SQL Server

Deflate File

Demonstrates how to use the Deflate compression algorithm to compress a file. (The deflate compression algorithm is the most commonly used in the Zip archive file format.)

This code is capable of compressing any size file because the file data is compressed from input to output in a streaming mode. The output file contains only the deflated data (it is not a .zip, and there is no file structure or format).

SQL Server

-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    -- Important: Do not use nvarchar(max).  See the warning about using nvarchar(max).
    DECLARE @sTmp0 nvarchar(4000)
    DECLARE @success int
    SELECT @success = 0

    -- This example requires the Chilkat API to have been previously unlocked.
    -- See Global Unlock Sample for sample code.

    DECLARE @compress int
    EXEC @hr = sp_OACreate 'Chilkat.Compression', @compress OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    EXEC sp_OASetProperty @compress, 'Algorithm', 'deflate'

    -- Deflate this XML file:
    EXEC sp_OAMethod @compress, 'CompressFile', @success OUT, 'hamlet.xml', 'hamletDeflate.dat'
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @compress, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @compress
        RETURN
      END

    -- Inflate back to the original:
    EXEC sp_OAMethod @compress, 'DecompressFile', @success OUT, 'hamletDeflate.dat', 'hamletInflated.xml'
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @compress, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @compress
        RETURN
      END


    PRINT 'Success!'

    EXEC @hr = sp_OADestroy @compress


END
GO