Karen Lopez @datachick #TEAMDATA

GREAT SCOTT!Working with all those weird datatypes

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@datachick@ERStudio

Karen López

Karen has 20+ years of data and information architecture experience on large, multi-project programs.

She is a frequent speaker on data modeling, data-driven methodologies and pattern data models.

She blogs at community.embarcadero.com, datamodel.comand Dataversity.net

She wants you to love your data.

Logistics…

Use Q&A for formal questions – ask at any

time

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Plan for Today

Types of Data Types

The Outlier Data Types

Working with Data Types

10 Tips for Working with Data Types

Poll: Who are you?

Poll: Which RDBMSs Do You Support?

Datatypes

Why do we need them?What types of datatypes are there?

Datatypes aren’t

just formats

Datatypes are

also about

data quality

Datatypes are

also about

PERFORMANCE

Note…

Today’s focus is mostly on physical data types…

….but I do have some thoughts on logical data types as well

Types of Datatypes*

predefined data types

constructed types

user-defined types

ISO: 9075

Data types

Understand your data type taxonomies, by RDBMS and version.

IBM DB2

Understand the lingo

Data type names

Data type syntax

Data type gotchas

The Basic Datatypes

Strings

Numeric

Boolean

Dates and Times

Interval

ISO: 9075

Fancy Datatypes

• HIERARCHYID

• Spatial data types (GEOMETRY, GEOGRAPHY, more)

• XML

• JSON < NEW!!!!! FANCY!!!

• PERIODs

• MONEY

• Spatial temporal data types (a special one)

Hierarchies

Meet JSON

Javascript Object Notation

JSON support arrays and variable data items

Much like XML in theory (shredding, overuse, popular )

https://docs.mongodb.org/getting-started/shell/import-data/

Periods

Data type for storing an opening and closing date (or time) period

Has special operators and functions to help work with the data

Importantly, an “until closed” end period

https://developer.teradata.com/database/articles/exploring-teradata-13s-period-data-type

Spatial data types

Special functions

Meet needs for shapes and lines

Geospatial Data in SQL Server. (2015, May 14). Wikibooks, The

Free Textbook Project. Retrieved 18:21, November 10, 2015

from https://en.wikibooks.org/w/index.php?title=Geospatial_Data_i

n_SQL_Server&oldid=2958376.

Money (and other specialized data types)

Special use cases

Special limiations

Limited cross-platform support

Often limitations are not well known

http://www.postgresql.org/docs/9.4/static/datatype-money.html

http://www.postgresql.org/docs/9.4/static/datatype-net-types.html

Dates and Times

Various “precisions”

Some, not all, RDBMSs support WITH TIMEZONE

Conversion compatibilities

ISO 9075

Host Implementation Gotchas

TIMESTAMP

Dates and Times WITH TIMEZONE

TINYINT

BIT

And more….

Other Gotchas

Conversion Compatibilities

Performance of conversions

Foreign key consistency

NULLability

https://msdn.microsoft.com/en-us/library/ms191530.aspx

User Defined Data Types

http://www.datamodel.com/index.php/20

14/04/01/sql-server-2014-new-datatype/

Iterative Data Modeling

How do we set data types?

Data architects must work with DBAs, Devs, end users to finalize datatypes

Deciding on Datatypes

Data profiling

Awareness of options

Confirmation of cost, benefit, risk

Urban myths

Testing and benchmarking

What about logical data types?

They are just as important

Many of our thoughts today apply

We should stive to keep them simple

Logical data types for meaning

Yet….

Logical/Physical data type mapping

Other Modeling Gotchas

10 Tips for using the right datatypes

1.Learn all the datatypes available to you, by RDMS and version

2.Read the pros and cons of each

3.Create user defined datatypes that provide benefits to more than just the data modeler

4.Understand datatype compatibilities

5.Know the business case for longer datatypes

10 Tips for Data Modelers

6. Be prepared to defend the use of the correct datatype

7. Size matters: know why

8. Stop using deprecated data types. Really. Just. Stop.

9. Monitor RDBMs upcoming features

10.Request enhancements if your tools don’t support an RDBMS datatype.

RDBMS resources

SQL Server Books On Line (MSDN)

IBM DB2 (z/OS and LUW) Knowledge Center

Teradata Online Library

Oracle Database Online Library

…plus all the others…

Community

community.embarcadero.com

Thank you, you were great.

Let’s do this again some time!

Karen Lopez @datachick