= Examples: FirstStepWithMySQL =

Simulates a very simple URL tagging application a la [http://delicious.com/ delicious.com], which allows users to tag any URL on the internet with one or more tags/labels. See also [wiki:Examples/FirstStep FirstStep], which does the same thing in memory.

== Obtain, compile and run ==

 1. Download FirstStepWithMySQL from the [wiki:Docs/Downloads downloads page], and uncompress ([wiki:Docs/TardBzipd instructions])
 2. Run ant to compile and run, e.g. `ant build run`
 3. Two apps will run:
   * The first app instantiates some objects representing bookmarks and tags in a graph, which is persisted in MySQL, using it as a key-value store.
   * The second app reads the graph from the database and traverses the graph to print out the data in different ways

== Annotated source code ==

Compare with [wiki:Examples/FirstStep FirstStep], which keeps the object graph in memory only. The key difference are the following lines:

Instead of creating a MeshBase in memory:
{{{
    MeshBase mb = MMeshBase.create();
}}}
we are creating a MeshBase using the [wiki:Store] abstraction:
{{{
    MeshBase mb = StoreMeshBase.create( store );
}}}
where `Store` could be any kind of store supporting [wiki:Store] abstraction. In this example, we use MySQL because many developers are familiar with it and !InfoGrid contains a MySQL-based implementation of [wiki:Store] called `MySqlStore`. We instantiate it as follows:
{{{
    MysqlDataSource ds = new MysqlDataSource();
    ds.setDatabaseName( "test" ); // name of the database

    MysqlStore store = MysqlStore.create( ds, "test" ); // name of the single table used in this example app
    store.initializeIfNecessary(); // will create table if not there, but does not touch data
}}}
To run the same example using PostgreSQL? Simply instantiate `PostgresqlStore` instead. Or `FilesystemStore` or `HadoopStore`...

Easy? Take the [http://www.surveymonkey.com/s/Z3Q2CJP 1-minute survey]. Feel free to ask questions on the MailingLists ...