Lecture 5: Storage: Saving Data Database, Files & Preferences

Lecture 5: Storage: Saving Data
Database, Files & Preferences [1]
Ahsanul Karim
karim.ahsanul@gmail.com
http://droidtraining.wordpress.com
Android Application Development
1. Storage Options
2. Saving Data into a Database
a. Introduction to SQLite
b. SQL Helper Database Creation
c. CRUD [Create Read Update Delete]
3. Using a Pre-populated Database
4. Some optimizations

Saving Data Storage Options
Options to save persistent application data:
[1] Shared Preferences:
Store private primitive data in key-value pairs.
[2] Internal Storage:
Store private data on the device memory.
[3] External Storage:
Store public data on the shared external storage.
[4] SQLite Databases:
Store structured data in a private database.
[5] Network Connection:
Store data on the web with your network server.

Saving Data Today We’ll Discuss...
1. Saving Data into Database
a. Introduction to SQLite
b. SQLiteOpenHelper: Database Creation
c. CRUD [Create Read Update Delete]
2. Using a Pre-populated Database
3. Some optimizations

Saving Data into a Database
Introduction to SQLite
[1]
SQLite is a software library that implements SQL database engine
[1] Self-contained:
Requires very minimal support from external libraries or from the
operating system. (well suited for embedded devices)
[2] Serverless:
No separate server process like most SQL database implementations
(MySql, Oracle etc.). The process that wants to access the database
reads and writes directly from the database files on disk.
[3] Zero-configuration:
Does not need to be "installed". There is no "setup" procedure. There is
no server process that needs to be started, stopped, or configured. No
need for an administrator to create a new database instance or assign
access permissions to users.
[4] Transactional:
All changes and queries appear to be Atomic, Consistent, Isolated, and
Durable (ACID)

Saving Data into a Database
Introduction to SQLite
[2]
Features:
1. Self-contained, Serverless, Zero-configuration and Transactional
2. A complete database is stored in a single cross-platform disk file.
3. Supports terabyte-sized databases and gigabyte-sized strings and
blobs.
4. Small code footprint
5. Faster than popular client/server database engines for most
operations.
6. Simple, easy to use API.
7. Written in ANSI-C.
8. Cross-platform: Unix (Linux, Mac OS-X, Android, iOS) and Windows
(Win32, WinCE, WinRT) are supported out of the box. Easy to port to
other systems.
9. Sources are in the public domain. Use for any purpose.
10. Comes with a standalone command-line interface (CLI) client that
can be used to administer SQLite databases.

Saving Data into a Database Introduction to SQL [1]
Basic database concepts:
[1] What is SQL?
SQL stands for Structured Query Language
SQL lets you access and manipulate databases
[2] What Can SQL do?
SQL can execute queries against a database
SQL can retrieve data from a database
SQL can insert records in a database
SQL can update records in a database
SQL can delete records from a database
SQL can create new databases
SQL can create new tables in a database
SQL can create stored procedures in a database
SQL can create views in a database
SQL can set permissions on tables, procedures, and views
http://www.w3schools.com/sql/sql_intro.asp

[3] Relational Database Management System (RDBMS)
1. RDBMS stands for Relational Database Management System.
2. RDBMS is the basis for SQL, and for all modern database systems
such as MS SQL Server, IBM DB2, Oracle, MySQL, Microsoft Access
and SQLite.
3. The data in RDBMS is stored in database objects called tables.
4. A table is a collection of related data entries and it consists of
columns and rows.
http://www.w3schools.com/sql/sql_intro.asp
Let’s have a quick look in SQL first...

[4] RDBMS Example

[5] Database operations
1. Database creation
2. Table(s) creation
3. Insert Record(s)
4. Update Record(s)
5. Delete Record(s)
6. Query
7. Drop Table(s)
8. Alter Table(s)
SELECT - extracts data from a database
UPDATE - updates data in a database
DELETE - deletes data from a database
INSERT INTO - inserts new data into a database
CREATE DATABASE - creates a new database
ALTER DATABASE - modifies a database
CREATE TABLE - creates a new table
ALTER TABLE - modifies a table
DROP TABLE - deletes a table
CREATE INDEX - creates an index (search key)
DROP INDEX - deletes an index
[6] SQL Commands

[7] Example SQL Commands
CREATE TABLE IF NOT EXISTS èmployee` (
ÈmployeeID` int(11) NOT NULL
AUTO_INCREMENT,
`Name` varchar(50) NOT NULL,
Àddress` varchar(100) NOT NULL,
`PhoneNumber` varchar(11) NOT NULL,
`Designation` varchar(50) NOT NULL,
PRIMARY KEY (ÈmployeeID`)
);
[a] Table Creation

INSERT INTO employee (EmployeeID, Name,
Address, PhoneNumber, Designation) VALUES
(NULL, 'Hasan', 'Mirpur, Dhaka', '01745534',
'Developer');
INSERT INTO employee (EmployeeID, Name,
Address, PhoneNumber, Designation) VALUES
(NULL, 'Rahim', 'Motijheel, Dhaka', '01956635',
'Designer');
[a] Insert Records

SELECT * FROM employee;
SELECT Name, Address FROM employee;
SELECT * FROM employee WHERE EmployeeID = 1;
SELECT * FROM employee WHERE Designation =
‘Developer’;
[b] Query Records

Saving Data into a Database SQLite in Android

Saving Data into a Database Questions...
Man who waits for roast duck to fly into mouth
must wait very, very long time.
-Chinese Proverb

Lecture 5: Storage: Saving Data Database, Files & Preferences

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Lecture 5: Storage: Saving Data Database, Files & Preferences