coding many to many relationship in c++ sqlite3 - c++

Question

I trying to code a many to many relationship in c++ sqlite3.
in the diagram below,
managers can add many job opportunities.
jobs opportunities is being add by many managers
my create table statements
"CREATE TABLE Manager(" \
"manager_id INTEGER PRIMARY KEY NOT NULL,"\
"name varchar(45) NOT NULL);"
"CREATE TABLE jobs ("
"jobId INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,"\
"jobTitle varchar(45) NOT NULL);"
"CREATE TABLE Add ("
"manager_id,jobId INTEGER PRIMARY KEY NOT NULL,"\
"date varchar(45) NOT NULL,"\
"FOREIGN KEY(manager_id) REFERENCES Manager(manager_id),"\
"FOREIGN KEY(job_id) REFERENCES jobs(job_id));";
my manager table is populated with the following information
1|john
2|bob
let's say manager john has added two jobs,jobTitle jobA and jobB
then my insert statement code will look like this.http://pastebin.com/0E8CzPgX
then my jobs tables is populated with the following information
1|jobA
2|jobB
the final step is to take the id of john(manager id = 1) and the two jobsId(1,2) and add it inside
the add table. I don't have an idea of how should I code
so that the add table will become like this.
add table
manager_id|job_id|date
1 | 1 |30-01-2014
1 | 2 |30-01-2014
please advise.thanks

Answer 1

Do you mean something like
sql = "INSERT INTO Add(manager_id,jobId,date) VALUES (?,?,?);";
?
Your problem seems to be that you defined jobID to be the primary key of the table Add, which you don't need.
jobId INTEGER PRIMARY KEY NOT NUL
A common approach to many-to-many relations in a database is to include an intermediate table.
This intermediate table (let's call it Manager_jobs) would have at least 2 columns, both referring to other tables via foreign key. The first attribute would be the primary key of Manager, the second one the primary key of jobs.
Each time you add a job, you just add an entry to Manager_jobs with the foreign keys respectively.
So, Manager_jobs would look like this:
ManagerID | JobID
==========|======
4 | 2
3 | 2
4 | 1
As you can see, Manager_jobs can encode that a Manager has multiple jobs assigned and vice versa.
This approach, of course, requires you to have some form of primary key for both data tables.