Member Avatar for jozcar@yahoo.co

command.Parameters.Add("@BrandName", SqlDbType.VarChar);
command.Parameters.Add("@BrandName", SqlDbType.VarChar,50);


The above are two possible ways to add a parameter on SqlCommand, is there any benefit on specifying the value 50.

  • 2 Contributors
  • 2 Replies
  • 97 Views
  • 15 Hours Discussion Span
  • Latest Post Latest Post by jozcar@yahoo.co

Dani AI

Generated

Short answer: specifying a length is optional for many input parameters but important in some cases. The Size/length you give a SqlParameter controls how much data the provider will accept or allocate for that parameter — it can cause client-side truncation and is required to size output buffers correctly. See the Microsoft docs for the SqlParameter.Size property for the exact behavior and rules: SqlParameter.Size.

Key practical points:

  • Output parameters: always set the size to at least the expected length. If you do not, the value returned from SQL Server can be truncated because the client buffer is not sized correctly.
  • Input parameters: leaving size unset usually works because ADO.NET will use the actual value length when transmitting. However, if you explicitly set a smaller size than the value, the provider will truncate the value before sending — so do not rely on automatic truncation for correctness.
  • Type/size mismatches can lead to implicit conversions on the server and poor plans. Explicitly declaring the correct SqlDbType and an appropriate size (matching the column or SP parameter) helps avoid those issues. Avoid relying on AddWithValue because it can infer wrong types/sizes; Microsoft has guidance on that here: .

Recommended rules of thumb:

  • For returned/output data, always set Size.
  • For input data, set Size when you want to be explicit or to match the database definition; otherwise it is safe to omit.
  • Validate lengths in your application rather than depending on silent truncation.

As suggested, trimming/truncation can occur — but it is deterministic and documented; use Size deliberately when you need that behavior and avoid relying on it accidentally.

Recommended Answers

All 2 Replies

Member Avatar for Ramy Mahrous

I don't know but it may trim the string before executing DML statement, it sure better than doing such via SQL engine. Jusing guessing good question (Y)
And it may have no effect

Member Avatar for jozcar@yahoo.co

well, this has being bugging me for a while, tanks for the reply

Be a part of the DaniWeb community

We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.