hey what i think is you have variable type of data in your document. you definately need to select proper data type for data. if you have numeric value then select numeric or int whatever suits you. but if you want character data type with support for unicode then you should opt for nvarchar data type.
Also if you are using sql server 2005 and if you can format your document to XML format then you can use XML data type which wud directly save your file into single column.
This is the best option for saving the data.