simple relational database

system was then produced in the late 60. The data of database system management is structured, which provides powerful data query function and provides good data sharing. At that time, the database system mostly uses the hierarchical data model or the network data model. With the development of data management technology, in the early 70, the relational data th

Advantages and disadvantages of relational databaseAdvantages: Can do transaction processing, so as to ensure the consistency of data; Can be a join, such as multi-table query; Because of SQL standardization, the cost of data updates is small (the same fields are basically only one place). Disadvantages: The write processing of large amount of data is not easy; If the table data volume is too large, it is not easy to do index or

Data | Database It's the father of the database. 12 recommendations for implementing a relational database management system: Codd ' s Rules Dr. E.f. Codd, an IBM researcher, the developed of the relational data model in 1970. In 1985, Dr. Codd published a list of rules th

. The field types are text, date/time, Number, dialog box list, check box, radio button, list box, combo box, Rich text, author, name, reader, password, and formula. The primary properties of the domain are: Editable: Data can be generated by using a button to execute a formula (formulas) or script (scripts). Implied: only for storage, not for display, the data for the field is not displayed when the document is displayed. Quasi many values: A single domain allows users to deposit multiple va

"name" as two fields). Therefore, we should also consider whether or not to cut attributes when designing. (ix) Normalization-paradigm When I am still in college, Paradigm is the most headache when learning relational database. I think there may be readers who still do not understand the value of the paradigm, simply speaking-the paradigm will help us to ensure the validity and completeness of the data. Th

Label:The concept of relational databases The database established by the relational model is the relational database (relational Data Base,rdb), and the DBMS of relational

should also consider whether or not to cut attributes when designing. (ix) Normalization-paradigm When I am still in college, Paradigm is the most headache when learning relational database. I think there may be readers who still do not understand the value of the paradigm, simply speaking-the paradigm will help us to ensure the validity and completeness of the data. The purpose of normalization is as foll

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

Label: MongoDb compared to the traditional SQL relational database, the biggest difference lies in their schema design (schema) differences, it is because this level of differences derived from other aspects of the difference. we can simply think that the relational databaseconsists of three hierarchical concepts of database