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T-SQL Tuesday

Belated T-SQL Tuesday #165 – Data Jobs Roles

Well I’m a little late to the party this month, I got my weeks mixed and was only reading about this month’s T-SQL Tuesday as the community was posting their responses. So here we go, finally. This month’s ask from Josephine was to consider our understanding or expectations from data job roles. When we see […]

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SQL

Calculating String Lengths

We store a wide variety of data within our platforms, some of which will inevitably be string based. Along with that comes a need to perform manipulation of those strings. When slicing, combining, or manipulating strings one element which we need to consider is the length of the string. Here I wanted to have a […]

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SQL

Recursive Functions and Limitations

When writing functions within SQL Server we sometimes have need to repeat an action multiple times until a given condition is met – also known as Recursion. There are a couple of common ways which this can be implemented which also have their different limitations. A little about recursion Firstly, why do we need recursion? […]

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SQL

Schema Design for Bit Flags

When designing a data schema to store a variety of entities it can be common to require a selection of flags to be stored. There are different ways in which the data can be designed to accommodate this which I wanted to look at here. Examples of these fields could be an ‘Is Active’ flag […]

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SQL

Ranking Function Reference

When processing data there is frequently a need to rank the outputs. This could be to limit a selection of records to return, or provide a type of leader-board for reporting. There are a number of ranking functions within the SQL language which we’ll look at here with examples and outputs. We’ll start with some […]

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SQL

Alternative to Binary Case Statements

When outputting data through a procedure it’s a common use case to add fields which have been calculated from existing data. One way to achieve this is using the CASE statement, however we don’t always need that level of complexity, particularly when we’re looking for a binary result such as ‘Yes’ / ‘No’. An alternative […]

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SQL Server

Object Visibility: Who Can See What

When developing database solutions we’ll typically spend some time considering security requirements, which will result (in part) with database roles being assigned to users or groups of users. Whilst security considerations will likely be focused on what folks can do in our databases, there’s a separate impact on what they can see in them too. I’ve had more than […]

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SQL

Implementing Logging for Rollbacks

Last time out we looked at how data can be persisted even with a ROLLBACK being executed. Here we’re going to take that and look at an example of using it in action. We’ll generate some data – which may be good or bad – and try to add it to a table. If there’s any bad data […]

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SQL Server

Persisting Data Following Rollback

We recently looked at the impact of rolling back transactions on statistics and I thought it would be worth following this up to look at some other objects to see how they behave when a rollback occurs. When rolling back transactions we expect any changes to be rolled back. This isn’t always the case with data, just […]

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SQL

Data Integrity Foundations with Constraints (Part 2)

Last week we started to at the use of constraints to support with data integrity in our databases. As a refresher on our introduction from last time: Data integrity helps give us assurance that our data is accurate, complete, and free from errors or inconsistencies. Some of this comes from making sure that data is correct […]