Article: http://www.zzzprojects.com/entity-framework-extensions/docs/tutorials/licensing

entity-framework-extensions-docs-tutorials-licensing-example-1.cs

<appSettings>
	<add key="Z_EntityFramework_Extensions_LicenseName" value="[licenseName]"/>
	<add key="Z_EntityFramework_Extensions_LicenseKey" value="[licenseKey]"/>
</appSettings>

entity-framework-extensions-docs-tutorials-licensing-example-2.cs

string licenseName = //... PRO license name
string licenseKey = //... PRO license key

Z.EntityFramework.Extensions.LicenseManager.AddLicense("[LicenseName]", "[LicenseKey]");

entity-framework-extensions-docs-tutorials-licensing-example-3.cs

// CHECK for default provider (SQL Server)
if(!Z.EntityFramework.Extensions.LicenseManager.ValidateLicense())
{
   throw new Exception("Invalid License!");
}

// CHECK for a specific provider
if (!Z.EntityFramework.Extensions.LicenseManager.ValidateLicense(ProviderType.MySql))
{
   throw new Exception("Invalid License!");
}