[B-frame-devel] b-frame 0.1.3

[Peter B. <pbe...@sn...>]

Hi,

<b-frame/> 0.1.3 has been released, visit http://www.b-frame.org/ and
http://sourceforge.net/projects/b-frame. With this release it is
possible to join tables to groups of type list or display, and to
customize the user input for the select operation. Some bugs have been
fixed.

The release can be downloaded from

http://sourceforge.net/project/showfiles.php?group_id=68958&release_id=151552



1. Join Tables to List and Display Groups

With this release it is possible to join tables to groups of type list
and display, respectively. Using a join makes it is possible to display
information not only from the table corresponding to a particular task
but also from related tables. As an example consider the following
Student Task.

     <bf-app:task table="student">
       <bf-app:task name="course_list" table="visit">
         <bf-app:group type="list">
           <bf-app:field name="institute_name" label="Institute"/>
           <bf-app:field table="professor" name="id" alias="professor_test_id" label=""/>
           <bf-app:field table="professor" name="name" label="Professor"/>
           <bf-app:field table="course" name="id" alias="course_test_id" label=""/>
           <bf-app:field table="course" name="title" label="Course" link="true"/>
           <bf-app:join table="course" on="visit_ref_course">
             <bf-app:join table="professor" on="course_ref_prof"/>
           </bf-app:join>
         </bf-app:group>
       </bf-app:task>
     </bf-app:task>

The tables course and professor are joined to the visit table for
displaying the course's title and the professor's name. Note that the
fields course.id and professor.id is given an alias because each field
of a group needs a unique identifier. When thinking about identifiers,
have in mind that each group is extended by <b-frame/> to include all
primary key attributes (but only the defined attributes occur on a
mask).

2. Customizing Queries

By default, the query of a top level task allows user input for the
primary key fields. With this release it is possible to define these
fields by using the <bf-app:query> and <bf-app:infix> tags.

     <bf-app:task table="student">
       <bf-app:query>
         <bf-app:infix name="and">
           <bf-app:field name="id" label="ID"/>
           <bf-app:field name="name" label="Name"/>
         </bf-app:infix>
       </bf-app:query>
     </bf-app:task>

The <bf-app:infix>'s name attribute defines the operator, e.g. and or
or. <bf-app:infix> tags may be nested.

Note that currently it is not possible to include fields from other,
joined tables into the condition of the query, this will become
available in the future.

3. Bug Fixes

  1. The Hsqldb data base doesn't seem to support the FOR UPDATE clause
     which is used by <b-frame/> to implement optimistic locking. In
     effect it was impossible to perform an update on Hsqldb. The new
     release configures the FOR UPDATE clause using the environment:
        o MySQL: FOR UPDATE,
        o Oracle: FOR UPDATE NOWAIT, and
        o Hsqldb: empty.
     Note that in case of using Hsqldb <b-frame/>'s optimistic lock is
     not completely multi user save because the record is not locked
     between reading and updating.
  2. Prior <b-frame/> versions where using the parameters task, action,
     and state for coding state information into HTML links. On the
     other hand, database attributes where also coded into links and
     forms, hence it was impossible to have database attributes task,
     action, or state. To avoid this collision the new release
     introduced prefixes for keys in links:
        o ctrl  for the control parameters task, action, and state,
        o data  for data, and
        o original  for the backup copy of the data used to implement
          optimistic locking.

4. Documentation

The tutorial at http://www.b-frame.org/applications.pdf has been
updated.

Bye,

Peter