relational database advantages and disadvantages

Label:DirectoryThe origin of a Codd RDBMS12 law--rdbms Design phase of two-relational database Three design principles Four naming rules Database design, a cornerstone of the success of a software project. Many practitioners agree that database design is not really that important. The reality of the scene is quite simi

Label:Transferred from: http://www.cnblogs.com/MeteorSeed/archive/2013/03/27/2880054.html ------------------------------------------------------------------------------------- Directory The origin of a Codd RDBMS12 law--rdbms Design phase of two-relational database Three design principles Four naming rules Database design, a cornerstone of the success of a softwa

-to-many relationship, and if you combine score into a student table, you must reserve the most possible fields, which can be wasteful and will be difficult to expand when you add a new course later , so the score table is generally separated out. And for Key-value type database is different, its scores field is a Bson, the Bson can have only one for_course, can also have two, three, any for_course, Its inherent pattern-free nature makes it possible t

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

decomposition method is used to eliminate exceptions. An unreasonable relationship is broken down into multiple rational relationships. 3.3.2 bcnf paradigm If R belongs to bcnf and is only used: the left side of the extraordinary FD of R is a superkey. If R's non-trivial fd x-> Y is formal, X is the Super key of R. 3.3.3 bcnf decomposition algorithm Input: relational R0 and function dependencies on it F0 Output: a set of links decomposed by R0. Each

Standardization | design | data | database | Database design relational database design is the process of organizing and structuring data. The core problem is the design of the relational model. A relational model is a mathematic

Label:The disadvantages of relational databases: with the rise of Internet web2.0 Web site, the traditional relational database in dealing with web2.0 website, especially the super-large-scale and high-concurrency SNS type web2.0 pure dynamic website has appeared to be inadequate, exposing a lot of difficult problems t

customer/Server structure, applications are run on multiple machines. One machine is the customer of another system or the server of another machine. These machines are connected through the LAN or WAN. advantages of the customer/server model: it supports resource sharing and load balancing among multiple devices, allowing the environment to accommodate multiple hosts, make full use of the existing systems of the enterprise (2) It is a truly open

completed, different link modes can be obtained. That is to say, the decomposition method is not unique. The Minimum Redundancy must be achieved on the premise that the decomposed database can express the confidence of the original database. Its fundamental goal is to save storage space, avoid data inconsistency, improve the efficiency of relational operations,

)　　Inserting a node can also be as simple as using an adjacency table. You can insert a leaf node without modifying any of the other rows. All you need to do is copy a logical Father node path to the node to be inserted and append the ID of the new node to the end of the path. If this ID is generated by the database when it is inserted, you may need to insert this record first, then get the ID of the record and update its path.　　

Source: http://www.cnblogs.com/chay1227/archive/2013/03/17/2964020.htmlThe relational database represents all of the data through the two-dollar representation of rows and columns.The benefits of a relational database:1. Maintain data consistency (transaction processing)2. Due to standardization, the cost of updating d

table have a column for the department ID, which allows the database to answer the question: What is the department name of the department where the employee works?The advantages of the relationship type More flexible than other types Allows business logic to quickly accept conditional changes Data-driven vs application-driven Modular business, not process Makes it easier to build

primary key and consists of one or more columns. Link mode: describes a link. The format is: Link name (attribute 1, attribute 2 ,..., Attribute N ). A database is usually called a table structure. 2. Advantages of relational databases Compared with databases of other models, relational databases have the following

as using an adjacency table. You can insert a leaf node without modifying any of the other rows. All you need to do is copy a logical Father node path to the node to be inserted and append the ID of the new node to the end of the path. If this ID is generated by the database when it is inserted, you may need to insert this record first, then get the ID of the record and update its path.　　Disadvantages of P

Abstract Yes: Workflow technology is one of the core technologies in office automation systems. Based on the features of the workflow in document flow, this paper analyzes the document flow data model established in the relational database, and provides the implementation method of the Document Flow System Based on this data model. 1. Introduction Office automation is a new office method that combines moder

Label:There are two kinds of database design models widely used in Data warehouse: Relational type and multidimensional type. It is generally believed that the relational model in the design method of Data Warehouse is "Inmon" method and multidimensional model is "Kimball" method. First look at the relational model, wh

compared to relational database, the advantages of MongoDB: reprinted from Http://blog.sina.com.cn/s/blog_966e430001019s8v.html① Weak consistency (eventually consistent), to ensure the user's access speed:For example, in a traditional relational database, a count type of ope

. Identifiers based on existence have the advantage of being a separate property, with a small placeholder and the same size. As long as your relational database management system (RDBMS) is supported, there is no performance disadvantage based on existing identifiers. (most RDBMS provide a valid allocation order number based on an existing identifier.) The only disadvantage is that identifiers based on exi