Bz2 SQL Server Reference Documentation

Bz2

Current Version: 11.6.0

Chilkat.Bz2 provides BZip2 compression and decompression for files, memory buffers, and BinData. It can create standard .bz2 file images, decompress .bz2 content back to its original bytes, and support abortable long-running operations.

For an extended overview, see Bz2 Class Overview

Object Creation

DECLARE @hr int
DECLARE @bz2 int
EXEC @hr = sp_OACreate 'Chilkat.Bz2', @bz2 OUT
IF @hr <> 0
BEGIN
    PRINT 'Failed to create ActiveX component'
    RETURN
END

-- ... use @bz2 ...

EXEC @hr = sp_OADestroy @bz2

T-SQL uses the Chilkat ActiveX through the OLE Automation stored procedures. They must be enabled once on the server (EXEC sp_configure 'Ole Automation Procedures', 1; RECONFIGURE;), and the Chilkat ActiveX registered must match the bitness of the SQL Server instance (64-bit for a 64-bit SQL Server). To bind to a specific major version of Chilkat, append the major version number to the ProgID, such as sp_OACreate 'Chilkat.Bz2.11' for Chilkat v11.*.*.

sp_OACreate returns an object token (an int) that is passed as the first argument of every sp_OAMethod, sp_OAGetProperty and sp_OASetProperty call, and released with sp_OADestroy. Objects returned by methods (such as an HttpResponse or JsonObject) are also tokens received through an int OUT parameter; they must likewise be destroyed, and the OUT parameter is NULL when the method fails to return an object. Objects passed as arguments are passed by their token. When an OLE Automation procedure itself fails (non-zero @hr), sp_OAGetErrorInfo describes the error.

Data types: strings are nvarchar(4000); integers, booleans (1 or 0) and object tokens are int; dates are datetime. In the signatures on this page, @success, @iResult, @sResult and the like are the OUT variables receiving a method's return value, @iValue / @sValue receive or supply a property value, and the remaining @ variables are the method's arguments in order.

A string returned through an OUT parameter is limited to 4000 characters. For longer values, retrieve the result as a result set into a table variable instead of an OUT parameter, for example DECLARE @tmp TABLE (outputLine ntext) followed by INSERT INTO @tmp EXEC sp_OAGetProperty @bz2, 'LastErrorText'. See string length limitations for strings returned by sp_OAMethod calls.

Methods that pass or return raw byte arrays are not shown on this page, because varbinary(max) values cannot be exchanged through sp_OAMethod (see varbinary(max) limitation). Use the BinData-based alternatives (methods ending in Bd) or the base64 / hex string-encoded variants instead. Binary properties (such as LastBinaryResult) can be retrieved as a result set into a table variable, as shown in their signatures. Asynchronous (*Async) methods and event callbacks are not available from SQL Server.

Properties

AbortCurrent
EXEC sp_OAGetProperty @bz2, 'AbortCurrent', @iValue OUT
EXEC sp_OASetProperty @bz2, 'AbortCurrent', @iValue
Introduced in version 9.5.0.58

Set this property to 1 to request cancellation of the compression or decompression operation currently executing on this object. Long-running operations check the request periodically; an operation that finishes quickly may complete before the request is observed.

A synchronous call can be cancelled by setting this property from another thread. After cancellation is processed, Chilkat resets the property to 0. If no operation is running, a previously set value is cleared when the next method begins.

Cancellation is cooperative: Setting this property requests an abort; it does not guarantee immediate termination. Check the method's return value and LastErrorText to determine the final outcome.

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DebugLogFilePath
EXEC sp_OAGetProperty @bz2, 'DebugLogFilePath', @sValue OUT
EXEC sp_OASetProperty @bz2, 'DebugLogFilePath', @sValue

If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.

Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.

Possible causes of hangs include:

  • A timeout property set to 0, indicating an infinite timeout.
  • A hang occurring within an event callback in the application code.
  • An internal bug in the Chilkat code causing the hang.

More Information and Examples
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LastBinaryResult
INSERT INTO @tmp EXEC sp_OAGetProperty @bz2, 'LastBinaryResult'

This property is mainly used in SQL Server stored procedures to retrieve binary data from the last method call that returned binary data. It is only accessible if Chilkat.Global.KeepBinaryResult is set to 1. This feature allows for the retrieval of large varbinary results in an SQL Server environment, which has restrictions on returning large data via method calls, though temp tables can handle binary properties.

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LastErrorHtml
EXEC sp_OAGetProperty @bz2, 'LastErrorHtml', @sValue OUT

Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

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LastErrorText
EXEC sp_OAGetProperty @bz2, 'LastErrorText', @sValue OUT

Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

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LastErrorXml
EXEC sp_OAGetProperty @bz2, 'LastErrorXml', @sValue OUT

Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

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LastMethodSuccess
EXEC sp_OAGetProperty @bz2, 'LastMethodSuccess', @iValue OUT
EXEC sp_OASetProperty @bz2, 'LastMethodSuccess', @iValue

Indicates the success or failure of the most recent method call: 1 means success, 0 means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages. Note: This property does not apply to methods that return integer values or to boolean-returning methods where the boolean does not indicate success or failure.

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LastStringResult
EXEC sp_OAGetProperty @bz2, 'LastStringResult', @sValue OUT

In SQL Server stored procedures, this property holds the string return value of the most recent method call that returns a string. It is accessible only when Chilkat.Global.KeepStringResult is set to TRUE. SQL Server has limitations on string lengths returned from methods and properties, but temp tables can be used to access large strings.

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LastStringResultLen
EXEC sp_OAGetProperty @bz2, 'LastStringResultLen', @iValue OUT

The length, in characters, of the string contained in the LastStringResult property.

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VerboseLogging
EXEC sp_OAGetProperty @bz2, 'VerboseLogging', @iValue OUT
EXEC sp_OASetProperty @bz2, 'VerboseLogging', @iValue

If set to 1, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is 0. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

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Version
EXEC sp_OAGetProperty @bz2, 'Version', @sValue OUT

Version of the component/library, such as "10.1.0"

More Information and Examples
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Methods

CompressBd
EXEC sp_OAMethod @bz2, 'CompressBd', @success OUT, @bd
Introduced in version 11.0.0

Compresses the current contents of bd in place. On success, the BinData no longer contains the original bytes; it contains the complete standard BZip2 stream that may be saved with a .bz2 extension.

In-place transformation: Preserve a copy of the original data if it is still needed after this call. A BZip2 stream contains a stream header, one or more compressed blocks with integrity checks, and an end-of-stream marker. It does not contain archive filenames or directory entries.

Returns 1 for success, 0 for failure.

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CompressFile
EXEC sp_OAMethod @bz2, 'CompressFile', @success OUT, @inFilename, @toPath

Reads the file at inFilename and writes its compressed bytes as a standard BZip2 stream to the file at toPath. The output is conventionally given a .bz2 extension.

Both arguments must identify files, not directories. They may be absolute or relative paths, for example data/report.txt and data/report.txt.bz2.

BZip2 is a compressor, not an archive format: A .bz2 file represents one compressed byte stream. It does not store the original filename, directory path, timestamps, permissions, or multiple archive entries. Formats such as .tar.bz2 first combine files in a TAR archive and then compress that TAR stream with BZip2.

Returns 1 for success, 0 for failure.

More Information and Examples
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UncompressBd
EXEC sp_OAMethod @bz2, 'UncompressBd', @success OUT, @bd
Introduced in version 11.0.0

Decompresses the BZip2 stream currently contained in bd in place. On success, the BinData is replaced with the original uncompressed bytes.

Input requirement: bd must contain a complete, valid BZip2 stream, such as the bytes of a .bz2 file or the output of CompressBd. This method operates on binary data and does not perform character-set conversion.

Returns 1 for success, 0 for failure.

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UncompressFile
EXEC sp_OAMethod @bz2, 'UncompressFile', @success OUT, @inFilename, @toPath

Reads the BZip2 stream from the file at inFilename, decompresses it, and writes the original uncompressed bytes to the file at toPath.

Both arguments must identify files, not directories. Chilkat does not derive the destination name from the .bz2 filename because the BZip2 stream does not contain the original filename.

Terminology: This method decompresses BZip2 data; it does not “unzip” a ZIP archive. A .bz2 file normally contains a single compressed byte stream rather than a collection of named files.

Returns 1 for success, 0 for failure.

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