Real Time Android Development
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How to use SQLite Database in Android

Android provides several ways to store user and app data. SQLite is one way of storing user data. SQLite is a very light weight database which comes with Android OS. In this tutorial I’ll be discussing how to write classes to handle all SQLite operations.

In this tutorial I am taking an example of storing user contacts in SQLite database. I am using a table called Contacts to store user contacts. This table contains three columns id (INT), name (TEXT), phone_number(TEXT).

Contacts Table Structure

Sqlite contacts table

Writing Contact Class

Before you go further you need to write your Contact class with all getter and setter methods to maintain single contact as an object.

Contact.java
package in.co.makeiton.androidsqlite;
 
public class Contact {
      
     //private variables
     int _id;
     String _name;
     String _phone_number;
      
     // Empty constructor
     public Contact(){
          
     }
     // constructor
     public Contact( int id, String name, String _phone_number){
         this ._id = id;
         this ._name = name;
         this ._phone_number = _phone_number;
     }
      
     // constructor
     public Contact(String name, String _phone_number){
         this ._name = name;
         this ._phone_number = _phone_number;
     }
     // getting ID
     public int getID(){
         return this ._id;
     }
      
     // setting id
     public void setID( int id){
         this ._id = id;
     }
      
     // getting name
     public String getName(){
         return this ._name;
     }
      
     // setting name
     public void setName(String name){
         this ._name = name;
     }
      
     // getting phone number
     public String getPhoneNumber(){
         return this ._phone_number;
     }
      
     // setting phone number
     public void setPhoneNumber(String phone_number){
         this ._phone_number = phone_number;
     }
}

Writing SQLite Database Handler Class

  We need to write our own class to handle all database CRUD(Create, Read, Update and Delete) operations.

1. Create a new project by going to File ⇒ New Android Project.
2. Once the project is created, create a new class in your project src directory and name it as DatabaseHandler.java ( Right Click on src/package ⇒ New ⇒ Class)
3. Now extend your DatabaseHandler.java class from SQLiteOpenHelper.



public class DatabaseHandler extends SQLiteOpenHelper {

4. After extending your class from SQLiteOpenHelper you need to override two methods onCreate() and onUpgrage()
onCreate() – These is where we need to write create table statements. This is called when database is created.
onUpgrade() – This method is called when database is upgraded like modifying the table structure, adding constraints to database etc.,

public class DatabaseHandler extends SQLiteOpenHelper {
 
     // All Static variables
     // Database Version
     private static final int DATABASE_VERSION = 1 ;
 
     // Database Name
     private static final String DATABASE_NAME = "contactsManager" ;
 
     // Contacts table name
     private static final String TABLE_CONTACTS = "contacts" ;
 
     // Contacts Table Columns names
     private static final String KEY_ID = "id" ;
     private static final String KEY_NAME = "name" ;
     private static final String KEY_PH_NO = "phone_number" ;
 
     public DatabaseHandler(Context context) {
         super (context, DATABASE_NAME, null , DATABASE_VERSION);
     }
 
     // Creating Tables
     @Override
     public void onCreate(SQLiteDatabase db) {
         String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_CONTACTS + "("
                 + KEY_ID + " INTEGER PRIMARY KEY," + KEY_NAME + " TEXT,"
                 + KEY_PH_NO + " TEXT" + ")" ;
         db.execSQL(CREATE_CONTACTS_TABLE);
     }
 
     // Upgrading database
     @Override
     public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
         // Drop older table if existed
         db.execSQL( "DROP TABLE IF EXISTS " + TABLE_CONTACTS);
 
         // Create tables again
         onCreate(db);
     }

⇒All CRUD Operations (Create, Read, Update and Delete)

Now we need to write methods for handling all database read and write operations. Here we are implementing following methods for our contacts table.

// Adding new contact
public void addContact(Contact contact) {}
 
// Getting single contact
public Contact getContact( int id) {}
 
// Getting All Contacts
public List<Contact> getAllContacts() {}
 
// Getting contacts Count
public int getContactsCount() {}
// Updating single contact
public int updateContact(Contact contact) {}
 
// Deleting single contact
public void deleteContact(Contact contact) {}

⇒Inserting new Record

The addContact() method accepts Contact object as parameter. We need to build ContentValues parameters using Contact object. Once we inserted data in database we need to close the database connection.

addContact()
     // Adding new contact
public void addContact(Contact contact) {
     SQLiteDatabase db = this .getWritableDatabase();
 
     ContentValues values = new ContentValues();
     values.put(KEY_NAME, contact.getName()); // Contact Name
     values.put(KEY_PH_NO, contact.getPhoneNumber()); // Contact Phone Number
 
     // Inserting Row
     db.insert(TABLE_CONTACTS, null , values);
     db.close(); // Closing database connection
}

⇒Reading Row(s)

The following method getContact() will read single contact row. It accepts id as parameter and will return the matched row from the database.

getContact()
     // Getting single contact
public Contact getContact( int id) {
     SQLiteDatabase db = this .getReadableDatabase();
 
     Cursor cursor = db.query(TABLE_CONTACTS, new String[] { KEY_ID,
             KEY_NAME, KEY_PH_NO }, KEY_ID + "=?" ,
             new String[] { String.valueOf(id) }, null , null , null , null );
     if (cursor != null )
         cursor.moveToFirst();
 
     Contact contact = new Contact(Integer.parseInt(cursor.getString( 0 )),
             cursor.getString( 1 ), cursor.getString( 2 ));
     // return contact
     return contact;
}

getAllContacts() will return all contacts from database in array list format of Contact class type. You need to write a for loop to go through each contact.

getAllContacts()
     // Getting All Contacts
  public List<Contact> getAllContacts() {
     List<Contact> contactList = new ArrayList<Contact>();
     // Select All Query
     String selectQuery = "SELECT  * FROM " + TABLE_CONTACTS;
 
     SQLiteDatabase db = this .getWritableDatabase();
     Cursor cursor = db.rawQuery(selectQuery, null );
 
     // looping through all rows and adding to list
     if (cursor.moveToFirst()) {
         do {
             Contact contact = new Contact();
             contact.setID(Integer.parseInt(cursor.getString( 0 )));
             contact.setName(cursor.getString( 1 ));
             contact.setPhoneNumber(cursor.getString( 2 ));
             // Adding contact to list
             contactList.add(contact);
         } while (cursor.moveToNext());
     }
 
     // return contact list
     return contactList;
}

getContactsCount() will return total number of contacts in SQLite database.

getContactsCount()
// Getting contacts Count
     public int getContactsCount() {
         String countQuery = "SELECT  * FROM " + TABLE_CONTACTS;
         SQLiteDatabase db = this .getReadableDatabase();
         Cursor cursor = db.rawQuery(countQuery, null );
         cursor.close();
 
         // return count
         return cursor.getCount();
     }

⇒Updating Record

updateContact() will update single contact in database. This method accepts Contact class object as parameter.

updateContact()
     // Updating single contact
public int updateContact(Contact contact) {
     SQLiteDatabase db = this .getWritableDatabase();
 
     ContentValues values = new ContentValues();
     values.put(KEY_NAME, contact.getName());
     values.put(KEY_PH_NO, contact.getPhoneNumber());
 
     // updating row
     return db.update(TABLE_CONTACTS, values, KEY_ID + " = ?" ,
             new String[] { String.valueOf(contact.getID()) });
}

⇒Deleting Record

deleteContact() will delete single contact from database.

deleteContact()
     // Deleting single contact
public void deleteContact(Contact contact) {
     SQLiteDatabase db = this .getWritableDatabase();
     db.delete(TABLE_CONTACTS, KEY_ID + " = ?" ,
             new String[] { String.valueOf(contact.getID()) });
     db.close();
}

Complete DatabaseHandler.java Code:

DatabaseHandler.java
package in.co.makeiton.androidsqlite;
 
import java.util.ArrayList;
import java.util.List;
 
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
 
public class DatabaseHandler extends SQLiteOpenHelper {
 
     // All Static variables
     // Database Version
     private static final int DATABASE_VERSION = 1 ;
 
     // Database Name
     private static final String DATABASE_NAME = "contactsManager" ;
 
     // Contacts table name
     private static final String TABLE_CONTACTS = "contacts" ;
 
     // Contacts Table Columns names
     private static final String KEY_ID = "id" ;
     private static final String KEY_NAME = "name" ;
     private static final String KEY_PH_NO = "phone_number" ;
 
     public DatabaseHandler(Context context) {
         super (context, DATABASE_NAME, null , DATABASE_VERSION);
     }
 
     // Creating Tables
     @Override
     public void onCreate(SQLiteDatabase db) {
         String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_CONTACTS + "("
                 + KEY_ID + " INTEGER PRIMARY KEY," + KEY_NAME + " TEXT,"
                 + KEY_PH_NO + " TEXT" + ")" ;
         db.execSQL(CREATE_CONTACTS_TABLE);
     }
 
     // Upgrading database
     @Override
     public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
         // Drop older table if existed
         db.execSQL( "DROP TABLE IF EXISTS " + TABLE_CONTACTS);
 
         // Create tables again
         onCreate(db);
     }
 
     /**
      * All CRUD(Create, Read, Update, Delete) Operations
      */
 
     // Adding new contact
     void addContact(Contact contact) {
         SQLiteDatabase db = this .getWritableDatabase();
 
         ContentValues values = new ContentValues();
         values.put(KEY_NAME, contact.getName()); // Contact Name
         values.put(KEY_PH_NO, contact.getPhoneNumber()); // Contact Phone
 
         // Inserting Row
         db.insert(TABLE_CONTACTS, null , values);
         db.close(); // Closing database connection
     }
 
     // Getting single contact
     Contact getContact( int id) {
         SQLiteDatabase db = this .getReadableDatabase();
 
         Cursor cursor = db.query(TABLE_CONTACTS, new String[] { KEY_ID,
                 KEY_NAME, KEY_PH_NO }, KEY_ID + "=?" ,
                 new String[] { String.valueOf(id) }, null , null , null , null );
         if (cursor != null )
             cursor.moveToFirst();
 
         Contact contact = new Contact(Integer.parseInt(cursor.getString( 0 )),
                 cursor.getString( 1 ), cursor.getString( 2 ));
         // return contact
         return contact;
     }
      
     // Getting All Contacts
     public List<Contact> getAllContacts() {
         List<Contact> contactList = new ArrayList<Contact>();
         // Select All Query
         String selectQuery = "SELECT  * FROM " + TABLE_CONTACTS;
 
         SQLiteDatabase db = this .getWritableDatabase();
         Cursor cursor = db.rawQuery(selectQuery, null );
 
         // looping through all rows and adding to list
         if (cursor.moveToFirst()) {
             do {
                 Contact contact = new Contact();
                 contact.setID(Integer.parseInt(cursor.getString( 0 )));
                 contact.setName(cursor.getString( 1 ));
                 contact.setPhoneNumber(cursor.getString( 2 ));
                 // Adding contact to list
                 contactList.add(contact);
             } while (cursor.moveToNext());
         }
 
         // return contact list
         return contactList;
     }
 
     // Updating single contact
     public int updateContact(Contact contact) {
         SQLiteDatabase db = this .getWritableDatabase();
 
         ContentValues values = new ContentValues();
         values.put(KEY_NAME, contact.getName());
         values.put(KEY_PH_NO, contact.getPhoneNumber());
 
         // updating row
         return db.update(TABLE_CONTACTS, values, KEY_ID + " = ?" ,
                 new String[] { String.valueOf(contact.getID()) });
     }
 
     // Deleting single contact
     public void deleteContact(Contact contact) {
         SQLiteDatabase db = this .getWritableDatabase();
         db.delete(TABLE_CONTACTS, KEY_ID + " = ?" ,
                 new String[] { String.valueOf(contact.getID()) });
         db.close();
     }
 
 
     // Getting contacts Count
     public int getContactsCount() {
         String countQuery = "SELECT  * FROM " + TABLE_CONTACTS;
         SQLiteDatabase db = this .getReadableDatabase();
         Cursor cursor = db.rawQuery(countQuery, null );
         cursor.close();
 
         // return count
         return cursor.getCount();
     }
 
}

Usage:

AndroidSQLiteTutorialActivity
package in.co.makeiton.androidsqlite;
 
import java.util.List;
 
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;
 
public class AndroidSQLiteTutorialActivity extends Activity {
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super .onCreate(savedInstanceState);
         setContentView(R.layout.main);
          
         DatabaseHandler db = new DatabaseHandler( this );
          
         /**
          * CRUD Operations
          * */
         // Inserting Contacts
         Log.d( "Insert: " , "Inserting .." );
         db.addContact( new Contact( "Ravi" , "9100000000" ));       
         db.addContact( new Contact( "Srinivas" , "9199999999" ));
         db.addContact( new Contact( "Tommy" , "9522222222" ));
         db.addContact( new Contact( "Karthik" , "9533333333" ));
          
         // Reading all contacts
         Log.d( "Reading: " , "Reading all contacts.." );
         List<Contact> contacts = db.getAllContacts();      
          
         for (Contact cn : contacts) {
             String log = "Id: " +cn.getID()+ " ,Name: " + cn.getName() + " ,Phone: " + cn.getPhoneNumber();
                 // Writing Contacts to log
         Log.d( "Name: " , log);
     }
     }
}

Android Log Cat Report:

I am writing output to Log report. You can see your log report by going to Windows ⇒ Show View ⇒ Other.. ⇒ Android ⇒ Log Cat.

Android Log Cat
Android Log Cat