Terminology

Data

Data is a collection of a distinct small unit of information.

Database

The database is a collection of inter-related data which is used to retrieve, insert, update and delete the data efficiently. It is also used to organize the data in the form of a table, schema, views, and reports, etc. For example, the employee database organizes the data about the employee, department, etc.

Table

A structured set of data elements, organized in rows and columns. Tables are the primary structure in a relational database.

Row

Also known as a record, it represents a single, complete set of related data in a table.

Column

Also known as a field, it represents a single attribute of data in a table.

Primary Key

A column or set of columns that uniquely identifies each row in a table. It ensures data integrity and provides a way to reference individual records.

Foreign Key

A column or set of columns in one table that references the primary key in another table. It establishes a relationship between the two tables.

Index

An optional structure associated with a table to improve the speed of data retrieval. Indexes are created on columns to quickly locate rows in a table.

Query

A request for data or information from a database. SQL queries are used to retrieve, insert, update, or delete data from tables

Normalization

A process of organizing data in a database to reduce redundancy and dependency. It involves dividing large tables into smaller, related tables and defining relationships between them.

Transaction

A single unit of work performed within a database management system. It can consist of one or more SQL statements that are executed as a single operation.

View

A virtual table generated from the result of a SQL query. Views do not store data themselves but provide a way to present data stored in tables in a customized format.

Stored Procedure

A pre-compiled collection of SQL statements that are stored and executed on the database server. Stored procedures can accept input parameters and return multiple values.

Trigger

A special type of stored procedure that is automatically executed or fired in response to specific events, such as data manipulation (insert, update, delete) on a table.

Clauses

Components within a statement that define specific actions (e.g., SELECT clause in a SELECT statement).

Operator

A special keyword used to join or change clauses within a WHERE clause. Also known as logical operators. Eg. OR, AND, IN etc

Degree

Represents the number of columns in a table. It indicates the complexity of each record (row) in the table. A higher degree (more columns) can provide richer data but also increases storage requirements and complexity of managing the data. Example: A Customers table with columns for CustomerID, FirstName, LastName, Email, and PhoneNumber has a degree of 5.

Cardinality

Represents the number of rows in a table. It indicates the overall size or volume of data stored in the table. A higher cardinality (more rows) can lead to larger storage needs and potentially slower query performance for retrieving data. Example: A Customers table with information for 1000 customers has a cardinality of 1000.