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 a schema in Oracle Database?

Vaibhav Kothia May 26, 2023 0 Comments

A schema in Oracle Database is a collection of logical structures of data, or schema objects. A schema is owned by a database user and has the same name as that user. For example, a user named “John” would have a schema also named “John”. The schema would contain all of John’s tables, views, sequences, stored procedures, and other database objects.

What are the different types of data types supported by PostgreSQL?

Vaibhav Kothia May 26, 2023 0 Comments

PostgreSQL supports a variety of data types:

1. Numeric Types:
– Integer (e.g. 1,2,3)
– Real (e.g. 3.1415)
– Double Precision (e.g. 2.718281828459045)
– Numeric (e.g. 12345.6789)
– Decimal (e.g. 123.45)

2. Character Types:
– Character (e.g. ‘A’)
– Character Varying (e.g. ‘Hello World’)
– Text (e.g. ‘This is a text’)

3. Date/Time Types:
– Date (e.g. ‘2021-02-19’)
– Time (e.g. ‘15:30:00’)
– Timestamp (e.g. ‘2021-02-19 15:30:00’)
– Interval (e.g. ‘1 day’)

4. Boolean Type:
– Boolean (e.g. true or false)

5. Geometric Types:
– Point (e.g. (1.5, 2.5))
– Line (e.g. [ (1.5, 2.5), (2.5, 3.5) ])
– Box (e.g. ( (1.5, 2.5), (2.5, 3.5) ))
– Circle (e.g. )

6. Network Address Types:
– Inet (e.g. ‘127.0.0.1/32’)
– Cidr (e.g. ‘127.0.0.1/24’)

7. Bit String Types:
– Bit (e.g. B’1010’)
– Bit Varying (e.g. B’1001’)

8. UUID Types:
– UUID (e.g. ‘a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11’)