requery - Java/Android强大的ORM和SQL查询生成器

jopen 6年前


requery一个轻量级但强大的Java/Android的ORM和SQL查询生成器,支持RxJava和Java 8。

Defining entities:

@Entity  abstract class AbstractPerson {        @Key @Generated      int id;        @Index(name = "name_index")              // table specification      String name;        @OneToMany                               // relationships 1:1, 1:many, many to many      Set<Phone> phoneNumbers;        @Converter(EmailToStringConverter.class) // custom type conversion      Email email;        @PostLoad                                // lifecycle callbacks      void afterLoad() {          updatePeopleList();      }        // getter, setters, equals & hashCode automatically generated into  }

or from an interface:

@Entity  public interface Person {        @Key @Generated      int getId();        String getName();        @OneToMany      Set<Phone> getPhoneNumbers();        String getEmail();  }


List<Person> query = data      .select(Person.class)      .where(Person.NAME.lower().like("b%"))      .orderBy(Person.AGE.desc())      .limit(5)      .get().list();

Relationships: rather than collections such as sets, and lists which have to be materialized with all the results, you can use query results directly in side an entity: (sets and lists are supported to)

@Entity  abstract class AbstractPerson {        @Key @Generated      int id;        @ManyToMany      Result<Group> groups;      // equivalent to:      //      // .join(Group_Person.class).on(Group_ID.equal(Group_Person.GROUP_ID))      // .join(Person.class).on(Group_Person.PERSON_ID.equal(Person.ID))      // .where(Person.ID.equal(id))  }

Java 8 streams:      .orderBy(Person.AGE.desc())      .get()      .stream().forEach(System.out::println);

Java 8 optional and time support:

public interface Person {        @Key @Generated      int getId();        String getName();      Optional<String> getEmail();      ZonedDateTime getBirthday();  }

RxJava Observables:

Observable<Person> observable = data      .select(Person.class)      .orderBy(Person.AGE.desc())      .get()      .toObservable();

RxJava observe query on table changes:

Observable<Person> observable = data      .select(Person.class)      .orderBy(Person.AGE.desc())      .get()      .toSelfObservable().subscribe(::updateFromResult);

Optional Read/write separation. If you prefer separating read from writes mark the entity as @ReadOnly and use update statements to modify data instead.

int rows = data.update(Person.class)      .set(Person.ABOUT, "nothing")      .set(Person.AGE, 50)      .where(Person.AGE.equal(100)).get();


  • No Reflection
  • Fast startup
  • Typed query language
  • Table generation
  • Supports JDBC and many popular databases
  • Supports Android (SQLite, RecyclerView, Databinding)
  • RxJava support
  • Blocking and non-blocking API
  • Partial objects/refresh
  • Caching
  • Lifecycle callbacks
  • Custom type converters
  • JPA annotations (however requery is not a JPA provider)

Reflection free

requery uses compile time annotation processing to generate your entity model classes. On Android this means you get about the same performance reading objects from a query as if it was populated using the standard Cursor and ContentValues API.

Type safe query

The compiled classes work with the query API to take advantage of compile time generated attributes. Create type safe queries and avoid hard to maintain, error prone string concatenated queries.


You can define One-to-One, One-to-Many, Many-to-One, and Many-to-Many relations in your models using annotations. Relationships can be navigated in both directions. Of many type relations can be loaded into standard java collection objects or into a more efficient iterable only object. Many-to-Many junction tables can be generated automatically. Additionally the relation model is validated at compile time eliminating runtime errors.


Designed specifically with Android support in mind.

Comparison to similar Android libraries:

Feature requery ORMLite Squidb DBFlow GreenDao
Relational mapping Y Y(1) N Y(1) Y(1)
Inverse relationships Y N N N N
Compile time Y N Y Y Y(2)
JDBC Support Y Y N N N
query language Y N Y(3) Y(3) Y(3)
Table Generation Y Y Y Y Y
JPA annotations Y Y N N N

1) Excludes Many-to-Many 2) Not annotation based 3) Builder only

See requery-android/example for an example Android project using databinding and interface based entities. For more information see the wiki page.

Code generation

Generate entities from Abstract or Interface classes. Use JPA annotations or requery annotations. requery will generate getter/setters, equals() and hashcode() when needed.

Supported Databases

Tested on some of the most popular databases:

  • PostgresSQL (9.1+)
  • MySQL 5.x
  • Oracle 12c+
  • Microsoft SQL Server 2012 or later
  • SQLite (Android or with xerial JDBC driver)
  • Apache Derby 10.11+
  • H2 1.4+
  • HSQLDB 2.3+

JPA Annotations

A subset of the JPA annotations that map onto the requery annotations are supported. See here for more information.

Using it

Currently SNAPSHOT versions are available on

repositories {      jcenter()      maven { url '' }  }    dependencies {      compile 'io.requery:requery:1.0-SNAPSHOT'      compile 'io.requery:requery-android:1.0-SNAPSHOT' // for android      apt 'io.requery:requery-processor:1.0-SNAPSHOT'   // prefer an APT plugin  }

Feedback and suggestions are welcome.

For more information see the wiki page.


Copyright (C) 2016    Licensed under the Apache License, Version 2.0 (the "License");  you may not use this file except in compliance with the License.  You may obtain a copy of the License at    Unless required by applicable law or agreed to in writing, software  distributed under the License is distributed on an "AS IS" BASIS,  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the License for the specific language governing permissions and  limitations under the License.