A Simple DBFlow Tutorial

DBFlow is a simple and powerful Android ORM database library with annotation processing.

Install and configure

Add classpath ‘com.neenbedankt.gradle.plugins:android-apt:1.8’ to dependencies of buildscript and maven { url “https://jitpack.io” } to reposities of allscripts in your root’s gradle.build. Here is how it looks after adding these lines:

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
repositories {
jcenter()
}
dependencies {
classpath 'com.android.tools.build:gradle:2.1.3'
//add the following line for DBFLow
classpath 'com.neenbedankt.gradle.plugins:android-apt:1.8'
// NOTE: Do not place your application dependencies here; they belong
// in the individual module build.gradle files
}
}

allprojects {
repositories {
jcenter()
//add the following line for DBFLow
maven { url "https://jitpack.io" }
}
}

task clean(type: Delete) {
delete rootProject.buildDir
}

We will apply android-apt plugin and add DBFlow dependency in app’s gradle.build.

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

android {
compileSdkVersion 24
buildToolsVersion "24.0.0"

defaultConfig {
applicationId "com.androidnames.dbflowexample"
minSdkVersion 16
targetSdkVersion 24
versionCode 1
versionName "1.0"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}

}

def dbflow_version = "3.1.1"

dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
testCompile 'junit:junit:4.12'
compile 'com.android.support:appcompat-v7:24.2.0'

apt "com.github.Raizlabs.DBFlow:dbflow-processor:${dbflow_version}"
// use kapt for kotlin apt
compile "com.github.Raizlabs.DBFlow:dbflow-core:${dbflow_version}"
compile "com.github.Raizlabs.DBFlow:dbflow:${dbflow_version}"
// kotlin extensions
compile "com.github.Raizlabs.DBFlow:dbflow-kotlinextensions:${dbflow_version}"

}

To initialize the database, add FlowManager.init(new FlowConfig.Builder(this).build()); to MainActivity’s onCreate method.

FlowManager.init(new FlowConfig.Builder(this).build());

Create a database

Annotation @Database is used to declare a database. It will contain both database’s name and version. Version is often set as 1 when starting a project. The number is increased when there are changes in the schema. Create a class with the same name:

public class CompanyDatabase {

public static final String NAME = "CompanyDatabase";

public static final int VERSION = 1;
}

Create tables

The Java object needs to extend from BaseModel for DBFlow to recognize it as a model. Annotation @Table is used to define a class as a model. Let’s create 2 models, Department and Employee.

@Table(database = CompanyDatabase.class)
public class Department extends BaseModel{
@Column
@PrimaryKey
private int id;

@Column
private String name;

public int getId() {
return id;
}

public void setId(int id) {
this.id = id;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}
}

@Table(database = CompanyDatabase.class)
public class Employee extends BaseModel {
@Column
@PrimaryKey
private int id;

@Column
private String name;

@Column
private int age;

@Column
@ForeignKey(saveForeignKeyModel = false)
private Department department;

public int getId() {
return id;
}

public void setId(int id) {
this.id = id;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public int getAge() {
return age;
}

public void setAge(int age) {
this.age = age;
}

public Department getDepartment() {
return department;
}

public void setDepartment(Department department) {
this.department = department;
}
}

CRUD operations

Create and update objects
save() method is used to add a row to a table. If a row already existed, it updates the database with the object’s new values.

Department department = new Department();
department.setName("Human Resources");
department.save();

Read objects
Class with suffix “_Table” is generated automatically. It contains convenience Properties that provide easy SQL operations.

]List<Department> departments = new Select().from(Department.class).queryList();
List<Employee> employees = new Select()
.from(Employee.class)
.where(Employee_Table.department_id.is(1))
.and((Employee_Table.age.greaterThan(20)))
.queryList();

Delete objects
It is quite simple, just call the delete() method.

employee.delete();