A light but powerful ORM and SQL query generator for Java/Android with RxJava and Java 8 support.

Examples

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 Person.java
}

or from an interface:

@Entity
public interface Person {

    @Key @Generated
    int getId();

    String getName();

    @OneToMany
    Set<Phone> getPhoneNumbers();

    String getEmail();
}

Queries:

Result<Person> query = data
    .select(Person.class)
    .where(Person.NAME.lower().like("b%")).and(Person.AGE.gt(20))
    .orderBy(Person.AGE.desc())
    .limit(5)
    .get();

Relationships: represent relations more efficiently with Java 8 Streams, RxJava Observables or plain iterables. (sets and lists are supported to)

@Entity
abstract class AbstractPerson {

    @Key @Generated
    int id;

    @ManyToMany
    Result<Group> groups;
    // equivalent to:
    // data.select(Group.class)
    // .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:

data.select(Person.class)
    .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);

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();

Features

• 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
• Compile time entity validation
• 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.

Relationships

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 Result type. From a Result easily create a Stream, RxJava Observable, Iterator, List or Map.

Many-to-Many junction tables can be generated automatically. Additionally the relation model is validated at compile time eliminating runtime errors.

Android

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	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 not DSL

See requery-android/example for an example Android project using databinding and interface based entities. For more information see the Android 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 the 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 http://oss.jfrog.org.

repositories {
    jcenter()
    maven { url 'http://oss.jfrog.org/artifactory/oss-snapshot-local' }
}

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
}

For Android, in order to process the apt dependency, also include the android-apt plugin:

buildscript {
    dependencies {
        classpath 'com.neenbedankt.gradle.plugins:android-apt:1.8'
    }
}

apply plugin: 'com.neenbedankt.android-apt'

For more information see the wiki. Feedback and suggestions are welcome.

License

Copyright (C) 2016 requery.io

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

http://www.apache.org/licenses/LICENSE-2.0

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.