Understanding SQL Concepts and Database

During a computer science class, Scarlett asked her classmates, "What does SQL stand for?"

• Structured Query List

• Simple Query Language

• Structured Query Language

• Structured Query Logic

Answer explanation

SQL stands for Structured Query Language, which is the standard language used for managing and manipulating databases. The other options do not accurately represent the full name of SQL.

In a database project for their class, Aria and Daniel are discussing the purpose of Data Definition Language (DDL) in SQL. What do they conclude?

• To perform calculations on data.

• The purpose of DDL in SQL is to define and manage the structure of database objects.

• To manage user permissions in the database.

• To retrieve data from the database.

Answer explanation

The correct choice highlights that DDL (Data Definition Language) in SQL is specifically used to define and manage the structure of database objects, such as tables and schemas, which is essential for database design.

Emma is trying to organize her school database. Which SQL statement should she use to create a new table for student records?

• ADD TABLE

• CREATE TABLE

• INSERT INTO

• MODIFY TABLE

Answer explanation

The correct SQL statement to create a new table is 'CREATE TABLE'. The other options, such as 'ADD TABLE' and 'MODIFY TABLE', are not valid SQL commands for this purpose.

In a database management class, William is learning about SQL commands. He comes across the ALTER TABLE statement and wonders what its function is.

• To create a new table in a database.

• To retrieve data from a table in a database.

• To modify the structure of an existing table in a database.

• To delete an existing table from a database.

Answer explanation

The ALTER TABLE statement is used to modify the structure of an existing table in a database, such as adding or deleting columns, or changing data types. This distinguishes it from creating, retrieving, or deleting tables.

In a school database, define a primary key for student records.

• A primary key is a type of foreign key in a database.

• A primary key is a unique identifier for a record in a database table.

• A primary key can contain duplicate values in a table.

• A primary key is used to store large amounts of data in a database.

Answer explanation

A primary key uniquely identifies each record in a database table, ensuring that no two records can have the same key value. This is essential for maintaining data integrity and enabling efficient data retrieval.

In a school database, what is a foreign key?

• A foreign key is a field in a table that links to the primary key of another table.

• A foreign key is a unique identifier for a table.

• A foreign key is a type of primary key.

• A foreign key is a field that cannot be null.

Answer explanation

A foreign key establishes a relationship between two tables by linking a field in one table to the primary key of another. This is crucial for maintaining referential integrity in a database.

In a school database, how does a foreign key enforce referential integrity when linking students to their classes?

• A foreign key can reference multiple primary keys at once.

• A foreign key allows any value in the foreign key column without restrictions.

• A foreign key enforces referential integrity by ensuring that every value in the foreign key column corresponds to a valid value in the referenced primary key column.

• A foreign key is used to delete records from the database without any checks.

Answer explanation

A foreign key enforces referential integrity by ensuring that every value in the foreign key column corresponds to a valid value in the referenced primary key column, preventing orphaned records.

Abigail is working on her database and needs to remove a table that is no longer needed. What SQL statement should she use to delete the table?

• DROP TABLE table_name;

• REMOVE TABLE table_name;

• DELETE TABLE table_name;

• CLEAR TABLE table_name;

Answer explanation

The correct SQL statement to delete a table is 'DROP TABLE table_name;'. This command permanently removes the table and its data from the database, while the other options are not valid SQL syntax.

Ethan is working on a database project for his class. What is the purpose of the DROP statement in SQL?

• To retrieve data from a database.

• To remove a database object permanently.

• To modify an existing database object.

• To create a new database object.

Answer explanation

The DROP statement in SQL is used to remove a database object, such as a table or view, permanently. This means that all data and structure associated with the object will be lost, making the correct choice "To remove a database object permanently."

In a database project for her class, Emma needs to understand the term 'database constraints'.

• Database constraints are only applicable to large databases.

• Database constraints are optional rules that can be ignored.

• Database constraints are methods for data visualization.

• Database constraints are rules that enforce data integrity and validity in a database.

Answer explanation

Database constraints are essential rules that ensure data integrity and validity within a database. They help maintain accurate and reliable data, making the correct choice: 'Database constraints are rules that enforce data integrity and validity in a database.'