SQL DBA Blog: Home
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The Evolution of SQL Server: Every Version from 1989 to 2025
🕐 Version history, with the support dates that actually matter Every release from the 1989 OS/2 original to SQL Server 2025, what each one changed for the people running it, and which ones are still receiving security updates today. Lifecycle dates checked against the builds and lifecycle reference, which is regenerated after each patch release.…
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Cannot Execute As the Database Principal (Error 15517)
SQL Server error 15517, cannot execute as the database principal. Why dbo maps to an orphaned owner after a restore and the one-line fix.
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Silent Failures: The SQL Server Problems That Never Raise an Error
Twelve SQL Server failures that produce no error, no failed job and no alert, why each stays silent, and one script that finds them all.
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SQL Server Login Migration: What Gets Silently Left Behind
sp_help_revlogin carries more than you think, including disabled state. What nothing carries, and why the script you actually ran matters more.
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CREATE USER WITHOUT LOGIN vs Contained Database Users
Both look like a user with no login and they are opposites. How to tell them apart, what each is for, and the migration break that fails silently.
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The sqldba MCP Server: Give Your AI Assistant a Verified SQL Server Reference
The reference behind this site, as six tools an AI assistant can call: error numbers, wait types, patch levels and scripts, hand-verified rather than scraped. It never connects to your SQL Server, and it refuses rather than guessing.
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Cannot Resolve the Collation Conflict (Error 468)
Nothing is broken when you see 468. Two sides of a comparison store text under different rules, and SQL Server will not guess which should win. The fix is one line, and it does not belong on the column.
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Logical Consistency-Based I/O Error in SQL Server (Errors 823 and 824)
823 means the storage failed the read and said so. 824 means it succeeded and the data was wrong. Which one you have changes who you escalate to, and what you protect first.
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Cannot Recover the Master Database (Error 3417) and What the Log Actually Says
3417 is the summary, not the diagnosis. Four kinds of master damage reproduced in a throwaway container, and 3417 appeared in none of them. Here is what each one actually logs.
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The Database Principal Owns a Schema in the Database and Cannot Be Dropped (Error 15138)
🚨Part of the SQL Server Errors series, the exact messages and what actually causes them.Related pillar: Security What Msg 15138 Says Msg 15138 · Level 16 · State 1 The database principal owns a schema in the database, and cannot be dropped. ⚡Reassign, then drop. ALTER AUTHORIZATION ON SCHEMA::[name] TO [dbo] clears it, but check…
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- SQL Server Configuration Manager: Where to Find It and What a DBA Uses It For
- DBA Scripts: Get Failed Login Summary
- Query Was Fast Yesterday, Slow Today: Find What Changed
- The Current Transaction Cannot Be Committed (Error 3930)
- Sort and Hash Spills to TempDB: Find the Query and Fix the Grant
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