Question

I have a table where specific service providers will be store there-car shops for example.
The car shops offer various services.

My problem how to store in a column these services?
I could create a second table where the services are stored but that would needed if I wanted to provide search functionality-which my intention is not to, at least not now.

So how I would store all the services in one row(that corresponds to a specific car shop for eaxmple). It would be of the VARCHAR type as I see it.

Furthermore is it OK that a primary key in a table references a primary key in another table?

WHat else do I have to do?

I need to stress also that there might be cases where there might be a unique service offered by a service provider-that only one service provider offers a specific service.

Answer 1

you can have many-to-many relationship,

This table stores list of service providers.

CREATE TABLE ServiceProvider
(
    ProviderID INT NOT NULL,
    ProviderName VARCHAR(50),
    .......,
    CONSTRAINT tb_pk PRIMARY KEY (ProviderID),
    CONSTRAINT tb_uq UNIQUE (ProviderName)
);

CREATE TABLE ServiceList
(
    ServiceID INT NOT NULL,
    ServiceName VARCHAR(50),
    .......,
    CONSTRAINT tba_pk PRIMARY KEY (ServiceID),
    CONSTRAINT tba_uq UNIQUE (ServiceName)
);

this table maps the list of service provider to their services offered.

CREATE TABLE Provider_Service
(
    RecID INT,
    ProviderID INT NOT NULL,
    ServiceID INT NOT NULL,
    CONSTRAINT tbb_pk PRIMARY KEY (RecID),
    CONSTRAINT tbb_fk1 FOREIGN KEY (ProviderID) 
          REFERENCES  ServiceProvider(ProviderID),
    CONSTRAINT tbb_fk2 FOREIGN KEY (ServiceID) 
          REFERENCES  ServiceList(ServiceID),
    CONSTRAINT tba_uq UNIQUE (ServiceName, ProviderID)
);