This article explores the 'shadow copy' and 'disk virtualization' services built into the Windows operating system and explains a basic solution demonstrating how the technology is used to copy the data and log files for a live SQL Server database into an 'image', from which we can create multiple, lightweight copies, or clones, of the original database.
2025-10-22 (first published: 2021-04-29)
6,360 reads
Learn how indexes can help you with more than just querying data.
2025-10-22
18,317 reads
I’ve seen the SQL EXISTS keyword in Microsoft SQL Server T-SQL code and don’t understand it well. What does it do? How do I use it? Are there best practices around SQL IF EXISTS?
2025-10-22
Learn how ledger databases and ledger tables work in SQL Server 2022.
2025-10-20
18,670 reads
VIEWs are an undervalued and underused feature in SQL. They basically consist of a query that has been given a name, and a parameter list, so can be used like an inline macro. Technically, you’re supposed to think of it as a virtual table.
2025-10-20
This article shows how to use Python to create a REST API for your application that developers can use to access the database.
2025-10-17
7,746 reads
Most SQL bulk insert and SQL Server openrowset tutorials skip file access issues that can stop imports cold. Both the bulk insert statement and openrowset function rely on the SQL Server service account to read a source file. The SQL Server service account must have read permission on the file or its folder. It is also convenient to have read & execute as well as list folder content permissions.
2025-10-17
I have never seen a T-SQL feature that people love as much as NOLOCK.
2025-10-15
Learn how to migrate SSRS reports to a new server using SSRS Reports Migration Wizard. Step-by-step guide to move reports, data sources, and datasets in just a few clicks.
2025-10-13
6,341 reads
You have a Power BI project that generates real-time reports for an inventory management system that uses SQL Server. You are aware that Power BI performance is heavily influenced by how your data is structured in SQL Server but don’t have a clear understanding of how to optimize your SQL data structure for Power BI. In this article, we look at different ways to structure the data and tables to help improve Power BI query performance.
2025-10-13
When I put together the invitation for T-SQL Tuesday #202, I wasn't sure what...
By Steve Jones
My life has some crazy travel stretches for sure. Between speaking, office visits, customer...
In Part 1, we saw how ‘Vamana’ represents vectors as nodes, connects them with...
Comments posted to this topic are about the item Server-Level Table sizes
Comments posted to this topic are about the item Optional Parameter Plan Optimization in...
There is a table tmp_tab:
CREATE TABLE tmp_tab ( id int, val int );
INSERT INTO tmp_tab VALUES (1, 1), (2, NULL), (3, 3), (4, 4), (5, 5);You want to order the rows ids by the following expression:
ISNULL(val, id) + 1Which of the following queries produces the expected ordering and why? (Select all correct) See possible answers