09.1. Android - Local Database (Sqlite)
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This document provides information about SQLite databases in Android applications. It discusses how SQLite is integrated into the Android runtime, demonstrates basic SQL statements for creating tables, inserting, updating, deleting and selecting records, and shows code examples for executing SQL statements and retrieving data using a Cursor object in an Android app. It also explains how to view the database files on an Android emulator.
09.1. Android - Local Database (Sqlite)
- 1. 09.1. Database Oum Saokosal Master of Engineering in Information Systems, South Korea 855-12-252-752 [email protected]
- 2. SQLite • SQLite is popular light-weight database • For Android, SQLite is "baked into" the Android runtime, so every Android application can create SQLite databases.
- 3. Fundamental of SQL • Create a table: CREATE TABLE IF NOT EXISTS tbl_student ( stu_id INTEGER PRIMARY KEY AUTOINCREMENT, stu_name VARCHAR(50) NULL, stu_add VARCHAR(100) NULL, stu_gpa FLOAT NULL );
- 4. • Insert a record: INSERT INTO tbl_student VALUES ( 80123, 'Sok Visal', 'Phnom Penh', 4.0 );
- 5. • Select a record: SELECT * FROM tbl_student WHERE stu_id=80123 ORDER BY stu_name ASC • View many records: SELECT * FROM tbl_student WHERE stu_name LIKE '%sok%' ORDER BY stu_name DESC
- 6. • Update a record: UPDATE tbl_student SET stu_name='Sok Visal', stu_add='Takeo', stu_gpa=4.0 WHERE stu_id = 80123;
- 7. • Delete a record: DELETE FROM tbl_student WHERE stu_id=80123;
- 8. SQLite Statements • To Create a database: SQLiteDatabase db = openOrCreateDatabase( "database_name", MODE_PRIVATE, null); • To execute a raw SQL statement: db.execSQL("CREATE TABLE tbl_product (pro_id integer, pro_name nvarchar(50));"); • To close a database: db.close();
- 9. • To create a table by executing a raw SQL statement: db.execSQL("CREATE TABLE IF NOT EXISTS tbl_student (stu_id INT PRIMARY KEY AUTOINCREMENT, stu_name VARCHAR(50) NULL, stu_add VARCHAR(100) NULL, stu_gpa FLOAT);");
- 10. • Insert a record: db.execSQL("INSERT INTO tbl_student VALUES (80123, 'Sok Visal', 'Phnom Penh', 4.0);");
- 11. • Update a record: db.execSQL("UPDATE tbl_student SET stu_name='Sok Visal', stu_add='Takeo', stu_gpa=4.0 WHERE stu_id = 80123;");
- 12. • Delete a record: db.execSQL("DELETE FROM tbl_student WHERE stu_id= 80123;");
- 13. Records Retrieval • After you select records using SELECT, you need to display it. In Android, you will use Cursor class to store the records. Cursor result = db.rawQuery("SELECT * FROM tbl_student WHERE stu_id=80123 ORDER BY stu_name ASC", null);
- 14. • Complete code of records retrieval: Cursor result = db.rawQuery("SELECT * FROM tbl_student WHERE stu_id=80123 ORDER BY stu_name ASC", null); result.moveToFirst(); //Must include this while(result.isAfterLast() != true){ int id = result.getInt(0); String name = result.getString(1); String address = result.getString(2); int gpa = result.getFloat(3); //Do something here result.moveToNext(); }
- 15. Where is My Database? • Please note that to see the database folder, you need to run the emulator first. • After created a database, you can find it by going to DDMS -> File Explorer -> Then open the folder: data/data/your.app.package/databases/yourdbname
- 17. How to View My Database? • There is a plugin that allows you to view SQLite file in Eclipse. Below is the url: http://www.tylerfrankenstein.com/user/4/browse-android- emulator-sqlite-database-eclipse • After you download it onto your machine, place it here:
- 18. How to View My Database? Cont.
- 19. Project Assignment • Think of your own favorite project related to a database and intent. And then make it a nice App for Android.
- 20. Go on to the next slide