Introduction This article celebrates a classic algorithm [1] of Dijkstra (1930 – 2002) which finds a path of minimal cost between any pair of nodes in an undirected graph. His procedure is widely recognized as a fundamental tool for examining communication and transportation networks (eg. Google Maps) and is surprisingly simple. By his own admission, […]
2024-01-05
8,560 reads
Introduction The sp_HorizontalTree procedure introduced here may be used to audit tables with dependent columns. A column is dependent on another if the meaning of the first column depends on the meaning of the second. For example, in a table containing accounting information, the meaning of a Fiscal Quarter column depends on the Fiscal Year to […]
2023-06-16
2,417 reads
Introduction This article shows how to script a basic merge between two tables, without using MERGE. This can be handy when you're merging a pair of tables with hundreds of columns, since the script doesn't know anything about them. This technique introduces and populates some auditing columns (IS_DELETED, IS_INSERTED, IS_UPDATED, TRANSACTION_DATE) for each record, and runs fast. […]
2023-02-20 (first published: 2020-04-14)
18,756 reads
In this article, Glen Cooper provides code that allows you to process a tree, or undirected graph of data. Lots of hierarchies fall into this category and the ability to process them is valuable in many reporting situations.
2023-01-20
3,348 reads
Learn a little basic graph theory in this article that replaces a GROUP BY clause.
2022-07-04 (first published: 2019-10-17)
11,984 reads
This article presents a way that finds a perfect match in any bipartite graph or shows why one cannot exist.
2021-09-06
2,939 reads
Introduction This article shows how common table expressions (CTE) in SQL Server are naturally suited for navigating trees, such as finding its longest path, or diameter. Recall that a tree is an undirected graph where unique paths exist between any two nodes (i.e. vertices). Any node may be selected as its top node, with its […]
2021-04-19
8,121 reads
This article shows how to solve a gaps and islands problem using simple algebra.
2020-03-10
5,009 reads
In this article, we see how SQL can be used to determine matches between two groups, given a set of preferences.
2020-01-23
7,179 reads
An interesting tutorial for linking SQL Server to a Blackberry device and viewing images.
2011-02-09
11,424 reads
By Vinay Thakur
I wrote about TempDB Internals and understand that Tempdb plays very important role on...
By Vinay Thakur
continuing from Day 1 where we covered the history of AI and GPT family,...
Comments posted to this topic are about the item A Quick Restore
Comments posted to this topic are about the item Guarding Against SQL Injection at...
I have a quick question on Ola Hallengren Index Optimize Maintenance . Do we...
While doing some testing of an application, I wanted to reset my environment after doing some testing with this code:
USE DNRTest BACKUP DATABASE DNRTest TO DISK = 'dnrtest.bak' GO /* Bunch of stuff tested here */RESTORE DATABASE DNRTest FROM DISK = 'dnrtest.bak' WITH REPLACEWhat happens if this runs, assuming the "bunch of stuff" isn't anything affecting the instance. See possible answers