logical database design

button on the page 3, the permission can be "visible", can be "read-only" or "Available " ( such as a button can be clicked ) is actually the WHO, what, how problem So the six tables mentioned above can actually design a table: IV, example description Here is an example of a design description. "User, role on page is permission to use" Detailed design: 1,

department 2, the domain can be a module, can be a page, or it can be a button on the page 3, the permission can be "visible", can be "read-only" or "Available " ( such as a button can be clicked ) is actually the WHO, what, how problem So the six tables mentioned above can actually design a table: IV, example description Here is an example of a design description. "User, role on page is permission t

,creating/reading/updating/deleting). This type is more officially called "OLTP". Analytic type: This type of application, your end user more attention to data analysis, reports, trend prediction and so on functions. The "Insert" and "Update" operations of this type of database are relatively small. Their main purpose is to query and analyze data more quickly. The more official term for this type is "OLAP". So in other words, if you think inserting,

, manage, control, and distribute data/information across the company.Inheritance (inheritance): See Attribute Inheritance (Attribute inheritance).Integrity constaints (integrity constraint): A constraint that prevents inconsistent data in the database.Is-a hierarchy (Is-a hierarchy): The same type hierarchy (type hierarchy).The local logical data model, the local logical data model, represents a combinatio

a primary key(because it has no descendants), but must have a foreign key (because it has a father).The design of primary key and foreign key plays an important role in the design of global database. When the global database design is complete, there is an American

fields in the database table are all single attributes, no further {personal understanding: like a family, there are several sons, the other sons are made up of one part, but a son needs two parts, that is, this is not a normal family, hehe, said too much}. This single attribute consists of a basic type, including Integer, real, character, logical, date, and so on. For example, for example, the following

[Study notes] database design overview bitsCN.com ReferencesDatabase design-Conceptual Design, Logical Design, Physical DesignConceptual ~ Logical ~ Physical Models

If these two conditions are met, it can be explained that the standard of the database is still relatively high. Of course, this is a two-generalities indicator. In order to meet the requirements of database design normalization, the following five requirements are generally required. Request One: Nullable columns should be avoided in the table. Although emp

areas:Storage spaceImpact on the performance of the current operating systemImpact of recovery timeIf you need to save space and restore time, you need to increase the frequency of backups, but the backup operation will significantly increase the load on the currently running system. 、Oracle's recovery approachDifferent methods of recovery are used according to different backup methods.Using physical backup to restoreOracle offers three ways to recover:1, d