Data Science - Revision history

Tedyun at 02:50, 3 September 2013

2013-09-03T02:50:07Z

2013-09-03T02:49:03Z

2013-09-03T02:46:20Z

Relational Algebra

2013-09-03T02:45:08Z

Relational Algebra

2013-09-03T02:44:40Z

2013-09-01T04:59:06Z

Data Model

2013-09-01T04:58:56Z

Data Model

2013-09-01T04:56:39Z

2013-09-01T04:54:06Z

2013-08-19T03:11:01Z

The Three V's of Big Data

@@ Line 20: / Line 20: @@
 === Relational Algebra ===
 Operations
 * Union $\cup$, intersection $\cap$, difference $-$

← Older revision		Revision as of 02:49, 3 September 2013
Line 28:		Line 28:
	* (Extended RA) Grouping and aggregation $g$		* (Extended RA) Grouping and aggregation $g$
	* (Extended RA) Sorting $t$		* (Extended RA) Sorting $t$
		+
		+	==== Join ====
		+	* Equi-join $\bowtie_{A=B}$
		+	* $\theta$-join $\bowtie_\theta$

@@ Line 22: / Line 22: @@
 Operations
 * Union $\cup$, intersection $\cap$, difference $-$
-* Selection $s$
+* Selection $\sigma$
 * Projection $\Pi$
 * Join $\bowtie$

@@ Line 25: / Line 25: @@
 * Projection $\Pi$
 * Join $\bowtie$
-* Duplicate elimination $d$ (Extended RA)
+* (Extended RA) Duplicate elimination $d$
-* Grouping and aggregation $g$ (Extended RA)
+* (Extended RA) Grouping and aggregation $g$
-* Sorting $t$ (Extended RA)
+* (Extended RA) Sorting $t$

← Older revision		Revision as of 02:44, 3 September 2013
Line 18:		Line 18:
	* Scale		* Scale
	* Flexibility		* Flexibility
		+
		+	=== Relational Algebra ===
		+	Operations
		+	* Union $\cup$, intersection $\cap$, difference $-$
		+	* Selection $s$
		+	* Projection $\Pi$
		+	* Join $\bowtie$
		+	* Duplicate elimination $d$ (Extended RA)
		+	* Grouping and aggregation $g$ (Extended RA)
		+	* Sorting $t$ (Extended RA)

@@ Line 12: / Line 12: @@
 What is a database? '''A collection of information organized to afford efficient retrieval.'''
 Why do we need a database?
 * Sharing

← Older revision		Revision as of 04:58, 1 September 2013
Line 12:		Line 12:

	What is a database? '''A collection of information organized to afford efficient retrieval.'''		What is a database? '''A collection of information organized to afford efficient retrieval.'''
		+	Why do we need a database?
		+	* Sharing
		+	* Data model enforcement
		+	* Scale
		+	* Flexibility

← Older revision		Revision as of 04:56, 1 September 2013
Line 10:		Line 10:
	* Constraints		* Constraints
	* Operations		* Operations
		+
		+	What is a database? '''A collection of information organized to afford efficient retrieval.'''

← Older revision		Revision as of 04:54, 1 September 2013
Line 4:		Line 4:
	* Velocity: number of rows/bytes ''per unit time''		* Velocity: number of rows/bytes ''per unit time''
	(Veracity: Can we trust this data?)		(Veracity: Can we trust this data?)
		+
		+	=== Data Model ===
		+	Three components:
		+	* Structures
		+	* Constraints
		+	* Operations

← Older revision		Revision as of 03:11, 19 August 2013
Line 3:		Line 3:
	* Variety: number of columns/dimensions/sources		* Variety: number of columns/dimensions/sources
	* Velocity: number of rows/bytes ''per unit time''		* Velocity: number of rows/bytes ''per unit time''
		+	(Veracity: Can we trust this data?)