Data Models Flashcards
What does a data model do?
A data model provides the mapping between an application entity and how it is stored in a system.
What does the Object-relational model provide?
It provides a way to map classes (from object oriented systems) to a schema (tables, relations, etc)
What does the Document model provide?
Document model encapsulates and encodes data in a semi structured standard (Json, XML)
What do Document Models struggle with?
They struggle with many-to relationships and implement join functionality less efficiently
Why would a Graph Like model be used?
It is suited for complex many-to-many relationships that are challenging for relational and document models.
How is a Graph Like Model structured?
Entities are represented as nodes and the relationship as an edge.
What are the features of NoSQL Databases?
Uses Not Only SQL to interact with it, applies non-relational storage and retrieval of data, focuses on simplicity and scalability.
What are the two types of Document Store?
Key-Value Store, Wide Column Store.
How does a Key-Value Store work?
Data is stored in associative arrays, with each object being represented by a set of key value pairs.
How does a Wide Column Store Work?
It is a Two Dimensional Key Value Database where data is grouped in rows, and the names and formats of columns can vary form record to record
What is the use case of Schema Flexability?
Most document databases do not enforce a schema and the structure is implicit and defined when the data is read by an application. Allows for more efficient changes of data format.
What is the CAP Theoram?
If using a distributed system only two of three can be chosen: Consistency, Availability, Partition Tolerance.
What id Data Locality?
A document is usually stored in a single continuous string
