Basic Database knowledge and database creation

Directory: 1. Basic knowledge of databases and database creation 2. Database interfaces 3. use ADO or ADO controls to access database instances that have been learning for a while, during the learning process, I encountered many problems. The first problem is what the database is? There is nothing in the brain. You can search for information online and summarize it continuously.

Directory: 1. Basic knowledge of databases and database creation 2. Database interfaces 3. use ADO or ADO controls to access database instances that have been learning for a while, during the learning process, I encountered many problems. The first problem is what the database is? There is nothing in the brain. You can search for information online and summarize it continuously.

Directory:

1. Basic Database knowledge and database creation

2. Database Interfaces

3. Use ADO or ADO controls to access the database

A database instance that has been learning for a while recently has encountered many problems during the learning process. The first problem is what is the database? There is nothing in the brain. You can search for information online and summarize it continuously. The above also gives you a simple list of directories and database articles, which will be presented one by one in the near future.

Let's not talk about it. Let's give a brief introduction to what is a database?

Data ):Is the physical representation of information. Data can become information after being processed, organized, and given a certain meaning.

Database (Data Base, DB for short ):A set of data that is stored on a computer storage medium in an organized, shareable, and correlated manner. In short, it is the data storage warehouse.

Databases can be divided into hierarchical models, mesh models, and relational models by structure. Each model corresponds to a type of database, that is, a hierarchical database, a mesh database, and a relational database. Relational databases are the most commonly used and easiest to manage. Here we will focus on relational databases:

I. Database Composition

1. Data Table: Table

A data table is a two-dimensional table formed by row and column arrangement of associated data. The database is just a framework, and the data table is actually the actual content. A database is composed of one or more data table groups. Each table can have a certain relationship.

2. Field: Field

Each column in a data table is a field that has the same data type. The name of each data item in the table header is called the field name. Such as name and gender.

3. Record: Record

Each row in a data table is a record, which is a set of field values.

4. KeyWord: KeyWord

Keywords are used for classification query of records in the database. Keywords can be classified into primary keywords and candidate keywords. There can be multiple candidate keywords in a data table, and there is only one primary keyword with different values.

5. Index: Index

A table can be saved or sorted in different order, that is, a table can have different indexing methods. Objective: To improve access efficiency.

Data Table:

2. Create a database

There are two ways to create an Access database:

1. Create a database in Microsoft Access

The method for creating a database in Microsoft Access is not described here. The focus is on the process of creating a database in Visual Data Manager.

2. Use VB to provide a visual data manager to create a database (take Access database as an example to learn how to create a database)

(1) Start the Visual Data Manager (using Access as an example)

Select "external program"> "Visual Data Manager" to open "Visdata"

(2) create a database

In the "Visdata" window, select "file"> "new"> "Microsoft access"> Version MDB to open the database creation dialog box. Name of the data database, saved. The "Database window" and "SQL statement" windows appear in the "Visdata" window.

(3) create a data table

1. Create a data table structure

* Right-click "Properties" and select "new table". The "table structure" dialog box is displayed.

* Click "add field" and "delete field" to add and delete fields.

* Click "add index" and "delete Index" to add and delete indexes.

* Click Generate table to close the table structure dialog box and return to the Database window.

2. Modify the data table Organization

* Right-click "Database window" and select "design" to open the table structure and modify it.

(4) input data

* In the database window, right-click the data table name and select open"

* Click "add", enter a record, and click "Update" to add a record.

* Click Close to exit the visualization Data Manager and complete database creation.

This article is the beginning of the database. We will continue to explore the database. You are welcome to raise your shortcomings.