Native sql (本地sql)在Hibernate中
Native sql 本地sql在Hibernate中
http://www.hibernate.org/hib_docs/v3/reference/en/html/querysql.html
使用SQLQuery
1. 标量查询scalar query
如
sess.CreateSQLQuery("SELECT * FROM CATS")
.AddScalar("ID", NHibernateUtil.Int64)
.AddScalar("NAME", NHibernateUtil.String)
.AddScalar("BIRTHDATE", NHibernateUtil.Date)
返回List的Object[]，每个Object有上述三个字段组成。
2. Entity query
如
sess.CreateSQLQuery("SELECT * FROM CATS").AddEntity(typeof(Cat));
sess.CreateSQLQuery("SELECT ID, NAME, BIRTHDATE FROM CATS").AddEntity(typeof(Cat));
返回List的Cat[]。
3. 处理association和collections
如
sess.CreateSQLQuery("SELECT c.*, m.* FROM CATS c, CATS m WHERE c.MOTHER_ID = c.ID")
.AddEntity("cat", typeof(Cat))
.AddEntity("mother", typeof(Cat))
每行将返回两个Cat对象：一个Cat，一个Cat的mother。
但是上面的代码会造成列名的冲突问题。
因此：
sess.CreateSQLQuery("SELECT {cat.*}, {mother.*} FROM CATS c, CATS m WHERE c.MOTHER_ID = c.ID")
.AddEntity("cat", typeof(Cat))
.AddEntity("mother", typeof(Cat))
4. alias和property引用
| Description
|
Syntax
|
Example
|
| A simple property |
{[aliasname].[propertyname]} |
A_NAME as {item.Name} |
| A composite property |
{[aliasname].[componentname].[propertyname]} |
CURRENCY as {item.Amount.Currency}, VALUE as {item.Amount.Value} |
| Discriminator of an entity |
{[aliasname].class} |
DISC as {item.class} |
| All properties of an entity |
{[aliasname].*} |
{item.*} |
| A collection key |
{[aliasname].key} |
ORGID as {coll.key} |
| The id of an collection |
{[aliasname].id} |
EMPID as {coll.id} |
| The element of an collection |
{[aliasname].element} |
XID as {coll.element} |
| property of the element in the collection |
{[aliasname].element.[propertyname]} |
NAME as {coll.element.Name} |
| All properties of the element in the collection |
{[aliasname].element.*} |
{coll.element.*} |
| All properties of the the collection |
{[aliasname].*} |
{coll.*} |
5. 得到non-managed entities
处理继承
native sql查询的实体是一个继承结构中的一部分的话，就必须包括进来其基类和子类的属性。
6. 参数
Query query = sess.CreateSQLQuery("SELECT * FROM CATS WHERE NAME like ?").AddEntity(typeof(Cat));
IList pusList = query.SetString(0, "Pus%").List();
query = sess.createSQLQuery("SELECT * FROM CATS WHERE NAME like :name").AddEntity(typeof(Cat));
IList pusList = query.SetString("name", "Pus%").List();
Named sql queries
1. Scalar query
SELECT p.NAME AS name,
p.AGE AS age,
FROM PERSON p WHERE p.NAME LIKE 'Hiber%'
2. Entity query
SELECT person.NAME AS {person.Name},
person.AGE AS {person.Age},
person.SEX AS {person.Sex}
FROM PERSON person
WHERE person.NAME LIKE :namePattern
IList people = sess.GetNamedQuery("persons")
.SetString("namePattern", namePattern)
.SetMaxResults(50)
.List();
return的含义：这个查询返回一个alias的实体。
3. return-join和load-collection
<return alias="person" class="eg.Person"/>
<return-join alias="address" property="person.MailingAddress"/>
SELECT person.NAME AS {person.Name},
person.AGE AS {person.Age},
person.SEX AS {person.Sex},
adddress.STREET AS {address.Street},
adddress.CITY AS {address.City},
adddress.STATE AS {address.State},
adddress.ZIP AS {address.Zip}
FROM PERSON person
JOIN ADDRESS adddress
ON person.ID = address.PERSON_ID AND address.TYPE='MAILING'
WHERE person.NAME LIKE :namePattern
return-join和load-collection都可以参照第一部分中的assocation和collection。
4. 利用resultset扩展关于结果集映射（参考上面的return和return-join）的信息
SELECT person.NAME AS {person.Name},
person.AGE AS {person.Age},
person.SEX AS {person.Sex},
adddress.STREET AS {address.Street},
adddress.CITY AS {address.City},
adddress.STATE AS {address.State},
adddress.ZIP AS {address.Zip}
FROM PERSON person
JOIN ADDRESS adddress
ON person.ID = address.PERSON_ID AND address.TYPE='MAILING'
WHERE person.NAME LIKE :namePattern
用程序的方式处理上面的配置信息：
IList cats = sess.CreateSQLQuery(
"select {cat.*}, {kitten.*} from cats cat, cats kitten where kitten.mother = cat.id"
)
.SetResultSetMapping("catAndKitten")
.List();
5. 显示指定结果集中的column的显示名字（return-property）
SELECT person.NAME AS myName,
person.AGE AS myAge,
person.SEX AS mySex,
FROM PERSON person WHERE person.NAME LIKE :name
将多column映射为一个名字
SELECT EMPLOYEE AS {emp.Employee}, EMPLOYER AS {emp.Employer},
STARTDATE AS {emp.StartDate}, ENDDATE AS {emp.EndDate},
REGIONCODE as {emp.RegionCode}, EID AS {emp.Id}, VALUE, CURRENCY
FROM EMPLOYMENT
WHERE EMPLOYER = :id AND ENDDATE IS NULL
ORDER BY STARTDATE ASC
6. stored procedures
exec selectAllEmployments
stored procedures的使用有一些限制，如果不遵守，就不能在Hibernate中使用stored procedures，而只能用session.connection()。限制根据db的不同而不同，因为不同的db中stored procedures有差别。
Stored procedure queries can't be paged with setFirstResult()/setMaxResults().
Recommended call form is standard SQL92: { ? = call functionName(
For Oracle the following rules apply:
· A function must return a result set. The first parameter of a procedure must be an OUT that returns a result set. This is done by using a SYS_REFCURSOR type in Oracle 9 or 10. In Oracle you need to define a REF CURSOR type, see Oracle literature.
For Sybase or MS SQL server the following rules apply:
· The procedure must return a result set. Note that since these servers can/will return multiple result sets and update counts, Hibernate will iterate the results and take the first result that is a result set as its return value. Everything else will be discarded.
· If you can enable SET NOCOUNT ON in your procedure it will probably be more efficient, but this is not a requirement.