Migrating to multitenancy
You can choose to migrate your Business Central solution to a multitenant deployment architecture where you maintain a single application that is used by two or more companies that store their data in separate databases.
This can make maintenance of your solution easier if you support multiple customers with the same application functionality.
Tenants and companies
When you upgrade your application and the data to Business Central, you have a database that has the same number of companies as you had before the upgrade. This database is considered a tenant. This doesn't mean that you have to turn your solution into a multitenant deployment. But it means that you can if you want to.
For example, your Business Central deployment in the earlier version consisted of a database that has 20 companies. In other words, you support 20 companies that all share the same application functionality. In this example, the companies are separate companies that have nothing to do with each other except that they're supported by you in one database. In Business Central, you can choose to extract the application-wide tables into a separate database and keep the data for all 20 companies in the original database. This becomes a single-tenant business data database. Then, you can choose to split the business data database into one for each company so that you run a truly multitenant environment. The application is stored separately in the application database, and you maintain application functionality centrally. When you modify the application, you make the changes available to one tenant at a time. As a result, if something goes wrong, all other tenants aren't affected.
Compare this to earlier versions of Business Central where a database could contain several companies. These companies could be related or not, but they would all use the same application and write to the same database. Also, when you modified the application, it would affect all companies immediately. So if something went wrong, all companies would be affected.
Note
The email logging functionality in Business Central requires the Business Central Server service account to have access to the Exchange server. But in a multitenant deployment, this is not always possible.
In multitenant deployments of Business Central, permission sets are stored centrally in the application database, so only the administrator of the central application can add, remove, or modify permission sets. Instead, the tenants can use user groups to manage permissions.
Migration process
If you decide to move to a multitenant architecture, you must complete the following steps:
Move the tables that describe the application to a separate database. For more information, see Separating Application Data from Business Data.
After this step, you have two databases: an application database and a business data database.
Split the business data database into one for each company. For more information, see Creating Tenants from Companies.
After this step, you have an application database and a business data database for each company in the original database. The company-specific business data databases are tenants, and your solution is multitenant.
If you want to move back to storing application tables and business data in a single database, you can use the Business Central Windows PowerShell cmdlets to merge the databases. For more information, see Merging an Application Database with a Tenant Database.
Related information
Separating Application Data from Business Data
Creating Tenants from Companies
Upgrading the Application Code
Upgrading the Data
Upgrading to Business Central