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Tag archive for: SQL

SQL statement for selecting the latest record in each group

When you have multiple IoT devices of the same type, you may collect data in a single database table.

In such a case, you may choose to group data based on the device ID.

So how do you display the latest data capture from each device?

In this situation, we can choose to run an SQL statement that will return the latest record in each group.

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SQL query to find foreign key constraints that reference columns in a table in oracle database

I was rather new to a system with hundreds of Oracle database tables. There was once when I realized that I had to delete a redundant row from the SYSTEMS_CONFIGURATION table.

As there are foreign key references to the SYSTEMS_CONFIGURATION table, I had to first remove all foreign key references to the redundant SYSTEMS_CONFIGURATION table row prior to deleting it.

This post captures the SQL query which I had ran on my Oracle database to find all the tables which had foreign key references to SYSTEMS_CONFIGURATION table, so that I can write the SQL update statements to delete all child references to the redundant SYSTEMS_CONFIGURATION row prior to deleting it.

My experience with System.Data.SQLite in C#

It was time when simple file IO was not enough to manage data persistence in the .NET application that I had been building. Prior to encountering this situation, I had always wanted to gain practical experience with SQLite. With some googling, I found a .NET wrapper around the SQLite library that I could use in my application. This post documents my experience with using the System.Data.SQLite wrapper.