logical database design

) Fax This should be the easiest way of thinking, simple and clear. For example, if you want to query the contact information of a person, you can use only one statement: Select Name, Telphone, Email, Fax from table where Condition During the query, the database design is very clear and there is no difficulty in thinking and no logical challenge. However

The Oracle tutorial you are looking at is: talking about the modeling and design of Oracle database. To develop a database based application system, one of the most critical step is the whole system based on the database modeling design, from the

The structure of a database (such as tables, relationships, views, and triggers) is called a database schema . You can use SQL statements to create these elements and arrange them in the way you want, but it can be confusing if you don't use graphical tools. PowerDesigner provides a graphical representation of the structure of a database. You can better modify th

My first python web development framework (4) -- database structure design and creation, and python Structure Design After finishing the front-end html design, Tom immediately began to design the database structure. 　　 Before he s

relationships. So its data structure is simple, clear, user-friendly access path transparent: With higher data independence, better security confidentiality, simplifying the programmer's work, improve the software development and maintenance efficiency The main disadvantages are: Because the access path is transparent to the user, the query efficiency is often inferior to the non relational data model in order to improve the performance, the DBMS must query and optimize the user's quer

Tags: performance selection memcached style HTTP under Good information fetch numberWhen you design a database, a field belongs to one table, but it appears in the other or more tables at the same time, and is exactly the same as the meaning of the table it belongs to, then this field is a redundant field. --These are the definitions I gave myself. Is the existence of redundant fields good or bad ( Redunda

3 efficient Tags tag system database design solutions, tags design solutions Background Currently, mainstream blog systems and CMS all have a TAG Tag system, which not only enhances the structure of content links, but also allows articles to be distinguished by tags. Compared with the traditional Keyword mode, this Tag mode can independently

The structure of a database (such as tables, relationships, views, and triggers) is called a database Mode。 You can use SQL statements to create these elements and arrange them in the way you want, but it can be confusing if you don't use graphical tools. PowerDesigner provides a graphical representation of the structure of a database. You can better modify the s

Data Center reconstruction-database design, data center reconstruction Database Database Design-conceptual design stage This phase mainly draws an erdiagram based on requirements, as shown in the following figure. The diagram sh

practice of database management systems. In 1985, Dr. Codd released 12 rules that clearly define the concept of a relational database as a guiding principle for the design of all relational database systems. Information Rules all information in a relational database is re

Part 2-Design tables and fields1. Check for various changesWhen designing a database, I will consider which data fields may change in the future. For example, the last name is like this (noteIt refers to the surname of a westerners, for example, the surname of a female after marriage ). Therefore, when establishing a system to store customer information, I tendStore the Last Name field in a separate data ta

Sun Blueprint Adventure Builder Database design Catalogue 1 preface .... 1 1.1 Background ... 1 1.2 Writing motivation and style ... 2 1.3 Selection of database design methods ... 2 1.4 who is suitable to read this article. ... 2 1.5 Terminology and abbreviations ... 2 2 Adventure Builder Introduction .... 3 3

these patterns are appropriate for your application environment, and determine whether you want to merge or decompose them. Perform necessary decomposition or merging of relational schemas To design a user sub-mode: Use aliases that are more user-compliant Different external modes are defined for different levels of users to meet the security requirements of the system. Simplifies user use of the system Task: T

department2, the domain can be a module, can be a page, or it can be a button on the page3, the permission can be "visible", can be "read-only" or "available" (such as a button can be clicked)is actually the WHO, what, how problemSo the six tables mentioned above can actually design a table:IV, example descriptionHere is an example of a design description. "User, role on page is permission to use"Detailed

Label:Design of questionnaire module of database design 1 2016/07/13 Update The entire internship has come to an end, in fact, the entire Questionnaire module database design, in early June basically has been finalized and realized. This summary is divided into two parts. One, to the previous proposed a few legacy issu

span each hard disk controller, and vertical bars span the entire hard disk set. The number of members in the set should not be greater than the number of hard disk controllers. For OLTP applications, the data access volume is small. Generally, the size of 32 kb or 64 kB entries can be selected, while the DSS application accesses a large amount of data, you can consider the size of a 64KB, 128KB, or 256KB shard. Application database

. Conceptual Structure Design Stage In the conceptual structure design phase, the results of requirement analysis are converted into a separate stage (the stage starts the substantive stage of database integrity design, because the physical relationships in this phase will be converted into Entity integrity constraints

Seventh Chapter Database DesignDatabase design is to construct (design) optimized database logical mode and physical structure for a given application environment, and establish database and its application system so that it can s

contain additional business logic. (4) In the rule 4:mysql, ll_create, ll_modified use datetime types. (5) Rule 5: Prohibit the use of complex data types (arrays, custom types, etc.). (6) In rule 6:mysql, the satellite table ID is consistent with the primary table ID when the subordinate table is split. New primary key fields are not allowed in the satellite table. (7) In the rule 7:mysql, the table with outdated concept must have the expiration mechanism at the beginning of its

Time: Location: Base -------------------------------------------------------------------------- building a database application is a very complex task, including a database design mode, design the program for accessing and updating data, and design the Security Mode for cont