How do you delete a database in MySQL?

Vaibhav Kothia May 31, 2023 0 Comments

To delete a database in MySQL, you can use the DROP DATABASE statement.

For example, to delete a database called “my_db”:

DROP DATABASE my_db;

What is the purpose of the FOR XML clause in SQL Server?

Vaibhav Kothia May 26, 2023 0 Comments

The FOR XML clause in SQL Server is used to return query results in XML format. It is useful for applications that require data in XML format.

For example, the following query returns a list of customer names and their respective orders in XML format:

SELECT c.Name, o.OrderNumber
FROM Customers c
INNER JOIN Orders o
ON c.CustomerID = o.CustomerID
FOR XML AUTO, ELEMENTS;

The output of this query would be something like this:

John Smith
12345

Jane Doe
54321

What is the difference between a clustered and a non-clustered index?

Vaibhav Kothia May 26, 2023 0 Comments

A clustered index is a type of index that physically reorders the data in a table when the index is created. This means that when a clustered index is created, the data in the table is physically sorted in the order of the clustered index key. A non-clustered index does not physically reorder the data in a table when the index is created. Instead, a non-clustered index creates a separate structure that contains the index key and a pointer to the data in the table.

For example, if we have a table called ‘Employees’ with the columns ‘EmployeeID’, ‘FirstName’, and ‘LastName’, we could create a clustered index on the ‘EmployeeID’ column. This would cause the table to be physically sorted by the ‘EmployeeID’ column. We could also create a non-clustered index on the ‘LastName’ column. This would create a separate structure that contains the ‘LastName’ column and a pointer to the data in the table. The data in the table would not be physically sorted by the ‘LastName’ column.

How do you create a table in SQLite?

Vaibhav Kothia May 26, 2023 0 Comments

To create a table in SQLite, you use the CREATE TABLE statement.

For example, to create a table named ‘users’ with three columns: id, username, and email:

CREATE TABLE users (
id INTEGER PRIMARY KEY,
username TEXT NOT NULL,
email TEXT NOT NULL
);

How do you create a database in SQLite?

Vaibhav Kothia May 26, 2023 0 Comments

Creating a database in SQLite is a simple process. All you need to do is open up the command line interface (CLI) and type in the following command:

sqlite3

For example, if you wanted to create a database named “my_database”, you would enter the following command:

sqlite3 my_database

This will create a new database file with the name “my_database.db” in the current directory. You can then use the “.tables” command to see the list of tables in the database.