Database Fundamentals

Database Fundamentals

• A database is an organized collection of data.
• A database management system (DBMS) is a group of programs that manipulate the database and provide an interface between the database and its users and other application programs.

Database Concepts

• An entity is a person, place, or thing for which data is collected, stored, and maintained.
• An attribute is a characteristic of an entity.
• A data item is the specific value of an attribute.

Data Modeling

• A data model is a diagram of data entities and their relationships.
• Entity-relationship (ER) diagrams are data models that use basic graphical symbols to show the organization of and relationships between data.

Relational Database Model

• The relational database model is a useful way to organize data into a collection of two-dimensional tables called relations.
• A primary key is a field or set of fields that uniquely identifies the record.

Database Operations

• Selecting involves eliminating rows according to certain criteria.
• Projecting involves eliminating columns in a table.
• Data cleaning or data scrubbing is the process of detecting and then correcting or deleting incomplete, incorrect, inaccurate, or irrelevant records that reside in a database.

Database Languages

• SQL (Structured Query Language) is a special-purpose programming language for accessing and manipulating data stored in a relational database.

Database Administration

• A data administrator is a nontechnical position responsible for defining and implementing consistent principles for a variety of data issues.
• The data administrator sets data standards and data definitions that apply across all the databases in an organization.

Database Services

• Database as a Service (DaaS) is a service where the database is stored on a service provider's servers, and accessed by the client over a network, typically the Internet.

Data Warehousing

• A data warehouse is a large database that collects business information from many sources in the enterprise in support of management decision making.
• A data mart is a subset of a data warehouse that is used by small- and medium-sized businesses and departments within large companies to support decision making.

NoSQL Database

• A NoSQL database provides a means to store and retrieve data that is modeled using some means other than the simple two-dimensional tabular relations used in relational databases.