Functions and aggregate functions in Oracle || query order of execution

Hello, readers! I hope you found my previous posts on Oracle and database useful. I recently learned the grouping functions in Oracle. It’s a very important feature that Oracle offers. Let us see what it is. First of all, we look into the flow through which a query executes in Oracle. For example, we have a query below. Query order of execution flow in Oracle Here, the Clause Trigger flow is as below: Projection [FROM] ——>[WHERE] predicate——-> [SELECT] predicate. So, first of all, Oracle learns FROM where it has to query the data, then it checks the condition as specified […]

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Level pseudo column in Oracle example || Hierarchical query

Hello Readers! I hope my previous articles on Oracle were useful. In this one, I am explaining an Oracle pseudo column. The level is one of the pseudo columns that Oracle adds up with each queried row. It is very useful in some cases, which I am explaining in this article. The level is generated automatically during query processing. By default, each generated row has the same level that is 1. Although levels for each queried row starts varying when we provide some level criteria.This criteria is given using the ‘CONNECT BY’ clause. Level Pseudo column in action. Suppose we […]

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Data views and entity in DBMS

Hello, Readers. In my previous post, I discussed different Database models and types of database. This post aims to explain different views of data and also discusses different types of entities. So, what is an entity in DBMS(Data Base Management System)? An entity is simply a real world object. So, it must have a set of properties that describes it. Logical and physical views of data Data is stored by Oracle in tables. And that data is visible to us in two views, namely Logical View Physical View When you see the data arranged in tables in the form of records, […]

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Database models and types of database

Hello, reader. A database has many models depending on whom the database is targeted for use. Different people having different requirements would want to use the database. So, they get different database models to use. Common Database Models Mainly, the following database models are used:- Strategic database model Tactical database model Clerical database model The strategic database model is for those group of users that need to work on building strategies based on the data they have in the database. And they generally don’t perform day to day transactions on the data. The Tactical database model refers to utilizing specific […]

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Oracle database tutorials for beginners

Hello, readers! This is going to be a short blog which is targeted at Learning Oracle database concepts and provide simple Oracle database tutorial. The difficulty level of understanding this Oracle database tutorial blog stuff is ‘beginner’, so experts stay away. I am myself exploring Oracle right now, so please excuse any mistakes. All comments, suggestions are most welcome. Make sure you add this website to your browser bookmark if you are willing to learn upcoming Oracle database tutorials. Learn more about the Oracle database versions and features here : link to Oracle. You can request for tutorials and concepts […]

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