relational database software

Label:Original: http://www.cnblogs.com/linjiqin/archive/2012/04/01/2428695.html In order to build a database with small redundancy and reasonable structure, we must follow certain rules when designing database. In a relational database, this rule is called a paradigm. A paradigm is a summary of a design requirement. In

Original link: http://coding-geek.com/how-databases-work/#Buffer-replacement_strategiesThe cache chapters are translated first, and the other chapters are translated later. Contents of translation in the original text:first, Data managerThe data query performs a query operation that fetches data from the data table and sends a request to data manger to get the information. There are 2 questions: Relational data uses a thing model that cannot

Tags: relational database Database system query optimization relationshipQuery optimizationHas a very important position in the relational database system.Relational query optimization is a key factor affecting RDBMS performanceBecause the semantic level of the

the projection operation, because once a particular column is selected, duplicate rows may be generated, and the duplicate rows must be eliminated3, connection.A connection that is a connection condition by one of the attributes in one relationship that is equal to a property of another relationship.Logical Database DesignTransforming entities and relationships into relational patternsFunction-dependentLos

wp_term_relationships classification relationship table, as shown in (this figure is from the Northwestern University WordPress source code interpretation team: Wp_term_relationships classification relational table -- WordPress Database The association between the wp_term_relationships classification table and other data tables: The wp_term_relationships classification relation table is associated with

The origin of the codd RDBMS12 rule--rdbms Edgar Frank Codd (Edgar Frank Code) was hailed as "the father of relational databases" and was awarded the Turing Prize in 1981 for his outstanding contribution to the theory and practice of the database management system. In 1985, Dr. Codd issued 12 rules that succinctly define the concept of a relational

apply it directly. I took this book in October this year, so I should practice it first. The previous video from instructor Yan jianling focuses on the specific operations in the database, there is not much to do with the necessary steps in database design, that is, the conversion from the conceptual model to the logical model. Enter the subject: Background: Data System survival The entire period from plan

Because of the needs of the work, need to transfer the data in HDFs to the relational database to become the corresponding table, on the Internet to find the relevant data for a long, found that different statements, the following is my own test process: To use Sqoop to achieve this need, first understand what Sqoop is. Sqoop is a tool used to transfer data from Hadoop and

I. First paradigmIn any relational database, the first paradigm (1NF) is the basic requirement for relational schemas, and a database that does not meet the first normal form (1NF) is not a relational database. The so-called First

Tags: Big Data eraSqoop as a Hadoop The bridge between the traditional database and the data import and export plays an important role. by expounding the basic grammar and function of Sqoop, the paper deeply decrypts the function and value of Sqoop. First, what is Apache Sqoop?Clouderadeveloped byApacheOpen Source project, isSql-to-hadoopthe abbreviation. Mainly used inHadoop (Hive)with the traditional database