Relational database

The Computer Revolution/Databases/Database Models Hierarchical Databases[edit] Hierarchical databases are the oldest database models. Unlike other models, they do not have a well documented history. The hierarchical database was the first one developed and therefore was commonly used in the first mainframe database management systems.They were developed out of the 1950's and 60's Information Management Systems. Many banks and insurance companies, as well as government departments and hospitals ( for inventory and accounting systems) still use them today. The hierarchical database stores data in a series of records. As an example, we could have a tree representing a university department, with subtrees representing staff members, students, courses, and facilities. A hierarchical database has a very structured form, as it allows no links between layers in different branches of the tree. Advantages of the Database[edit] Shortcomings of the Database[edit] Currently this type of database is not utilized to its full potential. 1. 2. 3. 4. 5.

List of relational database management systems From Wikipedia, the free encyclopedia This is a list of relational database management systems. List of Software[edit] Historical[edit] Relational by the Date-Darwen-Pascal Model[edit] Current[edit] Obsolete[edit] See also[edit] What are relational databases?" Databases have been a staple of business computing from the very beginning of the digital era. In fact, the relational database was born in 1970 when E.F. Codd, a researcher at IBM, wrote a paper outlining the process. Since then, relational databases have grown in popularity to become the standard. Originally, databases were flat. This means that the information was stored in one long text file, called a tab delimited file. Lname, FName, Age, Salary|Smith, John, 35, $280|Doe, Jane, 28, $325|Brown, Scott, 41, $265|Howard, Shemp, 48, $359|Taylor, Tom, 22, $250 You can see that you have to search sequentially through the entire file to gather related information, such as age or salary. With a relational database, you can quickly compare information because of the arrangement of data in columns. The "relational" part of the name comes into play because of mathmatical relations. Here are some interesting links:

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Choosing a Database Oracle, SQL Server, Microsoft Access, MySQL, DB2, Paradox. There are quite a variety of database products on the market today, making the selection of a platform for your organization's infrastructure a daunting project. Define Your Requirements Database management systems (or DBMSs) can be divided into two categories -- desktop databases and server databases. Generally speaking, desktop databases are oriented toward single-user applications and reside on standard personal computers (hence the term desktop). Server databases contain mechanisms to ensure the reliability and consistency of data and are geared toward multi-user applications. It's important to do a careful needs analysis before you dive in and commit to a database solution. The needs analysis process will be specific to your organization but, at a minimum, should answer the following questions: Who will be using the database and what tasks will they perform? Desktop Databases Server Databases Flexibility.

PostgreSQL: The world's most advanced open source database Home The Department for Education's register of educational establishments in England and Wales. Using the search box below select school type and location to quickly find establishments in your local area or use the advanced search page for further search criteria including establishments that are closed or planned to open in the future. From this page you are able to perform a simple search of all open establishments in England and Wales. If you leave a field blank, the default will include all establishments. The 'Show me' drop down list allows you to select the type of establishment you wish to see in your search results. You have the ability to search by location, and can set a radius of inclusion. When searching by establishment name, often it is best to search for a single word in a name. Church of England is generally referred to as CofE in EduBase. For more advanced searches, or to find closed schools, please use the Advanced search page Contacting EduBase Disclaimer

Welcome to MariaDB! - MariaDB Ten Common Database Design Mistakes No list of mistakes is ever going to be exhaustive. People (myself included) do a lot of really stupid things, at times, in the name of “getting it done.” This list simply reflects the database design mistakes that are currently on my mind, or in some cases, constantly on my mind. I have done this topic two times before. Before I start with the list, let me be honest for a minute. So, the list: Poor design/planning Ignoring normalization Poor naming standards Lack of documentation One table to hold all domain values Using identity/guid columns as your only key Not using SQL facilities to protect data integrity Not using stored procedures to access data Trying to build generic objects Lack of testing Poor design/planning “If you don’t know where you are going, any road will take you there” – George Harrison Prophetic words for all parts of life and a description of the type of issues that plague many projects these days. Ignoring Normalization Are there always 12 payments? Maintainability

SQLite Home Page What is database Main » TERM » D » By Vangie Beal (1) Often abbreviated DB, a database is basically a collection of information organized in such a way that a computer program can quickly select desired pieces of data. You can think of a database as an electronic filing system. Traditional databases are organized by fields, records, and files. An alternative concept in database design is known as Hypertext. To access information from a database, you need a database management system (DBMS). (2) Increasingly, the term database is used as shorthand for database management system.

Mike Hillyer's Personal Webspace - Managing Hierarchical Data in MySQL Introduction Most users at one time or another have dealt with hierarchical data in a SQL database and no doubt learned that the management of hierarchical data is not what a relational database is intended for. The tables of a relational database are not hierarchical (like XML), but are simply a flat list. For our purposes, hierarchical data is a collection of data where each item has a single parent and zero or more children (with the exception of the root item, which has no parent). These categories form a hierarchy in much the same way as the other examples cited above. The Adjacency List Model Typically the example categories shown above will be stored in a table like the following (I’m including full CREATE and INSERT statements so you can follow along): In the adjacency list model, each item in the table contains a pointer to its parent. Retrieving a Full Tree Finding all the Leaf Nodes We can find all the leaf nodes in our tree (those with no children) by using a LEFT JOIN query:

Adjacency list vs. nested sets: PostgreSQL This series of articles is inspired by numerous questions asked on the site and on Stack Overflow. What is better to store hierarchical data: nested sets model or adjacency list (parent-child) model? First, let's explain what all this means. Adjacency list Hierarchical relations (not to be confused with hierarchical data model) are 0-1:0-N transitive relations between entities of same domain. For instance, ancestor-descendant relation is: Transitive: If A is an ancestor of B and B is an ancestor of C, then A is an ancestor of CIrreflexive: If A is an ancestor of B, then B is never an ancestor of A0-1:0-NA can have zero, one or many children. These relations can be represented by an ordered directed tree. Tree is a simple directed graph (that with at most one directed edge between two different vertices) and relational model has means to represent simple graphs. Adjacency lists can represent any simple directed graphs, not ony hierarchy trees. The most common operations are: Nested sets 01. 02.