Databases database management systems and query languages a – mis – 204

Databases, Database Management Systems, and Query Languages A database is an organized collection–or list–of logically related data. Data recovery pro review A database management system (DBMS) is a program that is used to administer and access the data stored in a database. Data recovery windows 8 Often, people will conflate the two terms.

Data recovery devices For example, a lot of people refer to Microsoft’s Access program as a database when it is actually a database management system that accesses a database file. Moto g data recovery software A DBMS uses what is called a query language to access the data. Data recovery windows 10 A query language is similar to a computer programming language: It provides the syntax (rules) for accessing the data stored within the database. Database youtube Databases vs. H2 database console Lists Lists are useful when the data is simple and limited. Database browser For example, grocery lists and to-do lists are used all the time by people to keep track of important items and tasks. Database help When the data is complex and large, lists can become unwieldy. Database vendors Consider the following example: The Blue Cat Widget Company maintains in a file a list of its retail customers, the specific widget models that they stock, and the customer’s salesperson. Database key It looks like this: Figure 8.3. Data recovery live cd Big University List Example Business Name Customer First Name Customer Last Name Widget Part Number Widget Model Name Blue Cat Salesperson The Widget Outlet Steve Adamsmith 100 Cat Widget Tom Bombadil Widget Master Janie Fahayak 770 Universal Widget Eddard Stark The Retail Store Michelle Miltfriedman 1000 Z1000 Vladimir Harkonnen Figure 8.3. Data recovery clean room Blue Cat Widget Company List Example Each list entry is a composite of customer, model, and salesperson. Database view The problem is that when one of the elements changes, every list entry that has that element in it has to be updated. Data recovery fort lauderdale For example, if Part # 100 changes its name from “Cat Widget” to “Lion Widget”, every list entry

with a customer buying Part # 100 has to be manually updated. Data recovery equipment tools This is not a problem if there are 10 listed items, but if there are 100,000 entries, the task is much more labor intensive. Data recovery lab However, relational databases can solve this problem. Data recovery online Let’s look at how relational databases, tables, records and fields, and queries can help. Database union Relational Databases Today, most organizations use relational databases instead of lists. Data recovery houston A relational database breaks lists into entities , which are classes (categories) of objects, and relations , which are logical links between entities. 7m database soccer basketball In the Blue Cat Widget Company example, the entities would be customer, model, and salesperson. Create database link The relations would be customers purchase models and salespeople sell models . Database form By splitng up The elemenT This way and Then rela±ng Them, when a model name changes, all you have To do is updaTe The model lisT. Data recovery process Any cusTomers relaTed To ThaT model will see The change auToma±cally. Database training Tables, Records, and Fields Without getting too deep into the technology weeds, it is important to understand the components of a database . Data recovery hardware The fundamental component of a database is the table. Best database software A table represents an entity.