Read Committed Isolation

Read Committed Isolation is the most basic, weak level transaction Isolation mechanism provided by databases that support transactions. It is the default setting in Oracle 11g, PostgreSQL, SQL Server 2012, MemSQL, and many other databases.

This isolation level makes two guarantees:

• When reading from the database, you will only see data that has been committed (no Dirty Reads).
• When writing to the database, you will only overwrite data that has been committed (no Dirty Writes).