Tag Archives: Access OLE Export

Using the column name in your file naming convention in Access OLE Export / SQL Blob Export

When you export images and files using Access OLE Export / SQL Blob Export and each row of your table or result set contains multiple columns that contain the blob data e.g.

you could previously only use the column index in the file naming convention to identify the source column of the exported file e.g.

which would then name the exported files this way:

Files with the suffix 0002 indicates that it was exported from the 2nd column (ThumbnailPhoto), and 0003 from the 3rd column (LargePhoto).

From version 3.17 onwards, you can now use the column name in the naming convention, using the <%columnname%> tag e.g.

The exported files are then named this way:

which is more meaningful.

 

Merge or combine TIFF files

We had a user who recently asked if SQL Blob Export is able to merge or combine the extracted single-page TIFF files from her database into multi-page TIFF files.  This feature isn’t built-in, but we have provided an external command line application (MergeTiff) that you can freely use to perform the same task.

You can use MergeTiff on any tif files, including those extracted using SQL Image Viewer, SQL Blob Export, and Access OLE Export.  It is important that the extracted files use names that group the pages into the right order.

For e.g. the default naming convention for exported files in SQL Image Viewer is row and column index, so assuming each row in your result set only had 1 blob column, your exported files would be named this way:

0001_0001.tif
0002_0001.tif
0003_0001.tif

This isn’t going to help MergeTiff determine how to group the files.  What you need is a ‘grouping’ value e.g. say a CustomerID column that identifies the customer each image belongs to.  We then use this naming convention in SQL Image Viewer/ SQL Blob Export/ Access OLE Export:

<CustomerID>_<%row:0000%>

and our exported files may be named this way:

A00123_0001.tif
A00123_0002.tif
A00123_0003.tif
C72186_0006.tif
D12472_0007.tif
E88822_0004.tif
E88822_0005.tif

In this way, we know that for customer A00123, we need to merge 3 files, for customer E88822, we need to merge 2 files, and so on.

To use MergeTiff, you need to provide at least 1 parameter:

  • the search pattern for the files to process using the -i  parameter e.g.

MergeTiff.exe -i “g:\exported images\*.tif” 

Other parameters supported by MergeTiff:

-o

this is the output folder to store the merged files.  If not provided, the merged files will be stored in the same folder as the source files.  If you want to store the merged files in a different folder, you would need to provide the -o parameter e.g.

MergeTiff.exe -i “g:\exported images\*.tif” -o “g:\exported images\merged\”

-d

this is the delimiter that the source file name uses to separate elements, default value is _

In our example, our file name elements use the underscore character e.g. _.  You might use another symbol e.g.

A00123-0001.tif
A00123-0002.tif
A00123-0003.tif
E88822-0004.tif

In this case, you need to provide the -d parameter and the delimiter character e.g.

MergeTiff.exe -i “g:\exported images\*.tif” -o “g:\exported images\merged\” -d “-“

-g

this is the grouping element index, default value is 1.  In our example, the grouping element is the first element i.e. all the characters before the first delimiter i.e.

A00123
E88822
C72186
D12472
E88822

If instead our file named had been named this way:

scanneddocsA00123_invoice1005_A00123_0001.tif
scanneddocsA00123_invoice1005_A00123_0002.tif
scanneddocsA00123_invoice1006_A00123_0003.tif
scanneddocsC72186_invoice1008_C72186_0006.tif
scanneddocsD12472_invoice2010_D12472_0007.tif

and we still wanted to merge all documents belonging to the same customer, then our grouping element is the 3rd element, and we would need to use the -g parameter e.g.

MergeTiff.exe -i “g:\exported images\*.tif” -o “g:\exported images\merged\” -g 3

-n

this is the naming element index, default value is 1.  Following on from the above example, supposing we merge our files by invoice number instead of customer code, we would need to use both the -g and -n parameters e.g.

MergeTiff.exe -i “g:\exported images\*.tif” -o “g:\exported images\merged\” -g 2 -n 2

-ow

use this parameter to overwrite any existing files of the same name

If you want MergeTiff to overwrite any existing files, use the -ow parameter e.g.

MergeTiff.exe -i “g:\exported images\*.tif” -ow

-r

use this parameter to also process files in the input path subfolders

To process files recursively beneath the input path, use the -r parameter e.g.

MergeTiff.exe -i “g:\exported images\*.tif” -r

You can download MergeTiff from here.

Incorrectly extracted files in Access OLE Export/SQL Blob Export

Access OLE Export / SQL Blob Export may sometimes extract items that appear to be wrong.  For e.g. it might extract an expected PDF file as an image file.  To troubleshoot such issues, we need your help in sending us the data exactly as stored in your database to us for further investigation.

One way to extract the data is to use SQL Image Viewer.  Once installed, connect to the same database you were trying to extract your items from, and run your query to select the wrongly extracted item(s).

Select the item you’re having problems with, right click to bring up the context menu, and select the View as hex option.

SQL Image Viewer will display the selected item in a hex viewer.  Click on the Save button to save the raw data to a file.

and send us that file at support@yohz.com.  Having the raw data to work with will help us immensely to determine why Access OLE Export / SQL Blob Export appears to be extracting your files wrongly.

 

Naming the exported files in Access OLE Export and SQL Blob Export

When exporting your database blobs to files using Access OLE Export and SQL Blob Export, the default naming convention is the row number and column number (of the blob column).

For example, if your data set contains 10 rows and 2 columns of blobs (say columns 2 and 5), the files will be named in this way:

0001_0002.<file extension>
0001_0005.<file extension>
0002_0002.<file extension>
0002_0005.<file extension>

0010_0002.<file extension>
0010_0005.<file extension>

You can change the naming convention to use values from the exported table or data set (if running a SQL query).  For example, if your table or data set has the following columns:

and you want to name the exported files from the SalesOrderImage column using the SalesOrderID value, you would use the following naming convention:

The exported files will then be named this way:

  • 43659.<file extension>
  • 43660.<file extension>
  • 43661.<file extension>

and so on.

Simply enclose any column values you want to use in angled brackets, as in <SalesOrderID> above.  You can combine multiple columns together, so for e.g. using  <Category>_<SalesOrderID> will name the files

  • Bikes_43659.<file extension>
  • Bikes_43660.<file extension>
  • Components_43661.<file extension>

and so on.

There are also attributes tags you can use as part of the naming convention.  We have already described the <%column%> and <%row%> tags above.  There is also a <%size%> tag, which would return the file size value.  You can freely mix column tags and attribute tags in the naming convention.

Using tags in output folders

You can also use column tags as part of the folder naming convention, if you need to store the files in individual folders or grouped by folders.  For e.g. in this sample data set:

if we wanted to group our exported images by the Category value, we would enter F:\exports\<Category>\ as our output folder naming convention

This will result in the first 2 files stored in the F:\exports\Bikes\ folder, the 3rd file in the F:\exports\Components\ folder, and so on.  You can use multiple column tags in the folder naming convention if required.  Access OLE Export and SQL Blob Export will create the folders if they do not already exist, as long as you have the permissions to create those folders.

OLE-Object types

For files extracted from OLE-Object packages, you have the option of using the original file name:

or a custom name using column and attribute tags, as described above.  If using a custom name, you can use the <%package_file_name%> tag, allowing you to mix column values with the original package file name e.g.

 

Connecting to a Microsoft Access (.accdb) database

If you have problems connecting to a Microsoft Access database with the .accdb extension (using SQL Image Viewer, SQL Blob Export or Access OLE Export) and see this error:

there are a few possibilities this error is being raised.

You can connect to that database using Access on the same machine

If you have Access installed on the machine and can connect to the .accdb file without problems, then it’s possible that you are using Microsoft Office 365.

Microsoft Office 365 runs in a self-contained virtual environment, and 3rd party products do not have access to the necessary library files to connect to the .accdb file.  In this situation, you will need to install the Microsoft Access runtime files.  You have the following options:

There is, however, one caveat. You cannot install Office 365 and the above Redistributable/Runtime files of the same major version together. You will have to install the Redistributable/Runtime files of a lower version than your current Office 365 version. For example, if you have Office 365 in version 2016 installed, you will have to install the ‘Microsoft Access 2013 Runtime’ or ‘Microsoft Access Database Engine 2010 Redistributable’ and not ‘Microsoft Access 2016 Runtime’.

Another possibility is that you already have the Redistributable/Runtime files installed, but you are currently using the wrong version of SQL Image Viewer/SQL Blob Export/Access OLE Export.  All 3 products come in 32-bit and 64-bit versions, and are installed automatically on your computer.  If you only have the 32-bit Redistributable/Runtime files installed on your machine, you will need to use the 32-bit versions of our products; likewise if you have the 64-bit Redistributable/Runtime files installed.

You have never connected to the Access database on the same machine

To connect to the .accdb file, you will need to install the Microsoft Access Runtime/Redistributable files first.  You have the following options:

Usually, you can just download and install the latest version (Microsoft Access 2016 Runtime) to connect to your database successfully.

 

Merge multiple blobs into a single file

Some applications break up a file into smaller chunks before storing them into a table.  So for e.g. a 200 Kb file might be stored in 4 rows, each storing a maximum of 60 Kb, in the following layout:

ID  fileID  sequence  blobdata
1     201       1              (60 Kb)
2     201       2              (60 Kb)
3     201       3              (60 Kb)
4     201       4              (20 Kb)

When you export the blobs using SQL Image Viewer/Access OLE Export/SQL Blob Export, 4 files will be created using the default settings.  This is because those products treat each row as containing a separate file.

To export the 4 rows as a single file, you need to first select the ‘append to file‘ option for existing files.

This will cause the blob data to be appended to any existing file of the same name.

Next, you need to ensure that the 4 rows will all export to the same file name.  In our example above, we might use the fileID value as the name of the file, so all 4 rows will export to the same file.

Then, your SQL to export the blobs need to sort the rows so that the blobs get appended to the file in the correct sequence.  In our example, this means we need to sort the rows by the sequence value e.g.

SELECT fileID, blobdata FROM mytable ORDER BY sequence

Lastly, we need to ensure that in our output folder, there are no existing files of the same name, otherwise our blobs will get appended to those files.

That’s basically all you need to do to ensure that the blobs are exported in the correct sequence to a valid file.  In summary:

  • select the append to file option for existing files
  • use a naming convention that ensures the related blobs use the same file name
  • sort the rows in the correct sequence so that the blobs are appended in the correct order
  • before the export, ensure that no files of the same name are already in the output folder

Why is SQL Image Viewer not displaying details of my blobs

If you are using a third-party application to upload images and/or files into your database, and SQL Image Viewer cannot identify the image or file type, then there’s a high probability that your application has modified the data.

Examples of such applications include the MAZE School Information System and the Financial Edge system by Blackbaud.  We had a user who had the following data stored in their Financial Edge database.  In SQL Image Viewer, the following is displayed:

SQL Image Viewer is unable to identify the data that’s stored in the fields (they’re actually PDF files).  If we look at the data using the SQL Image Viewer hex viewer:

we can see that the OLE wrapper (or the original source data) begins at offset 32.  This means that Financial Edge has added 32 bytes of data to the beginning of the original file, which is why SQL Image Viewer does not recognize the file format.

To identify and extract the data correctly, we need to skip the first 32 bytes, so that we only retrieve the original source file.  In SQL Server, we can use the following syntax:

Now, SQL Image Viewer is able to identify the file type correctly.

Ok, admittedly not everybody knows what an OLE wrapper looks like, or any of the other file headers, which is why if SQL Image Viewer cannot identify your blobs, please send us a couple of samples to analyze.  We need the data exactly as stored in your database, so to extract the data, please perform the following steps and send us the resulting files.

Select the column containing the unidentified blob data.

Right click the mouse button to bring up the context menu, and select the ‘Save item’ option.

Enter a file name, save the blob data, and send the file to us at support@yohz.com.

The same issue applies to Access OLE Export and SQL Blob Export too.  If these products cannot identify the file type because the original files have an additional header, they will be exported with a .bin extension.  Please send us a couple of those .bin files to analyze, or you can also use SQL Image Viewer to retrieve the data and follow the steps above to send us the samples.

Exporting and extracting images and files from Microsoft Access databases

Using OLE Object column types, there are 3 ways you can store images and files in a Microsoft Access database, or in a database (e.g. SQL Server) used by a Microsoft Access front-end.

  • embedding

Embedding involves creating the image/file directly using the associated OLE Server application.  For example, if I chose to embed a bitmap image, Access will open Paint for me to create my bitmap image, and save that image into that field.

  • insert from a file

If you already have the image/file you want to store in your database, you can insert the file into your Access database directly using the ‘Create from File’ option.  Access then copies the file into the field.

  • link to a file

Similar to the above, but this time, the image/file is not stored in the database.  Access just creates a link to the external file, much like a hyperlink in your browser.

If you store your images/files using the first 2 methods, then Microsoft Access adds additional data to your image/file, so that it knows which application to use to open that particular image/file.  This means that if you extracted the data from your database, it will appear different from your original file.

For example, let’s insert an image into an OLE Object field.  The image file is 18.7 Kb in size.

Once inserted into the Access database, the size has increased to 19.192 Kb.

The increase is due to the additional data added by Access.  If you now extract the data as is from the database, it cannot be opened by Paint because of the additional data.  The PNG data is preceded by OLE headers.

This is a common issue faced by Microsoft Access users – when they want to extract images and files from OLE Object fields to their original format, there isn’t a way they can do this easily.  Every image/file has been modified by Access.  You have to open each image/file in Access, then save the item to disk manually.

This is the reason we created Access OLE Export.

In just 4 simple steps, Access OLE Export will extract and export your embedded images and files to disk, stripping out the additional data added by Access.  This means that the exported images and files can be opened ‘normally’, using the appropriate application.

If you require more control over what is exported, SQL Image Viewer is another option.  SQL Image Viewer allows you to inspect your data before exporting them, but requires that you be able to write SQL commands.

There may be situations where both products are unable to identify embedded images correctly.  This may be because the registered OLE Server for that content type is not yet supported.  In these cases, send us (at support@yohz.com) a sample of the embedded data, and we will add support for that OLE server type.

Download a FREE 14-day trial of Access OLE Export or SQL Image Viewer now to extract embedded objects from your Access databases the easy way.

You can purchase our products on this page.

See also:

 

Exporting images from OLE Object fields

→ This article refers to SQL Blob Viewer, which has now been renamed to SQL Image Viewer.  The techniques described in this blog is still applicable, as the functionality of the product remains the same.  Only the name has changed.

If you use OLE Object fields in your Access or SQL Server databases to store images, you know it’s convenient to just be able to click on the item and have Windows open the image using the registered viewer on your computer.  However, it becomes difficult to extract the images because Access adds additional OLE data to the stored images, thus changing their original form.

Take a Windows bitmap image,

and store it in an OLE Object field in a SQL Server linked-table.

The original file was 2,002,182 bytes in size, but has increased to 2,002,298 bytes when stored in the OLE Object field.  Access has added 116 bytes to the image.

and that the data stored in the field is different from the original bitmap file.

How can we then export this image?  One way is to open the table using Access, then double click on the data, and Access should then open the stored image in the registered OLE server for that image type, in our example Microsoft Paint.

However, this is a tedious process if we need to export a lot of images.  SQL Blob Viewer and Access OLE Export are two applications that we developed to easily export images and other data stored in OLE Object fields.  Exporting the items using SQL Blob Viewer or Access OLE Export is just a matter of writing the appropriate SQL query or selecting the right table.  SQL Blob Viewer is for users who are comfortable writing queries and want more control over how images are exported, while Access OLE Export is for users who just want to be able to select a table or write a simple query and export the images as is.

SQL Blob Viewer also displays a preview of the image when we query the table:

So if you have a ton of images that you need to export from OLE Object fields, give SQL Blob Viewer or Access OLE Export a try.

There may be situations where both products are unable to identify embedded images correctly.  This may be because the registered OLE Server for that content type is not yet supported.  In these cases, send us (at support@yohz.com) a sample of the embedded data, and we will add support for that OLE server type.

Extracting files and data from OLE Object fields

OLE Object fields are commonly used by applications using Access as the back-end database to store files and common document formats.  It is convenient because Windows handles how the files or documents are opened, modified, and saved via OLE servers.  However, it is difficult to extract the data from those fields because of the additional OLE information embedded together with your data.

For example, let’s create a table in Access, and store a simple Excel workbook, first as an embedded object, and second as an embedded file.  Our table structure is as follows:

We create the first record by directly embedding an Excel workbook.

For the second record, we simply attach an existing Excel workbook.

In Access, we can open both workbooks easily simply by double-clicking on them.  This is the OLE servers at work.

Now if we take a look at the size of the 2 records using SQL Image Viewer, we can see that the size of the embedded workbook is larger than the attached file.  The size of the attached file record is also larger than the original file size, because Access needs to add additional data to the file.

If you try to export the data as is, you will not be able to open the exported files, because the format itself is not Excel-compliant.  Both records in the OLE Object fields have had additional OLE wrappers added to them.

The usual way to extract the content is to open each item individually in Excel, and save them to files.  This is a tedious process if you have a lot of records you need to extract.

We have 2 products, SQL Image Viewer and Access OLE Export, that can remove the OLE wrappers for data stored in OLE Object fields, and export them to disk.

SQL Image Viewer is for technical users who are comfortable writing SQL queries to retrieve the required data.

Access OLE Export is for less technically inclined users who just want to be able to select a table and export their data quickly.

Both products can identify embedded Office document content, images, PDF content, Open Document content, and other common binary types.  Both products can also extract data from OLE Object fields used in other database engines like SQL Server, MySQL, Oracle, PostgreSQL, Firebird, SQLite, and ODBC data sources.

There may be situations where both products are unable to identify embedded content correctly.  This may be because the registered OLE Server for that content type is not yet supported.  For e.g. PDF files can have different OLE servers like Adobe Acrobat, Foxit PDF Reader. Nitro, etc.  In these cases, send us (at support@yohz.com) a sample of the embedded data, and we will add support for that OLE server type.

Download a FREE 14-day trial of SQL Image Viewer or Access OLE Export now, and see how easy it is to export your ‘trapped’ OLE Object data.

You can purchase our products on this page.