How do I add dynamic data to a database table? - mysql

Question

I am trying to create a database for gym workout plans. This would have each member's workout plan, which comprises multiple exercises.
My question is: given that one member might have 5 exercises, another member 3, another 6, and so on, how can I store this in the database?
My thought process has been around hardcoding a set number of exercises in the table, and give the possibility of them being null (for exemple 10 exercises, but if you only use 5 exercises, everything else can be stored with nothing). But this doesn't feel very correct.
I am using MySQL for this.

Answer 1

Like #Sami pointed out, you are going to work on whats called a relational database.
Below is a simple database structure that will help you get started.
Members table
Table Name: tbl_members
Table Structure:
|member_id|member_name|member_contact|
Exercise or schedule table
Table Name: tbl_member_schedule
Table Structure:
|schedule_id|member_id|assigned_date|Schedule
In the tbl_member_schedule you can store the entire schedule as a JSON structure or you can further normalize. Since this is an example I am storing the entire schedule in JSON format inside the Schedule field.
Now when you want to retrieve the schedule of a specific member (member id: 1) you can query the database as follows:
select
tbl_members.member_id, tbl_members.member_name,
tbl_member_schedule.Schedule
from
tbl_members join
tbl_member_schedule on tbl_members.member_id = tbl_member_schedule.member_id
where
tbl_members.member_id = 1;
So you JSON structure for your schedule could be
{
day1: [
{exerciseName: 'dumbbell curls', reps: '8 x 4'},
{exerciseName: 'leg extension', reps: '8 x 3'}
],
day2: [
{exerciseName: 'dumbbell curls', reps: '8 x 4'},
{exerciseName: 'leg extension', reps: '8 x 3'}
]
}