Data Analytics and Video Tutorials
A computer that stores data in tables with rows and columns.
DROP and TRUNCATE are two SQL commands that can be used to remove data from a table, but they work in different ways: How to drop a table from a database It is important to remember that if you have the same name spread over a few databases, you should reference the correct databases, to…
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Denormalization is the process of adding redundant data to a database to improve query performance. It involves intentionally violating the normal forms of database design in order to simplify or speed up queries by reducing the number of joins or eliminating the need for certain indexes. The normal forms of database design are a set…
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In SQL, a unique key is a constraint that ensures that the values in a column or set of columns are unique across all rows in a table and that the values cannot be null. A unique key is similar to a primary key, but it differs in that it does not necessarily need to…
In SQL, constraints are rules that are enforced on a table’s data to maintain the integrity and accuracy of the data. Constraints can be applied to one or more columns in a table, and they can be added or removed as needed. Here are some of the most common types of constraints in SQL: Constraints…
In SQL a lot of the times there will be a need to write subqueries that will extract data that you can analyse. But what if you want to use the data as input to another query that can then be used to give you the result you desire? This is is the power of…
Often you will hear about deleting table records with SQL, but how is this achieved, if you have not done it before? In previous videos on SQL we discussed how to update records in SQL , how to insert data into a table in SQL. You could be faced with the scenario where there is…
There are multiple reasons for wanting to update records in a database table, from data quality to enriching your data for any machine learning projects. One example maybe where you want to add a creation date to a record. In this blog post we will look at how to update database records, and also where…
When working with databases in your data analytics projects, most likely you will deal with more than one table. As a result in certain scenarios there will be a link between the tables This will ensure that you can use data from the two or more tables that can be joined together. But how would…
In Data Analytics, that is a very relevant question, and something I look to implement in most projects, sometimes it is too easy to click the shortcut icon to your spreadsheet application! Here we are looking to bring a little automation into these videos. Building on How to import data from files and Removing characters from…