How to simulate a situation when non-empty Transaction Log file will be added to the SQL Server Full Database backup file I created a test database &quot;StoredData&quot; with a single table:
CREATE DATABASE StoredData 
 ON  PRIMARY 
( NAME = N'StoredData', FILENAME = N'C:\Program Files\Microsoft SQL Server\MSSQL14.MSSQLSERVER\MSSQL\DATA\StoredData.mdf')
 LOG ON 
( NAME = N'StoredData_log', FILENAME = N'C:\Program Files\Microsoft SQL Server\MSSQL14.MSSQLSERVER\MSSQL\DATA\StoredData_log.ldf')
GO

ALTER DATABASE [StoredData] SET RECOVERY FULL

GO

USE StoredData
GO

CREATE TABLE dbo.Users
(
    Id INT NOT NULL,
    Name NVARCHAR(50) NOT NULL
)

Then I inserted 3 records into that table:
INSERT INTO dbo.Users (Id, Name)
VALUES (1, 'John'),
       (2, 'Giovanni'),
       (3, 'Anna')

After that I run this query to have some active transactions:
DECLARE @i INT = 0;

WHILE @i &lt; 1000
BEGIN

    IF(@i%10 = 0) BEGIN TRAN

    INSERT INTO dbo.Users
    SELECT TOP 10 * FROM dbo.Users

    WAITFOR DELAY '00:00:01';  

    IF(@i%10 = 9) COMMIT

    SET @i = @i+1
END

During the last query execution I'm trying to do full database backup:
BACKUP DATABASE StoredData 
TO  DISK = N'C:\Program Files\Microsoft SQL Server\MSSQL14.MSSQLSERVER\MSSQL\Backup\StoredData_FullRecovery_Uncompressed.bak' 
WITH FORMAT, NO_COMPRESSION

Then I'm looking into the backup file content:
RESTORE FILELISTONLY 
FROM DISK = 'C:\Program Files\Microsoft SQL Server\MSSQL14.MSSQLSERVER\MSSQL\Backup\StoredData_FullRecovery_Uncompressed.bak'

And I'm getting zero log file inside backup:
LogicalName:       StoredData_log 
BackupSizeInBytes: 0
There are two things going on here:
1: The database is effectively in simple recovery mode when doing your modifications, since you never did your first full backup after creating the database.
2: The column BackupSizeInBytes seems to be 0 for all ldf files, quite simply, even when there is log records in there. The documentation is vague for this column, so it difficult to say whether it is by design or not.