MongoDB updateOne changes one document, and its result object shows how many documents matched and how many changed. This post tests $set, $inc, updateMany, upserts and the replaceOne mistake that wipes every other field.
MongoDB find: Filters, Projections and Sorting for SQL People
MongoDB find returns the documents that match a filter. This post tests find, findOne, $gt, $in, $and, $or, projection, sort, limit and countDocuments on 18 grocery products, each next to its SQL equivalent.
MongoDB insertOne and insertMany: Adding Documents the Right Way
MongoDB insertOne adds a document and insertMany adds a list. This post tests both with a unique index, a generated _id and a duplicate key in the middle of a batch, comparing ordered: true with ordered: false and showing what landed.
Getting Started With mongosh: Databases, Collections and Documents
mongosh is the shell that connects you to MongoDB. This post connects, creates a database and a collection on the first write, and stores a document. It explains the _id, the BSON types and the habits that surprise SQL Server people.
HAS_DBACCESS Function: List the Databases You Can Open
The HAS_DBACCESS function tells you whether the current login can open a database. One query over sys.databases turns it into a list, and this post tests six databases to show what each zero means: no user, offline, restricted or a busy single user slot.
Why FLOAT Math Does Not Add Up in T-SQL Queries
See why FLOAT math produces approximate sums and comparisons in SQL Server, then use DECIMAL or tolerance checks for the right data.
Windows Path Variable: Run oStress From Any Folder
The Windows Path variable is a list of folders that Windows searches when you type a program name. This post shows how to test a change in one window, add a folder for good and check that it works. It uses oStress and sqlcmd as the examples and ends with rules for a clean Path.