Databases

Yuriy GutsR&D Engineer

yuriy.guts@eleks.com

Summer School 2012

Why do we need databases?

Summer School 2012

Try answering this question:

Why do we need computers?

???

Why do we need databases?

Summer School 2012

Computer Science

Is it a science?Is it about computers?

“Datalogy” — Peter Naur, 1961

Navigational databases (1960-s)

Summer School 2012

Relational databases (1970-s)

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Relational Algebra 101

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Set Union Natural Join

Set Intersection Equi-Join

Cartesian Product Semi-Join

Projection Anti-Join

Selection Division

Rename Outer Join

Entity Relationship & (De)Normalization

Summer School 2012

• One-to-one• One-to-many• Many-to-many

Normal Forms

• 1NF• 2NF• 3NF• BCNF

• 4NF• 5NF• DKNF• 6NF

Association Cardinality

Structured Query Language (SQL)

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Storage: B-Tree, Indexing

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Database as a Concurrent Storage

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A Atomicity

C Consistency

I Isolation

D Durability

Although transactions can have different isolation levels!

Lower levels can improve performance, but with a price (side effects)

Transaction Properties (“ACID”)

Relational DBMS Products

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Object-Relational Mapping (ORM)

Object-Relational Mapping (ORM)

ORM: Example (Entity Framework)

ORM: Design Approaches

Database First

Model First

Code First

Does life exist beyond RDBMS?

Multidimensional Data

• Data Analysis• Performance Measurement• Enterprise Reporting• Knowledge Management• Data Mining

Business Intelligence

NoSQL Databases

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Key-Value Store Document Store Multivalue Store

Graph Store Object Database RDF Database

Brewer Theorem (“CAP Theorem”)

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C Consistency

A Availability

P Partition Tolerance

A distributed computer systemcannot provide all three of the following:

Common case: “Eventual Consistency” databases

NoSQL Database Products

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Some More DB Types

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Active Embedded Knowledge

Cloud Federated Parallel

Data Warehouse Hypermedia Real-time

Distributed Hypertext Spatial

Document In-memory Temporal

Q & A

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???yuriy.guts@eleks.com

Thank you!

Summer School 2012