Why Do Square Brackets Appear Around Column Names in MS-SQL Table Designer?

Identifying the Purpose of Square Brackets in MS-SQL Table Designer

Despite attempting to remove the square brackets ([]) from around column names in the MS-SQL table designer, they continue to reappear, indicating a specific purpose.

Explanation of Square Brackets in Identifiers

The square brackets serve to delimit identifiers, which are the names of table columns, variables, and other objects. This delimiter becomes necessary when:

• The column name is a reserved keyword, such as "order" or "from."
• The column name contains special characters, such as spaces or hyphens.

Benefits of Delimited Identifiers

Delimiting identifiers offers several advantages:

• Avoidance of conflicts with reserved keywords: Square brackets prevent conflicts with keywords that have specific meanings in SQL, allowing column names to match these keywords.
• Clarity in naming: Delimiters provide clarity in cases where the column name is not a simple word or may contain special characters.

Example from MSDN

The MSDN documentation provides an example where delimiters are used for clarity and to avoid conflicts with reserved keywords:

SELECT *
FROM [TableX]
WHERE [KeyCol] = 124

In this example, the square brackets around "TableX" are optional, while the brackets around "[KeyCol]" are necessary because "key" is a reserved keyword.

Conclusion

Square brackets in MS-SQL table designer denote that the column names are delimiters to distinguish them as identifiers. This technique ensures compatibility with reserved keywords and enhances clarity in naming conventions.

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