JAVA Hibernate Query Language

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    Apex T. G. India Pvt. Ltd

    Hibernate QueryLanguage

    http://apextgi.in/http://apextgi.in/
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    HQL Hibernate Framework comes with a powerf!

    ob"ect#oriented $er% !an&a&e ' Hibernate Qer%

    Lan&a&e)HQL*.

    It+s ver% simi!ar to ,QL except that we se -b"ects

    instead of tab!e names that makes it more c!ose

    to ob"ect oriented pro&rammin&.

    Hibernate $er% !an&a&e is case#insensitive

    except for "ava c!ass and variab!e names.

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    HQL Hibernate Qer% Lan&a&e is sed to execte

    $eries a&ainst database.

    Hibernate atomatica!!% &enerates the s$! $er%

    and execte it a&ainst nder!%in& database if HQL

    is sed in the app!ication.

    HQL is based on the re!ationa! ob"ect mode!s and

    makes the ,QL ob"ect oriented.

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    HQL Hibernate Qer% Lan&a&e is extreme!% powerf!

    and it spports Po!%morphism Associations /ch

    !ess verbose than ,QL.

    0eason To se

    F!! spport for re!ationa! operations HQL a!!ows

    representin& ,QL $eries in the form of ob"ects.

    Hibernate Qer% Lan&a&e ses 2!asses and

    properties instead of tab!es and co!mns.

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    HQL 0etrn res!t as -b"ect The HQL $eries retrn the

    $er% res!t)s* in the form of ob"ect)s* which is

    eas% to se. This e!iminates the need of creatin&

    the ob"ect and pop!ate the data from res!t set.

    Po!%morphic Qeries HQL f!!% spports

    po!%morphic $eries. Po!%morphic $eries res!ts

    the $er% res!ts a!on& with a!! the chi!d ob"ects if

    an%.

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    HQL 3as% to Learn Hibernate Qeries are eas% to !earn

    and it can be easi!% imp!emented in the

    app!ications.

    ,pport for Advance featres HQL contains man%

    advance featres sch as pa&ination fetch "oin

    with d%namic pro4!in& Inner5oter5f!! "oins

    2artesian prodcts. It a!so spports Pro"ection

    A&&re&ation )max av&* and &ropin& -rderin&

    ,b $eries and ,QL fnction ca!!s.

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    HQL 6atabase independent Qeries written in HQL are

    database independent )If database spports the

    nder!%in& featre*.

    7nderstandin& HQL ,%ntax

    Hibernate Qer% Lan&a&e ma% consist of

    fo!!owin& e!ements

    2!ases

    A&&re&ate fnctions

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    HQL ,b $eries

    2!ases in HQL

    from

    se!ect

    where

    order b%

    &rop b%

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    HQLA&&re&ate fnctions are

    av&)...* sm)...* min)...* max)...*

    cont)8*

    cont)...* cont)distinct ...* cont)a!!...*

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    HQL 2!ase

    From 2!ase

    It is same as se!ect c!ase in ,QL +from

    3mp!o%ee+ is same as +se!ect 8 from 3mp!o%ee+. 9e

    can a!so create a!ias sch as from 3mp!o%ee

    emp or from 3mp!o%ee as emp.For 3xamp!e

    session.createQer%):from3mp!o%ee:*;

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    HQL

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    HQL

    A&&re&ate Fnctions

    HQL spports common!% sed a&&re&ate fnctions

    sch as cont)8* cont)distinct x* min)* max)*

    av&)* and sm)* etc .For 3xamp!e

    session.createQer%):se!ect sm)sa!* from ,tdent:*;

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    HQL

    3xpressions

    HQL spports arithmetic expressions )> # 8 5*

    binar% comparison operators )? @? ? @ B?

    !ike* !o&ica! operations )and or not* etc. . For

    3xamp!e session.createQer%):se!ect sa! from ,tdent whereid?1:*;

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    HQL

    HQL a!so spports order b% and &rop b% c!ases.

    HQL a!so spports sb#$eries "st !ike ,QL

    $eries.

    HQL spports 66L 6/L and exectin& store

    procedres too.

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    2ontact s

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