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Java Holiday Calendar 2016 (Day18): Easily Create Database Content

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Java Holiday Calendar 2016 (Day18): Easily Create Database Content

You can use Java and Speedment together to easily analyze your database and generate code and content for it as well.

· Java Zone ·
Free Resource

Learn how to build stream processing applications in Java-includes reference application. Brought to you in partnership with Hazelcast.

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Today's tip is about creating database content. There are a number of ways to do this, ranging from writing our own entity beans combined with using JDBC directly to just fully automating the entire process.

Suppose we already have a database table like this:

mysql> explain country
+------------+-------------+------+-----+---------+----------------+
| Field      | Type        | Null | Key | Default | Extra          |
+------------+-------------+------+-----+---------+----------------+
| id         | int(11)     | NO   | PRI | NULL    | auto_increment |
| name       | varchar(45) | YES  | UNI | NULL    |                |
| local_name | varchar(45) | YES  |     | NULL    |                |
| code       | int(11)     | YES  |     | NULL    |                |
| domain     | varchar(10) | YES  |     | NULL    |                |
+------------+-------------+------+-----+---------+----------------+
5 rows in set (0.00 sec)


Then we could add the Speedment plugin and dependency to our POM and launch the Speedment graphic tool, which will analyze the database and generate code automatically for us.

After generation, we can do this:

Initialization

final MyApplication app = new MyApplicationBuilder()
    .withPassword("myPwd729") // Replace with the real pwd
    .build();

final CountryManager countries = app.getOrThrow(CountryManager.class);


Insert DB Content

countries.persist(
    new CountryImpl()
        .setName("Sweden")
        .setLocalName("Sverige")
        .setCode(40)       // Intentionally wrong, should be 46!!
        .setDomain(".se")
);


Update DB Content

countries.stream()
    .filter(Country.NAME.equal("Sweden"))  // Filter out Sweden
    .map(c -> c.setCode(46))               // Update code to 46
    .forEach(countries.updater());         // Apply the database updater


Read more about Speedment on GitHub here.

Follow the Java Holiday Calendar 2016 with small tips and tricks all the way through the winter holiday season.

Learn how to build distributed stream processing applications in Java that elastically scale to meet demand- includes reference application.  Brought to you in partnership with Hazelcast.

Topics:
java ,database ,mysql ,code generation

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