postgresql database design tool

sometimes in order to improve operational efficiency, it is necessary to lower the paradigm standard and properly retain redundant data. The practice is to adhere to the third paradigm when designing the conceptual data model, and to lower the standard of normalization into the design of the physical data model. Lowering the paradigm is adding fields, allowing redundancy.6. Be good at identifying and correctly dealing with many-to-many relationshipsT

perfunctory bad habits, on the other hand also in the data storage waste a lot of space, because using the default field length often occurs on a field. (4), do not use Unicode text fields easily The DBMS support for Unicode helps to internationalize the product while also contributing to a certain amount of wasted space, especially when the text to be stored is essentially ASCII character, this waste is particularly noticeable. Therefore, it is suggested that the reason for the designer to c

access to the company will use this UML Tools Oh. 1 Create Design ModelPhysical Data:Note Select the type of database: then click OK2New FormTable:3To set a field:Check the primary key tick p ( primary key primary key), m means non-empty, set directly click OK 4To create a foreign key:manually modifying foreign keysClick the Reference button to select from the table, point to the main table; But th

adhere to the third paradigm when designing the conceptual data model, and to lower the standard of normalization into the design of the physical data model. Lowering the paradigm is adding fields, allowing redundancy.6. Be good at identifying and correctly dealing with many-to-many relationshipsThis relationship should be eliminated if there is a many-to-many relationship between the two entities. The solution is to add a third entity between the tw

results, and sometimes it has no primary key and Foreign key (except Data Warehouse). Temporary tables are designed by programmers to store temporary records that are used by individuals. The base table and the intermediate table are made up of the DBA dimension and temporary tables are automatically maintained by the programmer using the program itself. 12. Integrity constraints are represented in three areasDomain Integrity: Use Check to implement constraints, in the

physical data model (PDM file), we need to define a project's data field fields, the definition of field has one advantage is that when designing a datasheet later, the type of field can be chosen with the type defined in the field. Changed the type information for the field, and the field information associated with the field reference in the table changes accordingly, which facilitates the modification of the field and also unifies the field type and length. Once you have defined the fields,

correctly dealing with many-to-many relationships 　　 This relationship should be eliminated if there is a many-to-many relationship between the two entities. The solution is to add a third entity between the two. Suchoriginally a many-to-many relationship, now becomes two one-to-many relationship. To properly assign the original two entity's attributes to three entities. The third entity here is essentially a more complex relationship that corresponds to a basic table. Generally speaking, the

Label:1. Requirements Description: After the software development is completed, the delivery customer usually needs the database design document before the customer uses, many programmers even the project manager naturally thought to adopt human sea tactics, a project group member, sub-module to write, then merges. As programmers, this approach is too low. So can there be automated tools, of course, with de