In this article we will analyze what it takes to take an online backup of an Oracle database that is in archived-log mode. In order to take a backup in addition to the datafiles, we should also take a backup of the controlfile,... read more
What are set operators (Union) and how they differ from Joins in SQL
In this article we will analyze the use of set operators, the types that exist and the differences between them and SQL Joins. In the world of SQL (Structured Query Language) many times we will want to combine… read more
How do we find how much more it takes to complete the query and which is delayed (SQL Server Query Profiling)
Many times we will encounter queries that take too long to complete or never complete at all. To find what exactly is at fault the most useful information is the actual execution plan. As the actual execution plan requires the completion of the query, with… read more
How can we see historical image of a table in Oracle Database with Flashback Query
Many times we will need to see what entries the table had some time ago. We may still have to restore it from a wrong update or even drop. In Oracle this is easily done using flashback query… read more
How can we calculate our car insurance premiums in SQL Server using Python (no API)
Let's say we have in SQL Server a table of cars and drivers and we want to find their cheapest premium. This will certainly be possible with an API / Web Service. But this solution would require the… read more
How to force a plan in SQL Server and why not
Sometimes, depending on the value we have given to a parameter, a query may run with a different plan (execution plan) and have a different duration. This phenomenon is called parameter sniffing. This may be due to… read more
How do we return an Oracle database to the previous state of a restore point (Flashback Database to guaranteed restore point)
In the article we will analyze how we can use the flashback database function in a guaranteed restore point in an Oracle database. The flashback database belongs to the category of data protection and provides the possibility to freeze the… read more
What are models in Data Science
What are models in Data Science? In a simple sentence, models are built so that we can make predictions about a trend we are investigating. There are two categories of models: supervised, which we train, and unsupervised, which is done through... read more
Is query join performed between SQL Server and Oracle tables? (aka PolyBase)
In the article we will see a magical way so that we can use in select queries data from external sources (without Linked Server) and more specifically from Oracle Database. What is PolyBase As of SQL Server 2016 the… read more
