How to insert into table that has many-to-many relationship?

How to insert into table that has many-to-many relationship?

MySQL – How to insert into table that has many-to-many relationship Ask Question Asked7 years, 8 months ago Active5 years, 4 months ago Viewed39k times 25 24 I have a table of persons. Each person has a property and many persons may have a certain property. So this is a many-to-many relationship.

How to handle a many to many relationship with PHP?

During the processing of this form the user will be able to select an occurrence of ‘A’, then press a control (a button or a hyperlink) which will pass the identity of the selected occurrence to a second form which I have identified as .

Can you have B to B in one to many relationship?

You can have A-to-B in a ‘one-to-many’ relationship, or B-to-A in a ‘one-to-many’ relationship, but you cannot have both at the same time. So what are we to do? The solution is to create a new table which will act as the ‘many’ in two ‘one-to-many’ relationships, with each of the original tables acting as the ‘one’.

Which is an example of a many to many relationship?

The example I have encountered several times is where each entry covers a different date range causing only one to be regarded as ‘current’ on any particular date, thus providing a history of values over a period of time. However, I shall leave the solutions to these additional problems to a later date.

Which is better multiple tables or one large table?

Having multiple tables is cleaner and probably theoretically better. But when you have to join 6-7 tables to get information about a single user, you might start to rethink that approach. I would say it depends on what the other tables really mean. Does a user_details contain more then 1 more / users and so on.

Why are MySQL tables always on the same record?

If user activity is often not very interesting, then it might just be a nuisance to always have it on the same record, for performance and maintenance reasons. If some data, like settings, say, are accessed very often, but simply contains too many fields, it might also not be convenient to merge the tables.

When is it better to split a table?

(a) if different people are going to be developing applications involving different tables, it makes sense to split them. (b) If you want to give different kind of authorities to different people for different part of the data collection, it may be more convenient to split them.