Mastering ER Diagrams and SQL

What does ER stand for in ER diagrams?

• Entity-Record

• Entity-Relation

• Entity-Reference

• Entity-Relationship

What is the primary purpose of an ER diagram?

• To represent the relationships between entities in a database.

• To optimize the performance of queries.

• To create a backup of the database.

• To display the data in a tabular format.

Define DDL and give an example of a DDL command.

• SELECT * FROM

• CREATE TABLE

• ALTER VIEW

• DROP DATABASE

What is the difference between DDL and DML?

• DDL is used for querying data; DML defines database structure.

• DDL defines database structure; DML manipulates data within that structure.

• DDL is a programming language; DML is a markup language.

• DDL and DML are the same and can be used interchangeably.

List three common DML commands.

• WHERE

• INSERT, UPDATE, DELETE

• JOIN

• SELECT

What is a data model?

• A data model is a programming language.

• A data model is a type of software application.

• A data model is a framework that defines how data is structured and related.

• A data model is a method for data encryption.

Name two types of data models.

• Flat file data model

• Hierarchical data model

• Network data model

• Relational data model, Document data model

What is the purpose of normalization in databases?

• To enhance the visual representation of data in reports.

• The purpose of normalization is to minimize data redundancy and enhance data integrity.

• To increase data duplication for faster access.

• To simplify database queries by merging tables.

Explain the first normal form (1NF).

• A table is in First Normal Form (1NF) if it contains nested tables and complex data types.

• A table is in First Normal Form (1NF) if it contains only atomic values, each column has unique names, and each row is unique.

• A table is in First Normal Form (1NF) if it has no restrictions on data types in columns.

• A table is in First Normal Form (1NF) if it allows duplicate rows and columns.

What is a SQL query?

• A SQL query is a programming language for web development.

• A SQL query is a request for data from a database using Structured Query Language.

• A SQL query is a command used to create software applications.

• A SQL query is a type of database management system.