Database Storage Engine Project M1 Database Design

= About the milestone=

This milestone includes creating documentation and descriptions of the database schemes explained at Database Storage Engine Project.

=Questions : Database Layout=

This is the design to store survey, section and question information and their related metadata.



=Responses : Flat Database Layout=

This is the layout we propose for storing survey responses in a single database table.



=Responses : Multitable Database Layout=

This is the layout we propose for storing survey responses in multiple tables. Responses for each question get stored in a seperate table.



=Responses : Sectionflat Database Layout=

This is the layout we propose for storing survey responses in multiple tables. Responses for each section get stored in a seperate table.



=Question Type mappings=

These are database mappings for the question types presented here. Since the question types are presented as single questions, there is no difference between the 3 proposed database layouts.

Mappings for QuestionType classes to table columns
= Todo=
 * Design flat DB layout (Done)
 * Design normalized DB layout (Done)
 * Design section-flat DB layout (Done)
 * Keep in mind all the Question types supported by LimeSurvey1 : Question types (Done)
 * Problem with loops with current response layouts (sectionflat and multitable), flat has no support for loops. (Done)

= Discussions=

Comments and ideas here please:

Metadata requirements for databases
- time question displayed/made available to participant (added by Jason)

this may be an indication of when the page was served to the participants browser (time can be generated by web server/php) or in the case of conditional questions, it may need to indicate the time that the question became visible on the page (in which case it may need to be generated by javascript, with all those inherent problems.. maybe it should indicate how many seconds since the page was loaded, and that can be added to the page-load time?)

- time question answered by participant (added by Jason)

this may be a recording of the time that the data in the question was posted (time could be generated by web serer/php) or the time that the question lost focus (after having gained it) - which would be a javascript issue

Any other metadata requirements?