MySQL mcq questions and answers | MySQL MCQs

This question is about the UPDATE statement in MySQL. The UPDATE statement is used to change data in existing rows of a table.

We need to find the keyword that is used to actually assign the new values to the columns we want to change.

Let's look at the options:
* Option A: ASSIGN - This keyword isn't used in the UPDATE statement.
* Option B: SET - This is the keyword used in the UPDATE statement to assign values to columns.
* Option C: MARK - This keyword isn't used in the UPDATE statement.
* Option D: GET - This keyword isn't used in the UPDATE statement.

So the correct answer is Option B: SET .

Here's a simple example of how you'd use the SET keyword in an UPDATE statement:

```sql UPDATE Customers SET FirstName = 'John', LastName = 'Doe' WHERE CustomerID = 1; ```
This statement updates the Customers table. It sets the FirstName to 'John' and LastName to 'Doe' for the row where CustomerID is 1.

This question is asking about which programming language, Perl or PHP, uses less memory when running a program.

Think of it like this: when you run a program, it takes up some space in your computer's memory. The smaller the memory footprint, the less space the program takes up.

Here's a breakdown of the options:

* Option A: Perl
* Option B: PHP
* Option C: Same
* Option D: Machine dependent

The correct answer is Option B: PHP. PHP generally has a smaller memory footprint than Perl. This means PHP programs tend to use less memory, especially when handling large amounts of data.

While Option D: Machine dependent could be a factor, PHP is generally recognized for its efficiency in memory usage compared to Perl.

This question asks about how to create a new database in MySQL.
Think of it like building a new storage container for your data.
We need a special command to tell MySQL to make this new container.
Out of the options, only one is used to create things:
CREATE is the keyword used for making new things in MySQL.
So the answer is Option A: CREATE.
The other options are not used for creating databases.
SET is for changing settings, SETUP isn't a MySQL keyword, and LINK is for connecting to existing databases.

This question is about the safety of relocating a database in MySQL.

Imagine your database is like a big library full of important information.

If you want to move this library to a new location, you need to make sure no one is using the books while you're moving them, right?

The same applies to your database. If the server is running, it means people are using the database (like borrowing books from the library).

To avoid data loss or corruption during the move, you need to stop the server (close the library) before you start relocating the database.

Therefore, the answer is Option A: True.

This SQL statement is used to delete rows from a table. Let's break it down:

DELETE FROM xyz : This part tells the database to delete rows from the table named xyz.
WHERE abc = 5 : This part specifies which rows to delete. It means "delete the rows where the column named abc has a value of 5".

So, abc in this statement represents the column name in the table xyz.

Therefore, the correct answer is Option A: column name.

This question asks about a specific mode in MySQL that changes how the database interprets double quotes (").

In MySQL, double quotes can be used for a few different things. They can be used to surround identifiers, like table or column names. They can also be used to enclose string literals, which are just plain text values.

The mode that determines how MySQL handles double quotes is called ANSI_QUOTES. When this mode is enabled, MySQL follows the ANSI SQL standard, and double quotes are specifically recognized as identifier quoting characters. This means that when you use double quotes around a name, MySQL will treat it as a name, even if it contains reserved keywords.

Let's break down the options:

Option A: ANSI_DQ is not a valid mode in MySQL.
Option B: ANSI_QUOTES is the correct answer. This mode tells MySQL to interpret double quotes as identifier quoting characters, adhering to the ANSI SQL standard.
Option C: ANSI_RECG_QUOTES and Option D: ANSI_RECG_DQUOTES are not valid modes in MySQL.

So, the answer is Option B: ANSI_QUOTES.

This question is about understanding the parts of a MySQL trigger creation statement.

The code snippet is:
CREATE TRIGGER abc (...) (...) ON def FOR EACH ROW ghi;

Let's break it down:

* CREATE TRIGGER: This tells MySQL you're creating a trigger.
* abc: This is the name you're giving to the trigger.
* (...) (...) ON def: These parts define what happens when the trigger is activated, and on which table (def) it operates.
* FOR EACH ROW: This means the trigger will run for each row affected by an event on the table.
* ghi: This is the code that will be executed when the trigger is activated.

Therefore, the answer is Option A: trigger name.

abc is the name of the trigger you're creating.

This question asks about how MySQL's C client library works with different compiler settings.

Let's break it down:
* MySQL C Client Library: This is a set of code that allows you to interact with MySQL databases using the C programming language.
* Static Linking: This means that the client library is directly included within your application. It's like having all the ingredients for a cake baked right into the cake. * Compiler Options: These are settings you tell your compiler (the program that turns your code into executable files) to use. Think of these as "instructions" for how to build your application.

The Question:
Can the client library and the application it's linked to have different compiler options?
The Answer:
The answer is Option A: True.
This is because the client library (the pre-compiled code) is a separate entity from your application. When you link it statically, it's combined with your application's code at compile time. However, the compiler options used for the client library during its initial compilation don't necessarily have to match the options you use to compile your application.

Think of it like this: The client library is like a pre-made ingredient (like pre-made cake mix). You might want to use a different oven temperature (compiler option) when baking the cake with the mix than the temperature used when it was made. It's still possible!

This question asks about how we specify a column when deleting data from a single table in MySQL.
Let's break down the options:
Option A: qualification not necessary
This is incorrect. When deleting data, you usually need to specify which column you are working with.

Option B: column name
This is the correct answer. You typically use the column name directly in your DELETE statement to indicate which column's data you want to delete.

Option C: table name
While you need to specify the table name in your DELETE statement, it's not used to qualify a column name. The table name is used to indicate which table you're working with.

Option D: database name
The database name is rarely needed when deleting data from a specific table. You usually work within the context of a specific database.

Therefore, the answer is Option B: column name.

This question is asking about triggers in MySQL. Triggers are like special instructions that automatically run when certain things happen in your database.

They are usually used for things like:
     - Keeping data consistent (making sure changes in one part of the database are reflected in other parts)
     - Auditing changes (recording who changed what and when)
     - Enforcing business rules (making sure data follows certain rules)

Now, the question asks which of the following don't support triggers. Here are the options:
     A: delete - Triggers can definitely be used when you delete data.
     B: update - Triggers can also work when data is updated.
     C: insert - You can also use triggers when new data is inserted.
     D: views - This is the answer! Views are virtual tables that don't actually store data. You can't create triggers on views.

So the correct answer is Option D: views.