W2 Thu 09082018

Topic: Database

Primary Key (PK) is the ID for each data.

When the system relying on unique key, php need to attempt inserting new data. and get error or success message from database

When the duplication checking process is done in php process, the database will be asked for the duplication rather than try to put new data.

The drop-down list can be gathered from database and it makes easier management.

Standard time format is 'YYYY-MM-DD HH:MM:SS.MMMM'

Use assessment work plan to distribute workload.