A Lightweight Database Library for Android.

Fetch the code and import it as Eclipse project. Than include it in your own Android project (Project Properties -> Java Build Path -> Projects -> Add…). A user-friendly jar in two versions (dex compiled and sun-java compatible) is planned for the first release.

Just extend your class from Table and set a DB version on it:

@TableMetaData(version = 1)
public class Category extends Table {

	@Column
	private String name;

	@Column(notNull = true)
	private int budget;

	public Category(final Context context) {
		super(context);
	}
	
	//and some getters&setters
}

With the @Column-Annotation you define a column in the DB. You don’t need to define a Primary Key. This is alreade done by Table’s “_id” Column.

Now, you can call all CRUD-Method on Category:

Table cat = new Category(getContext());
cat.setBudget(42);
cat.save(); //"update or insert"

Table cat = new Category(getContext());
cat.find(42);
cat.setName("foo");
cat.save();

cat.delete();

Of course, you can extend your Table implementation with your specialized CRUD-Methods:

public boolean findByName(final String name) {
	Cursor c = db.query(getTableName(), getColumnNames(), "tableName='" + name + "'", null, null, null, null);
	return fillFirst(c);
}

The super class Table provides all methods you need, like getTableName(), getColumnNames(), fillFirst©…

When creating a table instance, this table will immidiatly created in the DB (when it’s not existing, yet). Afterwards, we will look in our Metadata-table to compare the current table version with the new created one. When they differ, onUpgrade(int fromVersion, int toVersion) will be called. The default behaviour is to drop the current table, but you can simply override the method to provide your own upgrade handling.

The following types are currently supported:

Flag for “NOT NULL”-constraint

Flag for “AUTOINCREMENT”-constraint

Flag for “PRIMARY KEY”-constraint. Though the Table-class holds the primary key for each table, you won’t use this.

int value for an Android ressource to bind with this column. It’s not interpreted anywhere in androiDB, but you can use this value for your own (probably in your CursorAdapter).

Array of index names, which should include this column. Examples:

• You want to create an index on your columns “firstname” and “lastname”. Just add to each column

@Column ( indexNames = {"idx_name"}) firstname @Column ( indexNames = {"idx_name"}) lastname

• You want to speed up single searches for firstname, too:

@Column ( indexNames = {"idx_name", "idx_firstname"}) firstname @Column ( indexNames = {"idx_name"}) lastname

Don’t use SQL reserved words as column names! I could quote all column names, but SQLite don’t behave like expected:

sqlite> CREATE TABLE IF NOT EXISTS Metadata ( '_id' INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, 'table' TEXT NOT NULL);
sqlite> insert into metadata ('table') values ('fjdksla');
sqlite> select * from metadata;
1|fjdksla
sqlite> select table from metadata;
Error: near "table": syntax error
sqlite> select 'table' from metadata;
table

You have to take care of your db and cursor instances. When you don’t need them anymore, you have to call explicitly close()!

• Example: github.com/mattelacchiato/androiDBExample

• Tests: github.com/mattelacchiato/androiDBTest (depending on androiDBExample)

At www.blaulabs.de/2010/09/forschungswoche-androidb/ you can find a german blogpost about this project.

A presentation can be found at prezi.com/24kxq2purtmf/androidb/

Android, db, database, sql, sqlite, orm, or-mapper, hibernate, framework, libary, androiddb