db2 relational database

Document directory 4) Check Integrity Constraint rules-how to execute Integrity Constraint rules in actual operations Introduction to database application development-basic concepts in relational databases are written before: relational databases are currently the most widely used databases. Understanding the basic concepts of

Index Understand the related tables. FOREIGN key JOIN and maintain referential integrity For some suggestions on joins, subquery VS. Linked table Query I found that there is a tutorial in the MySQL documentation, but the concept does not seem to mention, just tell you how (statement), did not tell you the cause and consequences (principle). Want to see a book with vivid explanations, such as the one that will give the various joins the VN diagram, and do not know how to fin

DB2 database is one of the key projects supported by IBM and is widely used. The following describes how to use DB2 joint database for your reference. You can use an SQL statement to query data from multiple data sources using the DB2 federated

stage of the project (DBA is required for later optimization ). Based on the author's project experience, a developer proficient in OOP and ORM often designs more rational databases and better adapts to changes in requirements. if the reason is pursued, I guess it is because of database standardization, similar to some OO ideas (such as cohesion ). While DBA, the database designed has the advantage of bein

. The Minimum Redundancy must be achieved on the premise that the decomposed database can express all information of the original database. Its fundamental goal is to save storage space, avoid data inconsistency, improve the efficiency of relational operations, and meet application requirements. In fact, it is not necessarily required that all models reach bcnf.

After the concept of database was put forward, several data models appeared successively. There are three kinds of basic data models: Hierarchical model system, network model system, and relational model system. The relationship model proposed in the late 60 has the characteristics of simple and flexible data structure, easy to understand and strong mathematical foundation, and it has been popular since the

Tags: first paradigm sharp customer vanishing subset keyword cell problem processing log In order to establish a relatively small and reasonable relational database, we must follow certain rules when designing relational database, that is, the design paradigm of relational d

This paper mainly introduces the theoretical basis of relational database design which is closely related to the establishment of relational model (i.e. relational table structure), which is the basic knowledge of relational paradigm. The paradigm theory provides a theoretic

-written transaction log, which is written on the transaction log before committing the data to the actual data page. Four. Consistency Consistency means that the integrity constraints of a database are not compromised until the start of the transaction and after the transaction has ended. This means that database transactions do not break the integrity of relational