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You can also express queries in the native SQL dialect of your database. This is useful if you want to utilize database-specific features such as query hints or the CONNECT
keyword in Oracle. It also provides a clean migration path from a direct SQL/JDBC based application to Hibernate.
Hibernate3 allows you to specify handwritten SQL, including stored procedures, for all create, update, delete, and load operations.
Execution of native SQL queries is controlled via the SQLQuery
interface, which is obtained by calling Session.createSQLQuery()
. The following sections describe how to use this API for querying.
最も基本的なSQLクエリはスカラー(値)のリストを得ることです。
sess.createSQLQuery("SELECT * FROM CATS").list(); sess.createSQLQuery("SELECT ID, NAME, BIRTHDATE FROM CATS").list();
These will return a List of Object arrays (Object[]) with scalar values for each column in the CATS table. Hibernate will use ResultSetMetadata to deduce the actual order and types of the returned scalar values.
To avoid the overhead of using ResultSetMetadata
, or simply to be more explicit in what is returned, one can use addScalar()
:
sess.createSQLQuery("SELECT * FROM CATS") .addScalar("ID", Hibernate.LONG) .addScalar("NAME", Hibernate.STRING) .addScalar("BIRTHDATE", Hibernate.DATE)
このクエリで指定されているものを下記に示します。
SQLクエリ文字列
返されるカラムと型
This will return Object arrays, but now it will not use ResultSetMetadata
but will instead explicitly get the ID, NAME and BIRTHDATE column as respectively a Long, String and a Short from the underlying resultset. This also means that only these three columns will be returned, even though the query is using *
and could return more than the three listed columns.
スカラーの型情報を省くこともできます。
sess.createSQLQuery("SELECT * FROM CATS") .addScalar("ID", Hibernate.LONG) .addScalar("NAME") .addScalar("BIRTHDATE")
This is essentially the same query as before, but now ResultSetMetaData
is used to determine the type of NAME and BIRTHDATE, where as the type of ID is explicitly specified.
How the java.sql.Types returned from ResultSetMetaData is mapped to Hibernate types is controlled by the Dialect. If a specific type is not mapped, or does not result in the expected type, it is possible to customize it via calls to registerHibernateType
in the Dialect.
ここまでのクエリは、すべてスカラー値を返すものでした。 基本的に、リザルトセットから「未加工」の値を返します。 以降では、addEntity()
により、ネイティブSQLクエリから エンティティオブジェクトを取得する方法を示します。
sess.createSQLQuery("SELECT * FROM CATS").addEntity(Cat.class); sess.createSQLQuery("SELECT ID, NAME, BIRTHDATE FROM CATS").addEntity(Cat.class);
このクエリで指定されているものを下記に示します。
SQLクエリ文字列
クエリが返すエンティティとSQLテーブルの別名
CatがID, NAME, BIRTHDATEのカラムを使ってクラスにマッピングされる場合、 上記のクエリはどちらも、要素がCatエンティティであるリストを返します。
エンティティを別のエンティティに 多対一
でマッピングしている場合は、 ネイティブクエリを実行する際に、この別のエンティティを返すことも要求します。 さもなければ、データベース固有の「column not found(カラムが見つかりません)」エラーが発生します。 * 表記を使用した際は、追加のカラムが自動的に返されますが、 次の例のように、Dog
に 多対一
であることを 明示することを私たちは好みます。
sess.createSQLQuery("SELECT ID, NAME, BIRTHDATE, DOG_ID FROM CATS").addEntity(Cat.class);
これにより cat.getDog() が正しく機能します。
プロキシを初期化するための余分な処理を避けるため、 Dog
の中で即時結合できます。 これは addJoin()
メソッドにより行います。 関連もしくはコレクションに結合できます。
sess.createSQLQuery("SELECT c.ID, NAME, BIRTHDATE, DOG_ID, D_ID, D_NAME FROM CATS c, DOGS d WHERE c.DOG_ID = d.D_ID") .addEntity("cat", Cat.class) .addJoin("cat.dog");
In this example, the returned Cat
's will have their dog
property fully initialized without any extra roundtrip to the database. Notice that you added an alias name ("cat") to be able to specify the target property path of the join. It is possible to do the same eager joining for collections, e.g. if the Cat
had a one-to-many to Dog
instead.
sess.createSQLQuery("SELECT ID, NAME, BIRTHDATE, D_ID, D_NAME, CAT_ID FROM CATS c, DOGS d WHERE c.ID = d.CAT_ID") .addEntity("cat", Cat.class) .addJoin("cat.dogs");
At this stage you are reaching the limits of what is possible with native queries, without starting to enhance the sql queries to make them usable in Hibernate. Problems can arise when returning multiple entities of the same type or when the default alias/column names are not enough.
Until now, the result set column names are assumed to be the same as the column names specified in the mapping document. This can be problematic for SQL queries that join multiple tables, since the same column names can appear in more than one table.
下記のような(失敗しそうな)クエリでは、 カラム別名インジェクション(column alias injection)が必要です。
sess.createSQLQuery("SELECT c.*, m.* FROM CATS c, CATS m WHERE c.MOTHER_ID = c.ID") .addEntity("cat", Cat.class) .addEntity("mother", Cat.class)
The query was intended to return two Cat instances per row: a cat and its mother. The query will, however, fail because there is a conflict of names; the instances are mapped to the same column names. Also, on some databases the returned column aliases will most likely be on the form "c.ID", "c.NAME", etc. which are not equal to the columns specified in the mappings ("ID" and "NAME").
下記の形式は、カラム名が重複しても大丈夫です。
sess.createSQLQuery("SELECT {cat.*}, {mother.*} FROM CATS c, CATS m WHERE c.MOTHER_ID = c.ID") .addEntity("cat", Cat.class) .addEntity("mother", Cat.class)
このクエリで指定されているものを下記に示します。
SQLクエリ文字列 (Hibernateがカラムの別名を挿入するためのプレースホルダを含む)
クエリによって返されるエンティティ
The {cat.*} and {mother.*} notation used above is a shorthand for "all properties". Alternatively, you can list the columns explicitly, but even in this case Hibernate injects the SQL column aliases for each property. The placeholder for a column alias is just the property name qualified by the table alias. In the following example, you retrieve Cats and their mothers from a different table (cat_log) to the one declared in the mapping metadata. You can even use the property aliases in the where clause.
String sql = "SELECT ID as {c.id}, NAME as {c.name}, " + "BIRTHDATE as {c.birthDate}, MOTHER_ID as {c.mother}, {mother.*} " + "FROM CAT_LOG c, CAT_LOG m WHERE {c.mother} = c.ID"; List loggedCats = sess.createSQLQuery(sql) .addEntity("cat", Cat.class) .addEntity("mother", Cat.class).list()
In most cases the above alias injection is needed. For queries relating to more complex mappings, like composite properties, inheritance discriminators, collections etc., you can use specific aliases that allow Hibernate to inject the proper aliases.
The following table shows the different ways you can use the alias injection. Please note that the alias names in the result are simply examples; each alias will have a unique and probably different name when used.
表 16.1. 別名に挿入する名前
説明 | 構文 | 例 |
---|---|---|
単純なプロパティ | {[aliasname].[propertyname]} | A_NAME as {item.name} |
複合プロパティ | {[aliasname].[componentname].[propertyname]} | CURRENCY as {item.amount.currency}, VALUE as {item.amount.value} |
エンティティのクラスを識別する値 | {[aliasname].class} | DISC as {item.class} |
エンティティの全プロパティ | {[aliasname].*} | {item.*} |
コレクションのキー | {[aliasname].key} | ORGID as {coll.key} |
コレクションのID | {[aliasname].id} | EMPID as {coll.id} |
コレクションの要素 | {[aliasname].element} | XID as {coll.element} |
property of the element in the collection | {[aliasname].element.[propertyname]} | NAME as {coll.element.name} |
コレクションの要素の全プロパティ | {[aliasname].element.*} | {coll.element.*} |
コレクションの全プロパティ | {[aliasname].*} | {coll.*} |
It is possible to apply a ResultTransformer to native SQL queries, allowing it to return non-managed entities.
sess.createSQLQuery("SELECT NAME, BIRTHDATE FROM CATS") .setResultTransformer(Transformers.aliasToBean(CatDTO.class))
このクエリで指定されているものを下記に示します。
SQLクエリ文字列
結果を変換したもの
上記のクエリは、インスタンス化し、NAME と BIRTHDATE の値を 対応するプロパティもしくはフィールドに挿入した CatDTO
のリストを返します。
Native SQL queries which query for entities that are mapped as part of an inheritance must include all properties for the baseclass and all its subclasses.
Native SQL queries support positional as well as named parameters:
Query query = sess.createSQLQuery("SELECT * FROM CATS WHERE NAME like ?").addEntity(Cat.class); List pusList = query.setString(0, "Pus%").list(); query = sess.createSQLQuery("SELECT * FROM CATS WHERE NAME like :name").addEntity(Cat.class); List pusList = query.setString("name", "Pus%").list();
Named SQL queries can be defined in the mapping document and called in exactly the same way as a named HQL query. In this case, you do not need to call addEntity()
.
<sql-query name="persons"> <return alias="person" class="eg.Person"/> SELECT person.NAME AS {person.name}, person.AGE AS {person.age}, person.SEX AS {person.sex} FROM PERSON person WHERE person.NAME LIKE :namePattern </sql-query>
List people = sess.getNamedQuery("persons") .setString("namePattern", namePattern) .setMaxResults(50) .list();
The <return-join>
element is use to join associations and the <load-collection>
element is used to define queries which initialize collections,
<sql-query name="personsWith"> <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}, address.STREET AS {address.street}, address.CITY AS {address.city}, address.STATE AS {address.state}, address.ZIP AS {address.zip} FROM PERSON person JOIN ADDRESS address ON person.ID = address.PERSON_ID AND address.TYPE='MAILING' WHERE person.NAME LIKE :namePattern </sql-query>
名前付きSQLクエリはスカラ値を返すこともできます。 <return-scalar>
要素を使って、 列の別名とHibernateの型を宣言しなければなりません。
<sql-query name="mySqlQuery"> <return-scalar column="name" type="string"/> <return-scalar column="age" type="long"/> SELECT p.NAME AS name, p.AGE AS age, FROM PERSON p WHERE p.NAME LIKE 'Hiber%' </sql-query>
You can externalize the resultset mapping information in a <resultset>
element which will allow you to either reuse them across several named queries or through the setResultSetMapping()
API.
<resultset name="personAddress"> <return alias="person" class="eg.Person"/> <return-join alias="address" property="person.mailingAddress"/> </resultset> <sql-query name="personsWith" resultset-ref="personAddress"> SELECT person.NAME AS {person.name}, person.AGE AS {person.age}, person.SEX AS {person.sex}, address.STREET AS {address.street}, address.CITY AS {address.city}, address.STATE AS {address.state}, address.ZIP AS {address.zip} FROM PERSON person JOIN ADDRESS address ON person.ID = address.PERSON_ID AND address.TYPE='MAILING' WHERE person.NAME LIKE :namePattern </sql-query>
You can, alternatively, use the resultset mapping information in your hbm files directly in java code.
List cats = sess.createSQLQuery( "select {cat.*}, {kitten.*} from cats cat, cats kitten where kitten.mother = cat.id" ) .setResultSetMapping("catAndKitten") .list();
You can explicitly tell Hibernate what column aliases to use with <return-property>
, instead of using the {}
-syntax to let Hibernate inject its own aliases.For example:
<sql-query name="mySqlQuery"> <return alias="person" class="eg.Person"> <return-property name="name" column="myName"/> <return-property name="age" column="myAge"/> <return-property name="sex" column="mySex"/> </return> SELECT person.NAME AS myName, person.AGE AS myAge, person.SEX AS mySex, FROM PERSON person WHERE person.NAME LIKE :name </sql-query>
<return-property>
also works with multiple columns. This solves a limitation with the {}
-syntax which cannot allow fine grained control of multi-column properties.
<sql-query name="organizationCurrentEmployments"> <return alias="emp" class="Employment"> <return-property name="salary"> <return-column name="VALUE"/> <return-column name="CURRENCY"/> </return-property> <return-property name="endDate" column="myEndDate"/> </return> 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 </sql-query>
In this example <return-property>
was used in combination with the {}
-syntax for injection. This allows users to choose how they want to refer column and properties.
マッピングに discriminator が含まれている場合、 discriminator の列を指定するために、<return-discriminator> を使わなければなりません。
Hibernate3 provides support for queries via stored procedures and functions. Most of the following documentation is equivalent for both. The stored procedure/function must return a resultset as the first out-parameter to be able to work with Hibernate. An example of such a stored function in Oracle 9 and higher is as follows:
CREATE OR REPLACE FUNCTION selectAllEmployments RETURN SYS_REFCURSOR AS st_cursor SYS_REFCURSOR; BEGIN OPEN st_cursor FOR SELECT EMPLOYEE, EMPLOYER, STARTDATE, ENDDATE, REGIONCODE, EID, VALUE, CURRENCY FROM EMPLOYMENT; RETURN st_cursor; END;
Hibernateでこのクエリを使うためには、 名前付きクエリでマッピングする必要があります。
<sql-query name="selectAllEmployees_SP" callable="true"> <return alias="emp" class="Employment"> <return-property name="employee" column="EMPLOYEE"/> <return-property name="employer" column="EMPLOYER"/> <return-property name="startDate" column="STARTDATE"/> <return-property name="endDate" column="ENDDATE"/> <return-property name="regionCode" column="REGIONCODE"/> <return-property name="id" column="EID"/> <return-property name="salary"> <return-column name="VALUE"/> <return-column name="CURRENCY"/> </return-property> </return> { ? = call selectAllEmployments() } </sql-query>
Stored procedures currently only return scalars and entities. <return-join>
and <load-collection>
are not supported.
You cannot use stored procedures with Hibernate unless you follow some procedure/function rules. If they do not follow those rules they are not usable with Hibernate. If you still want to use these procedures you have to execute them via session.connection()
. The rules are different for each database, since database vendors have different stored procedure semantics/syntax.
Stored procedure queries cannot be paged with setFirstResult()/setMaxResults()
.
The recommended call form is standard SQL92: { ? = call functionName(<parameters>) }
or { ? = call procedureName(<parameters>}
. Native call syntax is not supported.
Oracleには下記のルールが適用されます。
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 further information.
SybaseとMS SQLサーバーに適用されるルールを下記に示します。
The procedure must return a result set. Note that since these servers can 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.
プロシージャの中で SET NOCOUNT ON
を有効にできれば、 おそらく効率がよくなるでしょう。 しかし、これは必要条件ではありません。
Hibernate3は作成、更新、削除処理のためのカスタムSQL文を使用できます。 クラスとコレクションの永続化機構は、コンフィグレーション時に生成された文字列 (insertsql、deletesql、updatesqlなど)のセットをすでに保持しています。 これらの文字列より、 <sql-insert>
、 <sql-delete>
、 <sql-update>
というマッピングタグが優先されます。
<class name="Person"> <id name="id"> <generator class="increment"/> </id> <property name="name" not-null="true"/> <sql-insert>INSERT INTO PERSON (NAME, ID) VALUES ( UPPER(?), ? )</sql-insert> <sql-update>UPDATE PERSON SET NAME=UPPER(?) WHERE ID=?</sql-update> <sql-delete>DELETE FROM PERSON WHERE ID=?</sql-delete> </class>
The SQL is directly executed in your database, so you can use any dialect you like. This will reduce the portability of your mapping if you use database specific SQL.
callable
属性をセットすれば、 ストアドプロシージャを使用できます。
<class name="Person"> <id name="id"> <generator class="increment"/> </id> <property name="name" not-null="true"/> <sql-insert callable="true">{call createPerson (?, ?)}</sql-insert> <sql-delete callable="true">{? = call deletePerson (?)}</sql-delete> <sql-update callable="true">{? = call updatePerson (?, ?)}</sql-update> </class>
The order of the positional parameters is vital, as they must be in the same sequence as Hibernate expects them.
You can view the expected order by enabling debug logging for the org.hibernate.persister.entity
level. With this level enabled, Hibernate will print out the static SQL that is used to create, update, delete etc. entities. To view the expected sequence, do not include your custom SQL in the mapping files, as this will override the Hibernate generated static SQL.
The stored procedures are in most cases required to return the number of rows inserted, updated and deleted, as Hibernate has some runtime checks for the success of the statement. Hibernate always registers the first statement parameter as a numeric output parameter for the CUD operations:
CREATE OR REPLACE FUNCTION updatePerson (uid IN NUMBER, uname IN VARCHAR2) RETURN NUMBER IS BEGIN update PERSON set NAME = uname, where ID = uid; return SQL%ROWCOUNT; END updatePerson;
You can also declare your own SQL (or HQL) queries for entity loading:
<sql-query name="person"> <return alias="pers" class="Person" lock-mode="upgrade"/> SELECT NAME AS {pers.name}, ID AS {pers.id} FROM PERSON WHERE ID=? FOR UPDATE </sql-query>
This is just a named query declaration, as discussed earlier. You can reference this named query in a class mapping:
<class name="Person"> <id name="id"> <generator class="increment"/> </id> <property name="name" not-null="true"/> <loader query-ref="person"/> </class>
これはストアドプロシージャでさえも動作します。
You can even define a query for collection loading:
<set name="employments" inverse="true"> <key/> <one-to-many class="Employment"/> <loader query-ref="employments"/> </set>
<sql-query name="employments"> <load-collection alias="emp" role="Person.employments"/> SELECT {emp.*} FROM EMPLOYMENT emp WHERE EMPLOYER = :id ORDER BY STARTDATE ASC, EMPLOYEE ASC </sql-query>
You can also define an entity loader that loads a collection by join fetching:
<sql-query name="person"> <return alias="pers" class="Person"/> <return-join alias="emp" property="pers.employments"/> SELECT NAME AS {pers.*}, {emp.*} FROM PERSON pers LEFT OUTER JOIN EMPLOYMENT emp ON pers.ID = emp.PERSON_ID WHERE ID=? </sql-query>
製作著作 © 2004 Red Hat Middleware, LLC.