sql_variant 的大小限制超过

Question

I am trying to save image from fileupload control into the database

public Byte[] bytes;
Stream fs = FileUpload1.PostedFile.InputStream;
BinaryReader br = new BinaryReader(fs);
bytes = br.ReadBytes((Int32)fs.Length);
SqlDataSource2.Update();

protected void SqlDataSource2_Updating(object sender, SqlDataSourceCommandEventArgs e)
{
   e.Command.Parameters["@project_file"].Value = bytes;
}

My database project_file field is set to varbinary(MAX) ,

but it is throwing an error

Parameter '@project_file' exceeds the size limit for the sql_variant datatype.

Please suggest some solution

Answer 1

This is a quote from MSDN on binary and varbinary :

Variable-length binary data. n can be a value from 1 through 8,000. max indicates that the maximum storage size is 2^31-1 bytes. The storage size is the actual length of the data entered + 2 bytes. The data that is entered can be 0 bytes in length. The ANSI SQL synonym for varbinary is binary varying.

varbinary(MAX) can hold an image that is ~2GB of size.

Solution to your problem:

You forgot to specify the type in your code. You need to set the correct SqlDbType .

e.Command.Parameters["@project_file"].SqlDbType = SqlDbType.VarBinary

What you should also do i set the correct Size .

Answer 2

The problem is that sql server assign the type of the parameter as "SQL_Variant".

Try to assing the DbType:

e.Command.Parameters["@project_file"].SqlDbType = SqlDbType.Image
e.Command.Parameters["@project_file"].Value = bytes;

Answer 3

Do not use SQL_VARIANT as your datatype in your C# program. Use the following type instead:

Dim binaryStream As SqlBinary

See http://msdn.microsoft.com/en-us/library/a1904w6t(VS.80).aspx

PS when you use datatypes of Image and Blob you kill a kitten. These datatypes are deprecated and store no more then a varbinary(MAX).

Side note on the use of Image vs Varbinary(max):

image Variable-length binary data from 0 through 2^31-1 (2,147,483,647) bytes.

varbinary [ ( n | max) ] (maximum storage size is 2^31-1 bytes.) Variable-length binary data. n can be a value from 1 through 8,000. max indicates that the maximum storage size is 2^31-1 bytes. The storage size is the actual length of the data entered + 2 bytes. The data that is entered can be 0 bytes in length. The ANSI SQL synonym for varbinary is binary varying.