relational database for mac

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: delete a prim number href work otherwise HTTP keywordBasic concepts: keywords, primary keywords, candidate keywords, non-keywords If the value of a field or multiple fields uniquely identifies a record, the field or field group is called a keyword .If a keyword is used to identify the uniqueness of each record and is associated with other table implementations, it is called the primary key (primary key, primary key), or the main code .A keyword other than the primary keyword is called a ca

Tags: databaseThe database system is one kind of software, the database system naturally also has his own life cycle--the lifetime. Its lifetime begins with planning, until it is uninstalled. Its intermediate process is very complex, in order to realize the user's idea, the database personnel will abstract the real life data, then in the classification and the op

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

Recently, a large number of new relational databases have sprung up in clouds outside the cloud. One of the key messages released here is: "If you want to get rich and on-demand scalability, you need a database that is not relational." ” If this is true, then is this not a sign that the once powerful relational

Basic concepts of one or two peopleNoSQL, which refers to non-relational databases.Relational database is a database based on the relational model.The relational model is mentioned here,The relational model was proposed by E.f.cod

An important part of designing a relational database is dividing the data elements into related tables. Once you're ready to start working with the data, you can rely on relationships between tables to aggregate the data in a meaningful way. For example, unless you know which customer placed a particular order, the order information is useless. So far, you may have realized that you did not store customer a

This section describes the theory of Relational Database Design Based on relational algebra. Function dependency is the basic part, and various paradigms are introduced in the constraints of Pattern Design and their coping problems. 3.1 function dependency The relationship design theory allows people to test and improve a design based on a few simple principles.

Introduction to 1.mongodbMongoDB (http://www.mongodb.org/) is a high performance, open source (the generation of Earthquake army Daniel is studying MongoDB source code, we can go to see http://www.cnblogs.com/daizhj/), Mode Freedom ( Schema-free) is a document-based database that can be used in many scenarios to replace traditional relational databases or key/value (Key-value) storage methods. MongoDB uses

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

Tags: differentiating CTC identity sel paradigm Problem _id Third paradigm RelationshipThe sixth chapter of relational data theory This chapter explains the relationship normalization theory in detail, which is not only the important theoretical foundation of relational database but also the powerful tool of database d

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

-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