Joe Celko


Stairway to Database Design

Stairway to Database Design Level 1: Data Elements

Before you start to think about your database schema or tables, you need to consider your data: the type of data it is, the scale you use for values. It needs to be unique, precise and unambiguous. Then you need to name it in such a way that it can be generally understood. Joe Celko explains...

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2019-03-26 (first published: )

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Stairway to Database Design

Stairway to Database Design Level 2: Domains, Constraints and Defaults

A clear understanding of SQL Data Types and domains is a fundamental requirement for the Database Developer, but it is not elementary. If you select the most appropriate data type, it can sidestep a variety of errors. Furthermore, if you then define the data domains as exactly as possible via constraints, you can catch a variety of those problems that would otherwise bedevil the work of the application programmer.

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2019-03-26 (first published: )

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Question of the Day

The Decoded Value

In SQL Server 2025, what is returned from this code:

DECLARE @message VARCHAR(50) = 'Hello SQL Server 2025!';
DECLARE @encoded VARCHAR(MAX);

SET @encoded = BASE64_ENCODE(CAST(@message AS VARBINARY(1000)));
SELECT BASE64_DECODE(@encoded) 

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