SQL Server 2016 introduced a new type of user table that is called System-versioned Temporal Table to keep a full history of data changes.

This is a very good addition to the SQL Server 2016 because to track data change history is always an important task for a big transactional system.

SQL Server already provides few features to track data change like Change Data Capture (CDC), SQL Server Auditing, can create a manual DDL Trigger.

Now, SQL Server 2016 System-versioned temporal table which is something good and very easy to implement on a specific table.
You can audit all data changes and can perform require analysis on it. In Case of invalid delete or update, you can recover your data.

Rules and Requirements:

• Can create your table using SYSTEM_VERSIONING=ON
• Define your history table name HISTORY_TABLE = TableName, which tracks data change history. (It creates automatically).
• Must define two additional columns [ValidFrom] and [ValidTo] with default ROW START and ROW END and must refer to as SYSTEM_TIME period columns.
• Must have a Primary key column.
• Same number of column and structure between both the tables.

Full demonstration:

Create a sampel System Version Table:

CREATE TABLE tbl_Students
(
	StudID INT PRIMARY KEY
	,StudName VARCHAR(50)
	,StudClass CHAR(1)
	,ValidFrom DATETIME2 (2) GENERATED ALWAYS AS ROW START  
	,ValidTo DATETIME2 (2) GENERATED ALWAYS AS ROW END  
	,PERIOD FOR SYSTEM_TIME (ValidFrom, ValidTo)  
) WITH (SYSTEM_VERSIONING = ON (HISTORY_TABLE = dbo.tbl_StudentsHistory));  
GO

Insert few sample records:

INSERT INTO tbl_Students 
(StudID,StudName,StudClass)
VALUES (1,'Roy','A'),(2,'Bony','B'),(3,'Mahi','C')
,(4,'Maria','A'),(5,'Ron','B'),(6,'Murey','C')
GO

Execute few DML statements:

UPDATE tbl_Students SET StudClass = 'B'
WHERE StudID = 4;
GO

DELETE FROM tbl_Students WHERE StudID = 2
GO

Check the result of both tables:

SELECT *FROM tbl_StudentsHistory

StudID  StudName      StudClass ValidFrom                   ValidTo
------- ------------- --------- --------------------------- ---------------------------
4       Maria             A         2017-01-06 05:47:23.73      2017-01-06 05:48:54.43
2       Bony              B         2017-01-06 05:47:23.73      2017-01-06 05:50:12.52


SELECT *FROM tbl_Students

StudID  StudName        StudClass ValidFrom                   ValidTo
------- --------------- --------- --------------------------- ---------------------------
1       Roy                 A         2017-01-06 05:47:23.73      9999-12-31 23:59:59.99
3       Mahi                C         2017-01-06 05:47:23.73      9999-12-31 23:59:59.99
4       Maria               B         2017-01-06 05:48:54.43      9999-12-31 23:59:59.99
5       Ron                 B         2017-01-06 05:47:23.73      9999-12-31 23:59:59.99
6       Murey               C         2017-01-06 05:47:23.73      9999-12-31 23:59:59.99

SQL Server provides different types of database auditing option like: CDC, Database Audit.
Recently, I have shared one article about, change your database DDL changes using Encrypted DDL triggers.

SQL Server: Encrypted DDL Trigger to Track all Database Changes

Database Administrators are responsible for database security and Periodically, They have to track all the database related changes and make sure that everything is working fine.

But still sometimes, I used to track database changes from the SQL Server log files using fn_dblog().
I am sharing one way to find a person who dropped a table and also can get the name of that dropped table without enabling any auditing option of SQL Server.

Script to find the log of dropped objects:

Using this script, you can find a list of dropped tables and login name information, but you cannot get table name directly.
You can find the transaction id for each record and using this transaction ID, you can find the table name.

SELECT 
	[Transaction Id]
	,[Begin Time]
	,SUSER_SNAME ([Transaction SID]) AS [LoginName] 
FROM fn_dblog (NULL, NULL)  
WHERE [Transaction Name] = N'DROPOBJ';

Find Table name using TransactionID:

SELECT TOP 1 
	[Lock Information] 
FROM fn_dblog (NULL, NULL)  
WHERE [Transaction Id] = '0000:0015d6b3'  
AND [Lock Information] LIKE '%SCH_M OBJECT%';

The result:
To get the table name, you can copy the number and search into sys.objects table.

HoBt 0:ACQUIRE_LOCK_SCH_M OBJECT: 8:1015674666:0

Find your dropped table:
Please do not start to search your dropped table in your current database because Table already dropped.
You must restore the last backup of the database and you should search your dropped table in that database.

SELECT *FROM sys.objects 
WHERE Object_ID ='1015674666'