, (case when EmailType = 0 then 'Gmail' when EmailType = 1 then 'Yahoo' when EmailType = 2 then 'Hotmail' else 'Other' end) as EmailType from MailInfo where status=0 Order by CreateTime desc";
ISQLQuery query = session.CreateSQLQuery(queryString).AddScalar("CreateTime",NHibernateUtil.String)
.AddScalar("Address",NHibernateUtil.String)
.AddScalar("Password",NHibernateUtil.String)
.AddScalar("EmailType",NHibernateUtil.String);
IList lst = query.List();
ISession session = DAORepository.Instrance.DbSession;
string queryString = "select CreateTime,Address,Password, (case when EmailType = 0 then 'Gmail' when EmailType = 1 then 'Yahoo' when EmailType = 2 then 'Hotmail' else 'Other' end) as EmailType from MailInfo where status=0 Order by CreateTime desc";
ISQLQuery query = session.CreateSQLQuery(queryString).AddScalar("CreateTime",NHibernateUtil.String)
.AddScalar("Address",NHibernateUtil.String)
.AddScalar("Password",NHibernateUtil.String)
.AddScalar("EmailType",NHibernateUtil.String);
IList lst = query.List();
注意:这里我将EmailType的类型映射改为了NHibernateUtil.String,实际上是与返回结果的EmailType值类型保持一致就OK了。
Cake{
Id ,
CakeName
}
CakeSize{
CakeId,-为外键,对应Cake表的字段Id
Size
}
(其中ISession session = NHibernateHelper.GetCurrentSession();)
用法一(返回数值):
ISQLQuery query = session.CreateSQLQuery("SELECT COUNT(Id) AS C FROM Cake").AddScalar("C", NHibernateUtil.Int32);
int c = Convert.ToInt32(query.UniqueResult());
或int c = query.UniqueResult<int>;//使用此方法发现sql执行了两次,故不推荐使用。
用法二(返回对象实体):
ISQLQuery query = session.CreateSQLQuery("select * from cake c").AddEntity("CAKE.DataTransfer.Entities.Cake");
或ISQLQuery query = session.CreateSQLQuery("select * from cake c").AddEntity("c", "CAKE.DataTransfer.Entities.Cake");
或ISQLQuery query = session.CreateSQLQuery("select * from cake c").AddEntity(typeof(Cake));
或ISQLQuery query = session.CreateSQLQuery("select * from cake c").AddEntity("c", typeof(Cake));
或ISQLQuery query = session.CreateSQLQuery("select * from cake c").AddEntity("c", typeof(Cake), LockMode.Write);
IList<Cake> c = query.List<Cake>();
用法三(连表查询):
ISQLQuery query = session.CreateSQLQuery("select cs.* from cake c join CakeSize cs on cs.CakeId=c.Id")
.AddEntity("cs", typeof(CakeSize));
IList<CakeSize> cs = query.List<CakeSize>();
以上是一种常见的用法,通过该例子,相信大家心里也已经有个数了,也应该知道怎么操作这个sql了:)
但是过程中难免会遇到些问题,比如:
实例二(问题说明):
我需要执行例如这条sql语句:
select CreateTime,Address,Password, (case when EmailType = 0 then 'Gmail' when EmailType = 1 then 'Yahoo' when EmailType = 2 then 'Hotmail' else 'Other' end) as EmailType from MailInfo
1. 如果使用session.CreateQuery方法执行的话,你可能会遇到这样的错误:
错误:undefined alias or unknown mapping
ISession session = DAORepository.Instrance.DbSession;
string queryString = "select CreateTime,Address,Password, (case when EmailType = 0 then 'Gmail' when EmailType = 1 then 'Yahoo' when EmailType = 2 then 'Hotmail' else 'Other' end) as EmailType from MailInfo where status=0 Order by CreateTime desc";
IQuery query = session.CreateQuery(queryString;
IList lst = query.List();
2. 使用CreateSQLQuery方法执行:
错误:Return types of SQL query were not specified...
ISession session = DAORepository.Instrance.DbSession;
string queryString = "select CreateTime,Address,Password, (case when EmailType = 0 then 'Gmail' when EmailType = 1 then 'Yahoo' when EmailType = 2 then 'Hotmail' else 'Other' end) as EmailType from MailInfo where status=0 Order by CreateTime desc";
ISQLQuery query = session.CreateSQLQuery(queryString);
IList lst = query.List();
3. 使用CreateSQLQuery方法并指定返回字段值的类型,即使用AddScalar方法指定字段值类型:
错误:could not execute query...
ISession session = DAORepository.Instrance.DbSession;
string queryString = "select CreateTime,Address,Password, (case when EmailType = 0 then 'Gmail' when EmailType = 1 then 'Yahoo' when EmailType = 2 then 'Hotmail' else 'Other' end) as EmailType from MailInfo where status=0 Order by CreateTime desc";
ISQLQuery query = session.CreateSQLQuery(queryString).AddScalar("CreateTime",NHibernateUtil.String)
.AddScalar("Address",NHibernateUtil.String)
.AddScalar("Password",NHibernateUtil.String)
.AddScalar("EmailType",NHibernateUtil.Int32);
IList lst = query.List();
ISession session = DAORepository.Instrance.DbSession;
string queryString = "select CreateTime,Address,Password, (case when EmailType = 0 then 'Gmail' when EmailType = 1 then 'Yahoo' when EmailType = 2 then 'Hotmail' else 'Other' end) as EmailType from MailInfo where status=0 Order by CreateTime desc";
ISQLQuery query = session.CreateSQLQuery(queryString).AddScalar("CreateTime",NHibernateUtil.String)
.AddScalar("Address",NHibernateUtil.String)
.AddScalar("Password",NHibernateUtil.String)
.AddScalar("EmailType",NHibernateUtil.Int32);
IList lst = query.List();
注意:EmailType字段对应数据库的类型是int,这里我就误解为也应该映射为NHibernateUtil.Int32;
4. 解决问题:
把AddScalar方法的参数里一个属性改了一下:
ISession session = DAORepository.Instrance.DbSession;
string queryString = "select CreateTime,Address,Password, (case when EmailType = 0 then 'Gmail' when EmailType = 1 then 'Yahoo' when EmailType = 2 then 'Hotmail' else 'Other' end) as EmailType from MailInfo where status=0 Order by CreateTime desc";
ISQLQuery query = session.CreateSQLQuery(queryString).AddScalar("CreateTime",NHibernateUtil.String)
.AddScalar("Address",NHibernateUtil.String)
.AddScalar("Password",NHibernateUtil.String)
.AddScalar("EmailType",NHibernateUtil.String);
IList lst = query.List();
ISession session = DAORepository.Instrance.DbSession;
string queryString = "select CreateTime,Address,Password, (case when EmailType = 0 then 'Gmail' when EmailType = 1 then 'Yahoo' when EmailType = 2 then 'Hotmail' else 'Other' end) as EmailType from MailInfo where status=0 Order by CreateTime desc";
ISQLQuery query = session.CreateSQLQuery(queryString).AddScalar("CreateTime",NHibernateUtil.String)
.AddScalar("Address",NHibernateUtil.String)
.AddScalar("Password",NHibernateUtil.String)
.AddScalar("EmailType",NHibernateUtil.String);
IList lst = query.List();
注意:这里我将EmailType的类型映射改为了NHibernateUtil.String,实际上是与返回结果的EmailType值类型保持一致就OK了。
相关文章推荐
- Hibernate 使用createSQLQuery查询时,缓存问题
- 对原生SQL查询执行的控制是通过SQLQuery接口进行的,通过执行Session.createSQLQuery()
- jpa或bernate使用原生sql进行关联查询org.hibernate.hql.internal.ast.QuerySyntaxException: Path expected for join
- 使用NHibernate CreateSQLQuery,需指定类型
- 使用Query进行HQL语句查询和SQL语句查询
- 使用hibernate的this.getSession().createSQLQuery(sql).list();方法查询数据时出现查到的数据和想象的不一致,很是郁闷,诡异
- Hibernate中使用原生的sql语句进行查询操作
- Spring-JDBC:在使用JdbcTemplate进行条件查询时没有返回数据,但是sql直接在数据库中执行是有数据返回的。
- 使用T-SQL进行活动目录查询
- Hibernate使用二级缓存时,createSQLQuery需要注意的问题
- Excel 中使用SQL 语句查询数据(七)-----用LIKE 运算符进行模糊匹配查询
- CreateSqlQuery 查询结果类型转换异常
- Hibernate的createSQLQuery 查询数据库类型为char的字段时要注意
- Hibernate使用sql进行查询的问题
- 使用SQL进行递归查询
- 使用 getSession().createSQLQuery(hql)后出现的奇怪BUG
- 使用sql进行查询重复数据
- Oracle使用SQL语句进行递归查询
- 使用hibernate3的createSQLQuery遇到的问题
- [Beego模型] 四、使用SQL语句进行查询