Question

I have 3 tables. I create a task and upload a resource at the same time. The data is saved in two tables – one for task information and one for the resource.

I am trying to insert the primary keys of the two tables into a third table. The first table is called Task and has task_id as a primary key, task_name and task_description. The second one is – Resource and has resource_id as a primary key and resource_name. Both id’s have the auto increment option, so when I enter data to the table, I don’t fill the ids.

I want to insert task_id and resource_id into a third table called Task_resource. It has a primary key task_resource_id(again with auto increment option).

The question is how to do it, since I don’t know the id’s?

The reason for this is that one task can have many resources and in the third table I can combine them, and therefore search of them(for example something like SELECT data from the other 2 tables WHERE task_id=1).

I am having a asp.net Web Application and a mssql database. I use c#.

I know that a possible solution could be inserting a column called task_id into the Resource table which references the task_id in Task.

But then again, how to insert that id, since I don’t know it ?

Answer 1

Do the insert on the first table and then return the scope_identity() from the query. Then when you insert into the second table you have the ID? Or if you are using LINQ

//create the object
Task task = new Task{

task_name = src.taskName,
task_description = src.taskDescription

}

context.Tasks.InsertOnSubmit(task);
context.SubmitChanges();

//do second insert
Int32 taskIDFromLastInsert = task.task_id;

Resource res = new Resource{

resource_name = scr.ResourceName,
task_id = taskIDFromLastInsert // optional if you want to change your structure

}

context.Resources.InsertOnSubmit(res);
context.SubmitChanges();

Int32 resourceIDFromLastInsert = resource_id;

You now have both ID’s if you really want to insert into third table

It is a clean way to reference your data

After the inserts run your query against the data.