Database access

Our next objective was to introduce database interaction. We decided to have the following classes for it.

Tabular	To show multiple records in a grid
FreeForm	To show one record with multiple fields
DataStore	To interact with database

In addition two classes were used internally.

• RecordSet - to hold a retrieved record
• Column - to hold information about columns in a tabular and rows in freeform

The action class was also extended to support a call to a server side function created as a part of the page definition. To both Tabular and FreeForm, we added some Ajax like features so that:

• A HTTP XML request can be send from the send from a client action, attached to a tabular column, which will invoke a server side function written in the page.
• The server side function can create a class, like FreeForm, and sends it to the client
• The FreeForm is repainted in the client

So there is a tabular portion in the screen which displays name of all the participants. There is also a FreeForm portion which displays more detail. On click on any name the data is fetched from the server side and the FreeForm is updated.

We created a database of all people attending the BarCamp at Chennai to get the page working.

The code looks like this:

module PageTabular

def showFreeform(pNameClicked)
    datastore = DataStore.new("tsgpdc2k", "ubuildmya", "sets")
    datastore.databasename = "SessionDB"

    freeform = Freeform.new
    freeform.name = "DynamicDisplay"

    style = Style.new
    style[:font_size] = 12
    style[:color] = "blue"

    liveNewsText = Text.new("")
    liveNewsText.style = style
    newsDetail = Text.new("")
    newsDetail.style = style
    presentation = Text.new("")
    presentation.style = style
 
    freeform.add("Name", "Attendee Name", liveNewsText)
    freeform.add("Details", "Attendee Details", newsDetail)
    freeform.add("Presentation", "Presentation Given", presentation)

    datastore.sql  = "select * from Attendees where name= ?"
    datastore.setParameter(1, pNameClicked)
    freeform.columns = datastore.select

    return freeform
end

def pageText
    page = Page.new(:PageTabular)

    datastore = DataStore.new("tsgpdc2k","ubuildmya","sets")
    datastore.databasename = "SessionDB"
    datastore.sql  = "select * from Attendees"

    freeformstyle = Style.new
    freeformstyle[:left] = 300
    freeformstyle[:background_color] = '#A5c3ef'

    freeform = Freeform.new
    freeform.name = "DynamicDisplay"
    freeform.width = 350
    freeform.style = freeformstyle
    freeform.valign = :top

    tabularsection1 = Tabular.new
    tabularsection1.maxRow = 100
    tabularsection1.height = 100

    style = Style.new
    style[;color] = "blue"

    name = CheckBox.new('')
    actionclass = Action.new
    actionclass.add(page, 'showFreeform', [name], [freeform])
    actionclass.add(freeform, "refresh")
    name.event[:Click] = actionclass
    name.style = style

    tabularsection1.add("Name", "Attendee Name", name)
    tabularsection1.columns = datastore.select

    page << [tabularsection1, freeform]

    return page
end
end