In PostgreSQL, we can use the || operator to concatenate two arrays. We can also use it to append or prepend a (compatible) non-array value to an array.
DBMS
Database Management Systems
Fix Error “Truncate failed on table … because it is not a supported operation on system-versioned tables.” in SQL Server
If you’re getting an error that reads something like “Truncate failed on table ‘test.dbo.ProductInventory’ because it is not a supported operation on system-versioned tables.” in SQL Server, it’s probably because you’re trying to truncate a system-versioned temporal table.
In SQL Server, if a table is defined as a temporal table, we can’t truncate it while it’s using system-versioning.
Understanding Domains in PostgreSQL
PostgreSQL offers a handy feature called domains that can greatly enhance data integrity and simplify database design. In this article, we’ll explore what domains are, how they work, and when to use them in our database projects.
How to Update an Array in PostgreSQL
PostgreSQL allows us to create arrays and store them in the database as an array type. We can then go back later and update those arrays as required.
We can either replace the whole array, append or prepend elements, or update individual elements within the array. When we update individual elements, we can update one element or a whole slice. Below are examples of updating an array in PostgreSQL.
A Quick Look at the MD5() Function in PostgreSQL
In PostgreSQL, the md5() function computes the MD5 hash of the specific text, and outputs the result in hexadecimal.
We pass the text as an argument when calling the function.
How to DROP Tables with Foreign Key Relationships in PostgreSQL
Nothing pulls me out of the “zone” quicker than attempting to drop a table, only to be told “Nope, that table has a dependency!”.
Granted, this usually only happens in my development environments, as I rarely have any need to drop tables in a production environment.
And that’s probably why it “pulls me out of the zone”. I suddenly have to stop and start thinking about what tables contain foreign keys to the one I’m trying to drop. In dev environments, we’re often trying things out and so it’s not out of the question that we might inadvertently try to drop a table without realising it has dependent objects.
Fortunately, when we’re working with PostgreSQL, we have a quick and easy method to overcome this barrier.
2 Functions that Return the Position of a Substring within a String in PostgreSQL
PostgreSQL sometimes provides us with multiple functions that basically do the same thing. Such is the case with the following two functions that return the position of a given substring within a string.
A Quick Look at TO_HEX() in PostgreSQL
In PostgreSQL, we can use the to_hex() function to convert a number to its equivalent hexadecimal representation.
The function accepts the number as an integer or bigint, and it returns the result as a text representation of its hexadecimal equivalent.
How to TRUNCATE a Temporal Table in SQL Server
Temporal tables in SQL Server provide a powerful way to track historical data changes. However, when it comes to clearing out data from these tables, the standard TRUNCATE statement doesn’t work the same as it does on normal (non-temporal) tables.
This article will guide you through the process of truncating a temporal table while maintaining its integrity.