How to connect microsoft sql binary large object fields (blob) with office365 sharepoint libraries

This "how-to-connect" documentation will explain the initial configuration of an example connection from an SQL Server to a Office365 / On-Premise SharePoint Library.


This guide presupposes that you have installed the Layer2 Cloud Connector and that you are familiar with its basic functionality. The Layer2 Cloud Connector User Documentation will provide you with all necessary information.




1. Preparing the SharePoint Library

2. Configuring the Layer2 Cloud Connector

2.1 Creating a new connection

2.2 Configuring the Data Entity 1

2.3 Configuring the Data Entity 2

2.4 Running your connection

3. Hints and known issues

3.1 Connection directtion

3.2 Limit of files per Blob fields

1. Preparing the SharePoint Library

In order to get our SharePoint files we will need to retrieve the SharePoint Online library URL.


Please copy the SharePoint library URL from your internet browser as shown below, as we will need it later for the connection string. 


SharePoint Layer2 Cloud Connector Connection Library URL


2. Configuring the Layer2 Cloud Connector

2.1. Creating a new connection

Create a new connection by using the Create New Connection option in the Actions pane (right-hand side). The new connection will appear at the bottom of the Connection Manager List (left-hand side). Click on your newly created connection to open the connection configuration settings.


Choose a meaningful name for your connection and replace the current "New Connection" Connection Title with it.


Although connections to can be bi-directional, an initial connection should always be uni-directional to assure that both data entities are identical before switching to bi-directional. Therefore, choose Left to Right as Direction. You can change this setting after your initial synchronization finished successfully.


Blob Layer2 Cloud Connector Connection Configuration

2.2. Configuring the Data Entity 1

We will now set up our Data Entities. Go to the data entity “Data Entity 1” to open the configuration settings.



Choose a Data Entity Title. It is recommended to give your entities meaningful names to maintain a good overview over the two entities.



Select the Data Provider for SharePoint(Layer2) from the data provider list.

You can search for SharePoint by typing into the selection box.



Blob Layer2 Cloud Connector Entity 1 Configuration


For the Connection String, we need the in step 1 mentioned information. You can copy the below connection string and adjust it to match your gathered information. Use the Verify Connection String option to evaluate if the provided connection string is valid.





  • "URL=https://your_sharepoint_library_url/Forms/AllItems.aspx;" this property defines the URL of your SharePoint library that will be addressed.
  • "Authentication=Microsoft_Modern;" this property will determine the authentication method used. The Microsoft_Modern authentication method connects to your SharePoint online tenant using the Microsoft ADAL auth method. This method will not work in case of federation, e.g. ADFS. For further authentication method you can consult the provider specifications linked above.




To check your data before synchronizing you can use the Preview Data option on the right-hand pane, it will provide you a pop-up window showing the data to be synced from your SharePoint library as shown below.



Blob Layer2 Cloud Connector Data Preview


2.3. Configuring the Data Entity 2


We are going to send the data to your Microsoft SQL Server table. It's required that you set up the SQL table prior to the next steps. Your table should contain matching columns according to your source entity.



Use the left-hand pane to switch to the data entity "Data Entity 2". We will be using the Data Provider for SQL Server for this setup. 



You can copy the below Connection String which contains the minimum of required properties to connect to your SQL server table.


Data Source=myServer; Initial Catalog=myDatabase; User Id=mySQL_User;


  • "Data Source;" this parameter defines the SQL server name.
  • "Initial Catalog;" this parameter defines the Database name where we will be connecting to.
  • "User Id;" with this parameter you specify the SQL user to use for connecting to your database. We recommend to use a dedicated SQL User while connecting to your SQL database instead of a AD user if supported, that's because the Microsoft ADO Provider for MS SQL is not allowing to specify credentials for an AD account to prevent the security risk of AD passwords being stored for applications accessing SQL.

Enter the password that belongs to the user account used in the connection string into the Password field. Save your changes by using the right-hand pane option Save Changes.



Blob Layer2 Cloud Connector Entity 2 Configuration


In the next step, we will configure our mapping settings. Click on the Mappings option on the left-hand pane. If your fields from SharePoint are named identical to the fields from your SQL table, the Enable Auto Mapping option will match those columns. Disabling this option allows you to match your columns as needed manually. We enabled auto-mapping in our setup. Save your changes by using the right-hand pane option Save Changes.


Blob Layer2 Cloud Connector Mapping


2.4. Running your connection

To run your connection switch back to the main connection configuration node and use the Run Now Button located on the bottom of the setup page. The Run Synchronization Toolbox will also display the synchronization process. 




Below is a data preview of the information we have accessed in our source entity:


Blob Layer2 Cloud Connector Data Source



This will be the result in our SQL Table after our initial successful synchronization:


Blob Layer2 Cloud Connector Data Destination



If you want to use a bi-directional synchronization, you can now switch your connection direction after our first initial synchronization run finished successfully. After adjusting the direction, you should check your Mappings settings again because some systems might include read-only columns that cannot be mapped directly.



We also recommend to choose a Conflict Resolution that matches your environments needs. You can find out more about the different conflict resolutions in our Layer2 Cloud Connector User Documentation.



3. Hints and known issues

Complex SharePoint fields like lookups, user or group picker etc. are generally supported. You have to make sure providing values that fit into the fields. If not possible, you can workaround by synchronizing text fields only and add your business logic using triggers and stored procedures (in SQL) or workflows (in SharePoint).

3.1. Connection Direction


This connection supports uni-directional as well as bi-directional synchronizations. Your query must be updatable for this (note that most joins are not). You also need to have write access rights to SQL for two-way synchronizations.


3.2. Limit of file per Blob fields

Please keep in mind that each BLOB field can handle up to 2 GB of data (except for Unicode type where its 1 GB) in MS SQL Server.




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