Insert, update, delete operations in PHP - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the INSERT operation in PHP with databases?

The INSERT operation adds new records (rows) into a database table.

beginner

How do you update a record in a database using PHP?

You use the UPDATE SQL statement with PHP to change existing data in a table, usually specifying which record to update with a WHERE clause.

beginner

What does the DELETE operation do in PHP database handling?

DELETE removes one or more records from a database table based on a condition.

intermediate

Show a simple PHP code snippet to insert a new user with name and email into a MySQL database.

$name = 'Alice'; $email = '[e-mail]'; $sql = "INSERT INTO users (name, email) VALUES ('$name', '$email')"; mysqli_query($conn, $sql);

beginner

Why is it important to use a WHERE clause in UPDATE and DELETE operations?

Without a WHERE clause, UPDATE or DELETE will affect all rows in the table, which can cause data loss or unwanted changes.

Which SQL statement is used to add new data to a table?

A INSERT

B UPDATE

C DELETE

D SELECT

INSERT adds new rows to a table.

What happens if you run an UPDATE statement without a WHERE clause?

A No rows are updated

B Only one row is updated

C All rows in the table are updated

D The table is deleted

Without WHERE, UPDATE affects every row.

Which PHP function is commonly used to execute SQL queries?

A mysqli_query()

B execute_sql()

C run_query()

D sql_execute()

mysqli_query() runs SQL commands in PHP.

What does the DELETE statement do?

A Adds new records

B Changes existing records

C Retrieves records

D Removes records

DELETE removes records from a table.

Which clause specifies which rows to update or delete?

A FROM

B WHERE

C SET

D VALUES

WHERE filters rows for UPDATE or DELETE.

Explain how to safely insert, update, and delete records in a database using PHP.

Think about the SQL commands and how PHP runs them.

Describe the risks of running UPDATE or DELETE operations without a WHERE clause in PHP database code.

What happens if you forget to specify which rows to change?