best relational database

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

The relational database paradigm must follow certain rules to construct a database. In relational databases, this rule is a paradigm. A paradigm is a set of relational patterns at a certain level. The relationships in relational d

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

Relational database technology is mature, widely used, support tools rich and powerful, data storage, query efficiency, so when the semantic data storage is not mature, no effective tools appear, it is widely used in ontology data storage. Because of the difference between ontology model and relational model, ontology storage based on

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

connection, which requires that the property names in the two relationships be compared, and that duplicate columns are dropped in the result Some tuples in the relationship R do not exist in the corresponding S, so it is possible to be discarded and become suspended tuples (Dangline tuple) The suspension tuple is reserved and null is filled in as an outer join. Leave left and right respectively left connected rightExcept operationsR/S ={tr[x] | Tr belongs to R and Πy (S) belongs to YX}

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.

Scenarios where relational databases cannot be used-reproduced:10 cases where the relational database is not available: things never to do with a relational db | Application Development-infoworld may be able to play a role in the direction of ordinary people.Translation of the main effect is as follows:1. Search: Even

Relational Database Terms and Definitions 1. Key: it is an important concept in a relational model. It is used to identify one or more columns of a row in a relational model. 2. Candidate Key: it is an attribute set that uniquely identifies a row in a table and does not contain any redundant attributes. That is, i

Infi-chu:http://www.cnblogs.com/Infi-chu/relational databaseRelational database is a database based on relational model, and the relational model is saved by a two-dimensional table, so the storage of relational

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: 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

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

1.1.1 What is relational dataRelational data is data that is represented by a relational mathematical model. The relational mathematical model describes the data in the form of a two-dimensional table, as shown in tables 1.1 and 1.2.1.1.2 What is a relational database1. What is the main code (primary key)A combination

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: key codis decision IMG Native transaction mechanism mongod contrast algorithmThe famous open source distributed cache service Codis's author, Pingcap co-founder CTO, Senior Infrastructure engineer Huangdongxu, specializes in the design and implementation of distributed storage systems, the technology of open source fanatics, the great deity level figures. Even today, when the Internet is so prosperous, in the vague and uncertain boundaries of the data