RDBMS vs MongDB

RDBMS	MongoDB
Database	Database
Table	Collection
Tuple/Row	Document
column	Field
Table Join	Embedded Documents
Primary Key	Primary Key ( _id )

Mysqld/Oracle	mongod
mysql/sqlplus	mongo

Checkpoint information

 
SQL> select NAME , CHECKPOINT_CHANGE# , CURRENT_SCN from v$database ;

CHECKPOINT_CHANGE#  --->  Last SCN checkpointed
CURRENT_SCN         --->  Current SCN of database

NAME  CHECKPOINT_CHANGE# CURRENT_SCN
--------- ------------------ -----------
SUMIT     1902688 1903608

SQL> select first_time,first_change#,sequence# , status from v$log ;

FIRST_TIME    --> Time of the first SCN in the log
first_change# --> Lowest system change number (SCN) in the log

FIRST_TIME    FIRST_CHANGE#  SEQUENCE# STATUS
------------------- ------------- ---------- ----------------
01-2016-10 07:18:16  1902580  13 ACTIVE
01-2016-10 07:25:24  1903604  14 CURRENT
01-2016-10 06:02:51  1898715  12 INACTIVE

SQL> select CHECKPOINT_CHANGE# , CHECKPOINT_TIME  from V$DATAFILE ;

CHECKPOINT_CHANGE#  -----> SCN at last checkpoint
CHECKPOINT_TIME     -----> Timestamp of the checkpoint#

CHECKPOINT_CHANGE# CHECKPOINT_TIME
------------------ -------------------
  1902688 01-2016-10 07:21:02
  1902688 01-2016-10 07:21:02
  1902688 01-2016-10 07:21:02
  1902688 01-2016-10 07:21:02
  1902688 01-2016-10 07:21:02
  1902688 01-2016-10 07:21:02

6 rows selected.

SQL> select CHECKPOINT_CHANGE# ,CHECKPOINT_TIME,CHECKPOINT_COUNT from V$DATAFILE_HEADER ;

CHECKPOINT_CHANGE# -----> Datafile checkpoint change#
CHECKPOINT_TIME -----> Datafile checkpoint timestamp

CHECKPOINT_CHANGE# CHECKPOINT_TIME     CHECKPOINT_COUNT
------------------ ------------------- ---------------------------- -------------------------- --------------
  1902688 01-2016-10 07:21:02    190
  1902688 01-2016-10 07:21:02     15
  1902688 01-2016-10 07:21:02    190
  1902688 01-2016-10 07:21:02     30
  1902688 01-2016-10 07:21:02     27
  1902688 01-2016-10 07:21:02    188

6 rows selected.