Chapter 3 Data Management

In-store sales

Data on sales that occur in physical store locations.

Catalog content

Information about products available in catalogs.

Operational Database

A live database that supports real-time transactions.

Offline Database

A database used for reporting and analysis, separate from real-time operations.

SQL (Structured Query Language)

A data sublanguage designed for creating and processing database data and metadata.

Data Definition Language (DDL)

SQL statements used for creating database structures, such as tables and relationships.

Data Manipulation Language (DML)

SQL statements used for inserting, querying, modifying, and deleting data.

Transaction Control Language (TCL)

SQL statements used for managing transactions that execute groups of SQL operations together.

Data Control Language (DCL)

SQL statements for granting or revoking access permissions for users.

SELECT Statement

The core SQL query structure that retrieves data from a database.

DISTINCT keyword

Used to remove duplicate rows from the result set.

TOP function

Controls the number of rows returned in a query.

WHERE clause

A clause that filters records based on specified conditions.

GROUP BY clause

A clause that groups data based on specified column(s).

HAVING clause

A clause that filters grouped results, used with aggregate functions.

LIKE operator

Allows pattern matching in SQL queries.

Wildcard character (%)

Represents any sequence of characters in SQL queries.

Aggregate Functions

Functions that perform a calculation on a set of values and return a single value.

Difference between WHERE and HAVING

WHERE filters individual rows before grouping; HAVING filters groups after aggregation.