Database technology is an important part of modern information science and technology and the core of computer data processing and information management systems.

The form of data can be numbers, text, graphics or sounds, etc.

Characteristics of data management in the manual management stage: data is not saved; is not shared; data needs to be managed by the application itself; there is basically no concept of files during this period, and the organization of data must be designed by programmers themselves

Characteristics of data management in the file management stage: data can be saved for a long time; has a certain degree of independence; is managed by the file system; the forms of data files have been diversified

The characteristics of data management in the database system stage: provide users with a convenient user interface; provide data control functions; have high data independence; use data models to represent complex data structures

Database system features

Database management system functions

Database architecture

The relational data model, referred to as the relational model, consists of three parts: data structure, relational operations, and relational integrity.

A relationship corresponds to a two-dimensional table

The minimum attribute or set of attributes that can uniquely identify a row in a table is called the primary key.

In a relational database, in order to realize the connection between tables, the main key of one table is placed in another table as the link between data. These attributes that have a connection role in another table are called foreign keys.

The properties that a relationship must satisfy

Entity integrity constraint rules: means that the primary key in the relationship does not allow null values

Referential integrity constraint rules: also called referential integrity rules, which means that records that do not exist cannot be referenced.

User-defined integrity constraint rules: refers to constraints on the data type, length, value range, etc. of each data in the relational schema, which are uniformly controlled by the user through the data language provided by the relational DBMS.

Three elements of relational algebra operations: [operand, result] (relationship), operator

Traditional set operations include union, intersection, and difference, which are used to implement data operations such as insertion, deletion, and modification.

Specialized relational operations include projection, selection, and connection, used to implement data queries

SQL consists of four parts: data definition, data manipulation, data control, and regulations for using embedded SQL.

Main features of SQL language

The content of database design includes two aspects: structural feature design and behavioral feature design.

Basic principles of database design: simplicity, non-redundancy

Database design steps are generally divided into seven stages: planning, requirements analysis, conceptual design, logical design, physical design, implementation, operation and maintenance stages

Access is a powerful and easy-to-use desktop relational database management system

The application builders provided by Access2010 include: table builder, query builder, macro builder, report designer

In the design view of the table, each field has a design category. Access allows nine data types, text, note, number, date/time, currency, yes/no, CLE object, hyperlink, and attachment.

You can use the LIKE operator to find field values ​​that match the specified pattern. For the pattern, you can specify a complete value, or you can use wildcards to find values ​​within a certain range.

The process of using database technology to manage data

Steps to establish a relationship between tables: Open the database - start the relationship tool - add a relationship table - view the relationship diagram - create a table relationship

Index is a technology that arranges the records in the data table in an orderly manner based on the order of a certain keyword or keyword expression value in the data table.

A view is a special type of data table, which often consists of some text fields or records in one or more tables (or views).

The purpose of creating a view

SQL is a standard relational database language that integrates data definition, data manipulation, data query, and data control functions. Its core function is query

Characteristics of SQL language

SQL clause

The form is the interface between the user and the Access database. It is an operation interface for users to use Access to process their own data.

The elements that make up a form are called controls

Forms are divided into: column form; tabular form; data presentation form; subform; multi-page form; pivot table

There are three ways to create a form: automatically create a form, use the form wizard, and use design view.

Controls are objects on a form or report that are used to display data, perform operations, or decorate the form or report.

A report is an object in the Access database, which prints out formatted data information according to specified rules.

The data source of the report can be a data table or query. The report can group, calculate and summarize the data.

Functions of reports: output data in formatted form; summarize data in groups; display chart data; can output various styles of reports; can perform statistical calculations on data; can sneak into images or pictures to enrich data display

Access's report operation provides four views: report view, print preview view, layout view, and design view.

Type of report: Column format; Table format; Pivot chart, Pivot table report; Label report;

Report creation process: select the record source, select the report tool, and create the report

In Access, programming is the process of adding functionality to a database using Access macros or Visual Basic for Applications (VBA) code

Deciding whether to use macros, VBA, or both depends largely on how you plan to deploy or distribute your database

Macros are tools that allow you to automate tasks and add functionality to forms, reports, and controls