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DataBase and DBMS. Introduction Cheat Sheet by

DataBase and DBMS. Main Tips

Inform­ation and Data

Inform­ation refers to processed and organized data that provides context, meaning, and value
Data refers to raw and unproc­essed facts and figures
Inform­ation is presented in a structured and meaningful way that can be easily understood and used
Data is typically repres­ented in the form of numbers, text, or symbols
Inform­ation is data that has been processed, analyzed, and interp­reted to provide context and meaning. It answers specific questions, addresses a particular problem, or supports decisi­on-­making.
Data is the raw material that is used to derive inform­ation. Inform­ation, on the other hand, is used to gain insights, make informed decisions, or commun­icate knowledge.
Inform­ation is considered valuable as it provides insights, knowledge, or answers to specific queries. Data, in its raw form, has minimal value until it is processed and transf­ormed into meaningful inform­ation.

DataBase Models

High Level
Entity­-Re­lat­ionship Model (ER Model) represents entities, attrib­utes, and relati­onships between entities using entities, attrib­utes, and relati­ons­hips. Helps visualize the database structure and define the relati­onships between different entities.
Repres­ent­ational Level
is used to represent only the logical part of the database and does not represent the physical structure of the database. The repres­ent­ational data model allows us to focus primarily, on the design part of the database.
Low Level
The physical Data Model is used to practi­cally implement Relational Data Model. Ultima­tely, all data in a database is stored physically on a secondary storage device . Developed for a specific version of a DBMS, location, data storage or technology to be used in the project.
 

Repres­ent­ational Models

Hierar­chical Model
Organizes data in a tree-like structure with a parent­-child relati­onship. Each parent can have multiple children, but each child has only one parent.
Network Model
Extends the hierar­chical model by allowing each child to have multiple parents. Uses a graph-like structure to represent complex relati­ons­hips.
Relational Model
Describes data in terms of tables, where each table represents an entity or relati­onship. Utilizes primary keys and foreign keys to establish relati­onships between tables.
NoSQL Models
Document Model. Key-Value Model. Graph Model. Column­-family DB Model

SQL

Structured Query Language
is a standard language for storing, manipu­lating and retrieving data in databases

DBMS Archit­ecture

1 Tier Arch. - the client, server, and Database all reside on the same machine.
2 Tier Arch. - the presen­tation layer runs on a client, and data is stored on a server called the second tier.
3 Tier Arch. - the develo­pment and mainte­nance of functional processes, logic, data access, data storage, and user interface is done indepe­ndently as separate modules.
 

Repres­ent­ational Models

A database management system (DBMS)

is a comput­erized data-k­eeping system. Users of the system are given facilities to perform several kinds of operations on such a system for either manipu­lation of the data in the database or the management of the database structure itself
           
 

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