[+] Modifications on MySQLDatabaseGateway & added a SQL Script

[Lei-Tin]

Modifications:

• Returns null for the methods: getUserData and getEntryData, both of which is returned when we cannot find the specified username / entry_id in the given bill.
• Added a SQL Script that generates a sample bill table, can be modified so that we can use this to append the information to any bill table we wish. Now, running this script creates a table called bill_999 and it contains some of the example entries that I have created. This can be used for demonstration purposes.

The data that will be generated is shown in the picture below:

Modifications (As of November 28), Part 2:

• Modified MySQLDatabaseGateway so that it incorporates another version of most functionalities, but dedicated for the splitEntry version.
• Added a QuerySplitEntryData class that is used specifically for split entries
• Made QuerySplitEntryData and QueryEntryData both inherit from QueryEntry, which fixes some code smell
• Fixed some small typos and some parts where I actually called INSERT INTO bill_{user_id}{split_bill_id}

Updated split bill data structure:
Now: All of the split bill will have the bill name being
bill_{user_id}_{split_bill_id}

And for the table structure, it is the same as previously defined.

[CharlotteChenyy]

👍👍👍

[xgao28]

The Javadoc in the beginning of each file could be more specific on how this chunk of code works.

Overall good(=•ェ•=)