relational database software

(1nf) means that each column in the database table is an inseparable basic data item, that is, an attribute in the entity cannot have multiple values or duplicate attributes. In any relational database, the first paradigm (1nf) is the basic requirement for the relational model. databases that do not meet the first par

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

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.

The next step is to explain each level of the paradigm, firstThe first paradigm (1NF). Conforms to the 1NF relationship (you can understand it as a data table.) The difference between "relationship" and "relationship pattern" is similar to the difference between "class" and "Object" in object-oriented programming. "Relationship" is an example of "relational pattern", you can understand "relationship" as a table with data, and "

stored procedure Store function trigger Event SchedulerConstraints:Domain constraints: Data type constraintsFOREIGN KEY constraints: referential integrity constraintsPRIMARY KEY constraint: A field can uniquely represent the entity to which this field belongs, and is not allowed to be emptyA table can have only one primary keyUnique key constraint: A field in each row is not allowed to have the same value, can be emptyA table can have more than one unique keyCheck constraint: Age:intConstraintT

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

Nowadays, the BigTable (column family) database is used more and more widely, and the function is very powerful. But many people still regard it as a relational database in use, with the original relational database thinking to build tables, storage, query. This article take

Eloquent ORM (Object relational mapping) ORM, the Object-relational Mapping (Object relational mapping), is a mapping between relational databases and business entity objects, so that we don't have to deal with complex SQL statements when we're working with specific business objects. Simply manipulate the properties an

Label:androidsqlitesqliteopenhelpersqlitedatabase cursor SQLite--Embedded relational database 1,sqlite data type: typelessness (no type) 1, you can save any type of data to any column in the table 2, support common types such as: NULL, VARCHAR, TEXT, INTEGER, B LOB, CLOB etc 3, the only exception: integer primary key This field can store only 64-bit integers, that is, only 64-bit integers can be stored when

Tags: des blog http using strong dataI believe that the development experience of friends have encountered such a demand. Suppose you are developing a comment function for a news site, and readers can comment on the original text or even reply to each other.This need is not simple, mutual reply will lead to an infinite number of branches, an infinite number of ancestor-descendant relationships. This is a typical recursive relational data.For this prob

Label:Objective On a relational database commonly used SQL statement syntax is mainly relational database general structure, this paper discusses the relational database query SQL syntax. Grammar Review

-sized enterprises. The experimental case is written by Luca Sinico (infocamere software developer) Experiment OverviewInfocamere in the second half of 2016 to carry out the field of graphic database inspection, the purpose of the work is to investigate the main characteristics of the technology; Compare some of the available products and relational sol