Learn the-----of the database Day 1-Some basic concepts of the database

a little bit of database-----Day 1-Some basic concepts of the database

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Introduction to this section:

This section mainly introduces some basic concepts of the names of some databases, so that you have a basic understanding of the database!

1. "Database" and "Database management system"

A: Database, simple to understand is " storage of Data Warehouse "

The database Management system,DBMS, is known as the system that manages the former,

Now there are many DBMS, the more common is: Mssql,mysql,oracel,sqlite and other database management system, and the author

Using the MSSQL 2008, of course you can choose the appropriate DBMS according to your own needs, perhaps you can directly use the Android

Built-in SQLite to learn also OK ha! DBMS is used to manage the database , we want to maintain or find the data, we just need to

According to the SQL specification, if we're looking for someone, we just need to tell the DBMS what the person is, and he'll help us find it.

Where to find, how to find, this is none of our business! We don't have to worry about how the bottom layer is implemented, so we can put more energy into

To the development of business systems!

The simple point is that:

We just have to tell the DBMS, "What to do" without caring about "what to do", and the DBMS will decide for itself a better

How to complete the operation!

2. Some nouns related to the database:

3. The concept of a table association:

In actual development we may encounter this situation:

Look at this table, we found that the company's relevant information is duplicated, can we extract the part about the company?

Well, then we'll get the rest of the stuff out! Write a company Information sheet!

The next step is to create an association between the two tables, that is, to modify the people table, and the new staff table is as follows:

We can find the corresponding company information according to the company number, and when the company information changes, it is often changed.

of convenience, above this The way to correlate two tables by the primary key of the second table is called "Table association"

and this fields that are associated to other tables , also called " FOREIGN Key ", like here." Company Number "

Learn the-----of the database Day 1-Some basic concepts of the database