Row store databases organize data by row, with all columns in a row stored together on disk. They are mainly used for OLTP. A single column cannot be accessed without the entire row. Columnar databases organize data by each column, with all data in a field stored together on disk. They are mainly used for OLAP, allowing single columns to be accessed without their entire rows. OLTP databases like MySQL read entire rows even for single column queries, while OLAP databases like Snowflake only read the selected column for such queries.

1. Row vs Columnar Databases
Row Store Databases
● Store/organize data by row
● All the columns within a row are written/stored
together in the disk
● Mainly used for OLTP (Online transactional
processing )
● A single column/field cannot be accessed without
accessing the entire row

2. Row vs Columnar Databases
Columnar Databases
● Store/organize data by each field/column
● All the data within a field are written/stored
together in the disk
● Mainly used for OLAP (Online Analytical processing
)
● A single column/field can be accessed without
accessing the entire row

3. Row vs Columnar Databases
OLTP (Mysql,Postgresql,Oracle,Sql-Server) - “Select * from emp_details” will read the
entire row and “select Employee_id from emp_details” will also read the entire row .
OLAP (Snowflake,Bigquery,Redshift,Hive) - “Select * from emp_details” will read the entire
row and “select Employee_id from emp_details” will only read the selected column .
Employee_id Designation Department City
1 Software
Engineer
IT Bombay
2 Sales Executive Marketing Boston
3 Data Engineer BI Toronto