The structural hierarchy of the access database

This includes databases, data tables, fields, filters, and more.

The purpose of access is twofold:

1. Used for data analysis: Access has strong data processing and statistical analysis capabilities, and can easily carry out all kinds of summary and average statistics by using the query function of ACCESS. In addition, the conditions for statistics can be flexibly set.

For example, when statistically analyzing data of tens of thousands of records, hundreds of thousands of records and above, it is fast and easy to operate, which cannot be compared with Excel.

2. Used to develop software: Access is used to develop software, such as production management, sales management, inventory management and other enterprise management software.

The structural hierarchy of access data refers to the organizational relationship of data. Obviously, we know that records are made up of multiple fields, tables are made up of multiple records, and databases are made up of many databases -- > data tables -- > records --- fields.

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The basic structure of the database.

The basic structure of the database is divided into three levels, reflecting three different perspectives on the database.

1) Physical data layer. It is the innermost layer of the database and is the collection of data that is actually stored on the physical storage device. These data are raw data, objects that are processed by the user, and consist of bit strings, characters, and words processed by instruction operations described by the internal pattern.

2) Conceptual data layer. It is the middle layer of the database and is the overall logical representation of the database. It points out the logical definition of each data and the logical relationship between the data, which is a collection of stored records.

It deals with the logical relationship of all the objects of the database, not their physical condition, and is a database under the concept of database administrator.

3) Logical data layer. It is a database that is seen and used by a user, and represents a collection of data used by one or some specific users, i.e., a collection of logical records.

The connections between the different layers of the database are transformed by mapping. The database has the following key features:

1) Realize data sharing. Data sharing includes all users who can access the data in the database at the same time, and also includes users who can use the database through interfaces in various ways and provide data sharing.

2) Reduce data redundancy. Compared to the file system, the database realizes data sharing, which eliminates the need for users to create their own application files. Reduces large amounts of duplicate data, reduces data redundancy, and maintains data consistency.

3) Data independence. The independence of data includes the independence of the logical structure of the database and the application in the database, and also includes the change of the physical structure of the data without affecting the logical structure of the data.

4) Centralized control of data. In file management, data is in a decentralized state, and there is no relationship between different users or the same user in different processes with their files. The database allows for centralized control and management of data, and a data model that represents the organization of various data and the connections between them.

5) Data consistency and maintainability to ensure the security and reliability of data. These include: Security controls:

to prevent data loss, erroneous updates, and unauthorized use; Integrity control: to ensure the correctness, validity and compatibility of data; Concurrency control: allows multiple access to data in the same time period, and prevents abnormal interaction between users; Fault discovery and recovery:

The database management system provides a set of methods to detect and repair faults in a timely manner, thereby preventing data corruption.

The first layer is the table object and the query object, which are the basic objects of the database, which are used to store data and query data in the database.

The second layer is form objects, report objects, and data access pages, which are direct-to-user objects that are used to apply the system's data input and output and drive control.

The third layer is macro objects and module objects, which are **type objects. They do complex database management and automated data management by organizing macro operations or writing programs.

The first level is the table object and the query object, which are the basic objects of the database and are used to store data in the database and query data.

The second level is form objects, report objects, and data access pages, which are direct-to-user objects that are used for data input and output and driven control of the application system.

The third level is macro objects and module objects, which are **type objects that are used to organize macro operations or write programs to complete complex database management work and automate data management.

The basic object of the first-level database should be tables.

Database objects, table objects, form objects.

Answer]: bb. [The structure level of parsing access is one database, one data table, one record, and one field.]