Question

I am trying to create a “Task” schema in my database. One field is “blockedBy” which represents another Task that is blocking this current task.

I am new to SQL Server and databases in general. How can I create the table properly? It seems like the only valid options are numbers or text.

Should I just store the ID number of the other “Task” in the “blockedBy” field or is there a better way?

Answer 1

I assume:

• you have a schema called “Tasks” in a database in SQL Server
• you then have a table (say, AllTasks) that stores task information
• you would like to have a field called blockedby that indicates which existing task is blocking the current task

Here’s my proposal of columns, and an example of how the data would look like:

TaskID   TaskName    TaskDescription .....   TaskBlockedBy
------   --------    ---------------         -------------
1        Eat         Eat food                <NULL>
2        Drink       Drink, um, water        <NULL>
3        Sleep       Ah, peace!              <NULL>
4        Wake Up     Crap                    3

Wake up task in row 4 is blocked by Sleep task in Row 3.

Table fields will have datatype:

TaskID int (identity/autonumber)
TaskName nvarchar(50) not null
TaskDescription nvarchar(200) not null
TaskBlockedBy int

If you anticipate multiple existing tasks blocking a task, break up the table into 2 tables: AllTasks and BlockedTasks. AllTasks table will not have TaskBlockedBy field anymore and BlockedTasks and its data will look like this:

BlockID  TaskID  BlockedBy
-------  ------- ----------
1        4       3
2        4       2

This indicates that task of Wake Up was blocked by Sleep and what the user drank before sleeping.

HTH