D426 Data Management Foundations - Set 1 - Part 3

Correct Answer: BETWEEN

The BETWEEN operator is used to compare a value to a range of values, specifying a minimum and maximum value in a query.

Correct Answer: COUNT()

The COUNT() function returns the number of rows in a result set, often used to determine how many rows meet certain criteria.

Correct Answer: To ensure that a column has unique values

A Unique Key ensures that all values in a specified column or set of columns are distinct, preventing duplicate entries.

Correct Answer: AVG()

The AVG() function calculates the arithmetic mean (average) of the values in a specified column.

Correct Answer: A real-world object or concept represented in a table

An entity represents a real-world object, person, or concept in a relational database, typically modeled as a table with attributes.

Correct Answer: UPDATE

The UPDATE statement is used to modify the values of existing rows in a table, typically by specifying new values for certain columns.

Correct Answer: LIKE

The LIKE operator is used in SQL to filter rows based on matching patterns in a text field, often used with wildcards like % and _.

Correct Answer: Primary Key

A Primary Key is used to uniquely identify each row in a table and must contain unique, non-null values to ensure data integrity.

Correct Answer: LEFT JOIN

A LEFT JOIN returns all rows from the left table and matching rows from the right table, filling in NULL values where there is no match.

Correct Answer: Referential Integrity

Referential Integrity ensures that foreign key values in a table must either match an existing primary key value or be NULL, maintaining relationships between tables.