Database Design Tips | Choosing the Best Database in a System Design

Key Parameters

Title	Remarks
⭐ Query Patterns	How complex are your query patterns? - Do you just need retrieval by key, or also by various other parameters? Do you also need fuzzy search on the data?
Consistency	Is strong consistency required (read after write, especially when you switch writes to a different data-center) or eventual consistency is OK?
Storage Capacity	How much storage capacity is needed?
Performance	What is the needed throughput and latency?

Title	Category	Remarks
SQL vs NoSQL	General	Terms Comparison - SQL vs NoSQL
All Databases list	General
DB Scalability Techniques	General
OLTP vs OLAP	General
Sharding of the database	Sharding	To scale the data store horizontally (& improve write scalability), shard the databases using consistent hashing technique.
Partitioning Key Tips	Sharding	Decide partition key carefully (to prevent hot partition problem).
DynamoDB vs MongoDB vs Casandra	NoSQL DB
SQL Tunning	SQL DB	Tune queries, to improve performance of SQL Queries.

Tips	Description
Data that is accessed together should be stored together	Instead of distributing related data items across multiple tables, you should keep related items in your NoSQL system as close together as possible.
Vertical partitioning	Breaks items into multiple items using partition key & sort key. - Read more
Use sort order	All items with the same partition key value are stored together, in sorted order by sort key value.
Distribute Queries	Design data keys to distribute traffic evenly across partitions as much as possible, avoiding hot spots.
Use secondary indexes	By creating specific secondary indexes, you can enable different queries than your main table can support, and that are still fast and relatively inexpensive.