Quick introduction to SQL, databases and relational theory — Parv The IT Geek

Many people find it daunting when they think about Databases and SQL. I know I found it very scary in the beginning and my early experiences with Database developers left me feeling very small and I thought that maybe I was not good enough to succeed in this field. However, I was luckily given aContinue reading “Quick introduction to SQL, databases and relational theory — Parv The IT Geek”

TSQL Challenge on BeyondRelational.COM — Parv The IT Geek

I was asked by one of my junior colleagues to help him with a puzzle he had seen on BeyondRelational.COM which I thought would be a nice challenge. I liked the premise of the scenario and I always liked a challenge decided to show my colleague how I would approach and resolve this problem. IContinue reading “TSQL Challenge on BeyondRelational.COM — Parv The IT Geek”

SQL JOINS — INNER,OUTER( FULL,LEFT,Right) ,CROSS, SELF — Parv The IT Geek

Have you ever been baffled when people talk about SQL joins? Mystified when you hear inner, outer, cross or self? Ran away in fear at the thought of joining two tables? Well I am about to help you out and face down those fears and explain to you what joins are, the different types andContinue reading “SQL JOINS — INNER,OUTER( FULL,LEFT,Right) ,CROSS, SELF — Parv The IT Geek”

What is Denormalization? — Parv The IT Geek

This is simply the process of combining smaller tables to make larger tables. This can be used to address problems with performance or scalability. This is usually caused by tables being stored in separate files on disks and when databases are being queried there is a requirement for each several files to be accessed accordingContinue reading “What is Denormalization? — Parv The IT Geek”

What is Normalization? — Parv The IT Geek

I would simply describe this as the process of making big tables into smaller tables. The proper definition is that database normalization is a method of reorganising data within tables to reduce the level of dependency. This helps to isolate data so that insertion, deletions and updates in a field can be made into aContinue reading “What is Normalization? — Parv The IT Geek”

What is CRUD (Create, read, update and delete ) — Parv The IT Geek

CRUD is used to describe the majority of commands which are used within databases. Some database professionals I know have used the term BREAD instead which stands for for “Browse, Read, Edit, Add, Delete”. Create Basically this means adding something new This can be used to add new data or objects…. Read This means toContinue reading “What is CRUD (Create, read, update and delete ) — Parv The IT Geek”

What is ACID ( Atomicity, Consistency, Isolation, Durability)? — Parv The IT Geek

Atomicity — this basically means the transaction works or doesn’t and is sometimes called the “all or nothing” rule. I always liken it to an Atomic bomb because they either work or fail. A failed transaction would then enter a state of rollback. Consistency — this means only valid data is written to the database. This means if theContinue reading “What is ACID ( Atomicity, Consistency, Isolation, Durability)? — Parv The IT Geek”

SELECT — The basis of the SQL language — Parv The IT Geek

The SELECT query is the basis of SQL and is the most commonly used syntax within SQL. SELECT basically means retrieve. For example the query SELECT 1 returns 1. SELECT ‘This is an example of the SELECT statement’ As you can see the SELECT query is simply retrieving the number or word and returning thatContinue reading “SELECT — The basis of the SQL language — Parv The IT Geek”