AWS Databases Essentials

Amazon RDS is a managed database service customers can use to create and manage relational databases in the cloud without the operational burden of traditional database management.

• 1($) provide a balance of compute, memory, and network resources. They are a good choice for many database workloads.
• 2($) accelerate performance for workloads that process large datasets in memory.
• 3($) provide a baseline level of CPU performance with the ability to burst above the baseline.

A table in DynamoDB is a collection of 1($), and each 2($) is a collection of attributes.

1. DynamoDB stores data in 1($) which is a collection of data.
2. Each table contains zero or more 2($). An item is a group of attributes that is uniquely identifiable among all other items. 
3. An item is composed of one or more 3($).  An attribute is a fundamental data element, something that does not need to be broken down any further.
4. When you create a table, in addition to the table name, you must specify the 4($) of the table. 
5. You can create one or more 5($) indexes on a table. 
6. DynamoDB 6($) is an optional feature that captures data modification events in DynamoDB tables. The events are near real time and occurs when an item is created, updated, or deleted.
7. One 7($) capacity unit (RCU) represents one strongly consistent read per second, or two eventually consistent reads per second, for an item up to 4 KB in size.
8. One 8($) capacity unit (WCU) represents one write per second for an item up to 1 KB in size.
9. 9($) is the action of limiting the number of requests that a client can submit to a given operation in a given amount of time. 
10. DynamoDB has two 10($) capacity modes for processing read/write transactions on your tables (On demand and Provisioned).

Indexes are local or global. A 1($) secondary index has the same partition key as its base table but a different sort key. Use 2($) secondary indexes to query attributes outside the primary key of your original table.