Initial thought process:
Design a script which was simple and user friendly. Integrate procedures/functions to extract data under the hood. I focused on giving the user the option to retrieve information based on a time period, meaning using start date and end date to define a search constraint. For example, if a user wants information from 1-MAR-12 to 8-MAR-12, he or she can plug those dates in as search parameters.
Queries: I designed the queries to answer the project questions.
Scripts: pop_fact_table.sql, which means populate fact table, receives 2 parameters type, DATE, uses the dateas conditions within a select statement to create a cursor.These parameters are used to set a time period boundary. Also the order_items idsare extracted because they are unique and I used them as a condition to get theoi.movie_id, dml.distributor_id, store_id, o.total_payment, o.tax, number_of_itemsdata from multiple tables. I used order_completed_date because I felt it was importantto extract information for orders completed instead of just using the ordering date.Ordering date does not mean the order was completed. Also I fed this date intoa function which could build my time dimension table and return the time_id to insert into the facts table. Finally, the information gathered from order_items were inserted in the facts table.
- Fill_time_dim.sql receives a parameter type, DATE, from pop_fact_table.sql, analyzes the date, then determines the month, quarter and year in which it belongs. Finally it uses this data and a generated time_id from sequence to populate the time dimension table.
- Star_schema_table.sl drops and creates the shell for the 4 dimensions tables and the fact table.
- Add_constraints.sql sets the 4 dimension primary keys as primary and foreign keys on the facts table.
- User_interface.sql is used to simulate a user's terminal requesting information. Initially, it builds the table shells and adds constraints. Once the user determines his/her search time period, data is etracted from the operational database and is placed in the facts table.