SQL vs. NoSQL Databases & Properties

NoSql databases have been increasing in popularity, so let’s layout the differences between SQL and NoSql, and why you would choose one database type over the other.

SQL characteristics (ie: PostgreSql)

DB contains tables with rows

static schema, fixed data types

add/ delete fields updates all rows

has foreign keys to set relationships

supports ACID transactions

normalized to reduce redundancy

DB scales vertically (more resources)

NoSql characteristics (ie: MongoDB)

DB contains collections with documents

dynamic schema, dissimilar data types

can add/ remove fields dynamically

documents can embed other documents

supports atomic operations for single docs

denormalized to increase read speeds

DB scales horizontally (uses more servers)

Choosing Database Type:

Choose SQL if the data needs ACID properties, data reads/ writes require transactions, data needs to be aggregated or analyzed, or types of data (columns) are mostly static.

Choose NoSQL if data needs to scale easily, eventual data consistency is ok, or the types of data (columns) change often.