I have one member table structure in SQL Server:
member_table
memberid name address email
111 aaa IND a@a.com
222 bbb UK b@b.com
Now I want to give such facility that one member can follow as many other members. How can I do that?
Should I create a new table? Should I use any flags?
I'm thiking to create a new table and give Member table
You can create another table consisting of two attributes (member_id, follows_member_id) This table keeps records of each member following other members. Both attributes reference your members table. This is a standard approach in creating a many-many relation as it is normalized. read more
I would create a junction table with a key on both member_ids to ensure there is at most 1 row.
I try to not cater to YGWITs (your gonna want it), but it seems a subscription table would call for some additional metadata such as the date the subscription starts or the last access date to know if there is new activity.
I would end up with something like this:
CREATE TABLE [dbo].[member_subscription](
[member_id] [int] NOT NULL,
[target_member_id] [int] NOT NULL,
[date_created] [datetime] NOT NULL,
[date_last_visit] [datetime] NULL,
CONSTRAINT [PK_member_subscription] PRIMARY KEY CLUSTERED
( -- key on both member_id fields
[member_id] ASC,
[target_member_id] ASC
) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
-- Foreign key contrain for member_id
ALTER TABLE [dbo].[member_subscription] WITH CHECK ADD CONSTRAINT [FK_member_subscription_member] FOREIGN KEY([member_id])
REFERENCES [dbo].[member] ([member_id])
GO
ALTER TABLE [dbo].[member_subscription] CHECK CONSTRAINT [FK_member_subscription_member]
GO
-- Foreign key contrain for target_member_id
ALTER TABLE [dbo].[member_subscription] WITH CHECK ADD CONSTRAINT [FK_member_subscription_target_member] FOREIGN KEY([target_member_id])
REFERENCES [dbo].[member] ([member_id])
GO
ALTER TABLE [dbo].[member_subscription] CHECK CONSTRAINT [FK_member_subscription_target_member]
GO
-- Default value for date_created
ALTER TABLE [dbo].[member_subscription] ADD CONSTRAINT [DF_member_subscription_datecreated] DEFAULT (getdate()) FOR [date_created]
GO
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.