Getting Started

Delia requires Java 8 or higher.

It can be obtained from Github, or from Maven (available from Maven central):

<dependency>
  <groupId>org.delia-lang</groupId>
  <artifactId>delia</artifactId>
  <version>0.2.0</version>
</dependency>

We will use the H2 database for this tutorial. Add it to your Maven pom.xml file:

<dependency>
   <groupId>com.h2database</groupId>
   <artifactId>h2</artifactId>
   <version>1.4.200</version>
</dependency>

Configure Your Database Connection

The following Java code will configure Delia for the H2 database.

ConnectionInfo info = ConnectionBuilder.dbType(DBType.H2).jdbcUrl("jdbc:h2:~/test").build();
Delia delia = DeliaBuilder.withConnection(info).build();

Define our Database Types

We define database types by writing some Delia source code. Normally Delia source would be in a text file, but for simplicity we'll define it directly in Java. We'll define a Customer type with two fields. We will also add some Delia statements to insert a record and then query for it.

String s1 = "type Customer struct {id int primaryKey, name String } end";
String s2 = " insert Customer {id: 1, name: 'Andrew Gonzalez'}";
String s3 = " let cust = Customer[1]"; //query by primary key

String deliaSource = s1 + s2 + s3;

Execute the Delia Source Code

When we execute the delia source code, Delia creates a Customer database table, and then peforms the insert and query. The result is available as a DValue object.

DeliaSession session = delia.beginSession(deliaSource); //execute

ResultValue res = session.getFinalResult();
DValue dval = res.getAsDValue();
System.out.println(dval.asStruct().getField("id").asInt());
System.out.println(dval.asStruct().getField("name").asString());

The output would be:

1
Andrew Gonzalez

Do another query

Once we have compiled the type definition we can execute additonal Delia statements. Let's do another query;

String s4 = " let cust2 = Customer[name like '%Gon%']"; //SQL LIKE expression

DeliaSession session = delia.continueExecution(s4); //execute

ResultValue res = session.getFinalResult();
DValue dval = res.getAsDValue();
System.out.println(dval.asStruct().getField("id").asInt());
System.out.println(dval.asStruct().getField("name").asString());

The output would be:

1
Andrew Gonzalez

Dao

Executing Delia source code is powerful, but it is often simpler to use the Delia DAO (Data Access Object). The DAO provides a CRUD-like API for doing database operations. Internally it is executing Delia source code, like our previous example.

Use the Dao

DeliaDao = new DeliaDao(delia);
dao.initialize(s1); //compile Delia and create tables

dao.insertOne("Customer", "id: 1, name: 'Andrew Gonzalez'");
ResultValue	res = dao.queryByPrimaryKey("Customer", "1");

DValue dval = res.getAsDValue();
System.out.println(dval.asStruct().getField("id").asInt());
System.out.println(dval.asStruct().getField("name").asString());

The output is the same as before:

1
Andrew Gonzalez

Next, The REPL.