NoSQL Cheng Lei Department of Electrical and Computer Engineering University of Victoria Mar 05, 2015

Outline ❖ Why NoSQL? ❖ Aggregate Data Model ❖ Distribution Model

❖ Why NoSQL? ❖ Aggregate Data Model ❖ Distribution Model

Why NoSQL ? Impedance mismatch the difference between the relational model and the in-memory data structures Working on clusters: More sufficiently Schemaless Opensource

❖ Why NoSQL? ❖ Aggregate Data Model ❖ Distribution Model

Aggregate Data Model Aggregate: an aggregate is a collection of related objects treated as a unit.

Key-Value Data Model The aggregate is opaque to DB, just some big blob of mostly meaningless bits Access aggregates by lookup based on the keys

Document Data Model The aggregate is built by the structure of the document

Column-Family Stores It is a two-level map The first key is often described as a row identifier Second-level values are referred to as columns

❖ Why NoSQL? ❖ Aggregate Data Model ❖ Distribution Model

Distribution Models Single server Sharding Master-Slave Replication Peer-to-Peer Replication Combining Sharding & Replication

Sharding Putting different parts of data onto different servers

Master-Slave Replication One node as the master, controlling the operations on the rest nodes All changes are made to the master The master propagates the changes to slaves The slave node can be assigned as the master if master fails

Peer-to-Peer Replication Reads and writes on each single server Each node synchronizes the writes with each other Consistency issues may occur

Combining Sharding & Replication Master-Slave replication &sharding Multiple masters Each data item only has single master Peer-to-Peer replication & Sharding Make 3 copies of node data

Thank You!!!