First you describe the data in a text file, called Makumba Data Definition. It contains lines like:

name= char[30]                   ;Name
dob= date                        ;Date of birth
addresses= set                   ;Addresses of the person
addresses-> city = char[40]      ;City
addresses-> phone_number = int  ;Phone number

Say you call the above record a "Person". Makumba can use this information to perform the right action when manipulating the database or generating HTML output. Of course, complex applications have more types of data, with pointers from one to the other.

Makumba can generate SQL statements that create the needed tables and do read/write operations in a database of your choice. It currently supports MySQL, Informix, DB2, PostgreSQL and ODBC but many other database engines can be easily supported if needed.

At the interface level, Makumba can generate html for inserting, editing, viewing and deleting data from the database. You don't have to care about details of HTML forms, parsing the CGI arguments, composing SQL statements etc. All this routine work is done for you, but you can freely build upon it.

For instance, following code will show a list of persons and their phone numbers. You mix HTML and Makumba jsp tags to get the desired view.

<mak:list from="general.Person p, p.addresses a" where="a.city = 'Vienna'">
  <b><mak:value expr="p.name"/></b> was born on <mak:value expr="p.dob"/><br>
  Phone numbers:
  <mak:list from="a.phone_number n" separator=", ">
    <mak:value expr="n"/>
  </mak:list>
</mak:list>

Makumba will generate the appropriate queries needed to display the result and optimise them so as to execute the least possible number of queries, in order to increase performance.

If you wish to add a new Person to your database, you can just write the following code. It takes care of creating an input form in HTML, and arranges for all necessary database commands to be performed after submit (including the creation of subrecords, in our example a new address object).

<mak:newForm type="general.Person" name="person" action="listPersons.jsp">
        Name : <mak:input name="name"/> <br>
        Date of birth : <mak:input name="dob"/>
        <mak:addForm object="person" field="addresses">
          Phone number: <mak:input field="phone_number"/>
        </mak:addForm>
</mak:newForm>

Makumba will choose appropriate input controls for each datatype, as indicated by the data definition above.

Behind the HTML pages, developers can optionally write "business logic" in Java that adds certain operations to the basic actions (insert, edit, delete). For this, the full power of Java, enhanced with the Makumba API for e.g. database handling, is available.

You can see more in a slightly more detailed example.