You can probably make use of binary data type in your database. Store your file data and file name separately in two columns. Have file data as bytes. C# has a way to get bytes from a file:
File.ReadAllBytes[
^]
Get the byte array and write it to the file data column. Store the file name in another column.
When you read it back, simply use the following method after getting the bytes into a byte array:
File.WriteAllBytes[
^]