There is an Visual Studio SQL Server Database Project with such import lines inside .sqlproj file by default:
<PropertyGroup>
<VisualStudioVersion Condition="'$(VisualStudioVersion)' == ''">11.0</VisualStudioVersion>
<!-- Default to the v11.0 targets path if the targets file for the current VS version is not found -->
<SSDTExists Condition="Exists('$(MSBuildExtensionsPath)\Microsoft\VisualStudio\v$(VisualStudioVersion)\SSDT\Microsoft.Data.Tools.Schema.SqlTasks.targets')">True</SSDTExists>
<VisualStudioVersion Condition="'$(SSDTExists)' == ''">11.0</VisualStudioVersion>
</PropertyGroup>
<Import Condition="'$(SQLDBExtensionsRefPath)' != ''" Project="$(SQLDBExtensionsRefPath)\Microsoft.Data.Tools.Schema.SqlTasks.targets" />
<Import Condition="'$(SQLDBExtensionsRefPath)' == ''" Project="$(MSBuildExtensionsPath)\Microsoft\VisualStudio\v$(VisualStudioVersion)\SSDT\Microsoft.Data.Tools.Schema.SqlTasks.targets" />
Although there are no directories with SSDT for VisualStudioVersion 11.0, it opens correctly from Visual Studio. But when trying to load the project from .NET Core application using Microsoft.Build package it throws an error:
The imported project "D:\TestApp\TestApp\bin\Debug\netcoreapp3.1\Microsoft\VisualStudio\v11.0\SSDT\Microsoft.Data.Tools.Schema.SqlTasks.targets" was not found. Confirm that the expression in the Import declaration "D:\TestApp\TestApp\bin\Debug\netcoreapp3.1\Microsoft\VisualStudio\v11.0\SSDT\Microsoft.Data.Tools.Schema.SqlTasks.targets" is correct, and that the file exists on disk.
D:\Database1\Database1\Database1.sqlproj
The code for project loading looks like
var project = new Microsoft.Build.Evaluation.Project(@"D:\Database1\Database1\Database1.sqlproj");