LET’S TALK DYNAMIC….SSIS EXPRESSIONS AND VARIABLES

Jason Yousef, MS MCITP MCTS

Why would you listen to me!• Sr. Database Engineer.• SQL BI & SQL Developer Trainer.• Started with SQL Server 7.

Agenda  Overview (Variables / Expressions). Variables – Data Types, scope, Namespace and naming conventions. Variables – Debugging using Breakpoints. Variables – User & System Variables using ‘Package Configurations’. Variables – Using .NET in a Script Task. (Control Flow) Variables – Using .NET in a Script Component. (Data Flow) Expressions and Dynamic SSIS. Expressions - Operators, Functions, Literals and Casting. Using the Expressions builder and the Expression Tester Application. Common String, Numeric, NULL, Conditional and Date & Time

examples. Q & A.

Overview Variables:

A place holder for your values, used to store and pass values between tasks and containers internally or between packages (child and parent packages).

Expressions: An expression is a combination of multiple

operators and functions and could reference multiple columns or variables to yield a single data value.

Variables

Right click (Designer) VariablesSSIS (Menu) VariablesView (Menu) OTHER WINDOWS Variables

Variables – Date Types

Data types are .Net data typesSSIS supports the following data types:

http://tinyurl.com/ssisDT

Boolean Byte Char

DateTime DBNull Double / Decimal

Int16 Int32 Object

SByte String UInt32

UInt64 Int64 Single

Variables – Scope , NameSpace

A way to organize your package and limit your variables to a certain task using Scopes or NameSpaces.

As variables’ names are unique, you can have the same name across multiple ‘Scopes’ or ‘Name spaces’

Variables – Naming Conventions

Name: Name of your variable. Preferable and suggested to use a meaningful Camel Case name, including its data type abbreviation, such as:

StrFName: For a string data type variable. IntTotalSales: For an integer data type variable, you

can also specify if it’s Int16, Int32 or Int64. (too much!) DTSalesDate: For a Date Time variable. BoolFileFound: For a Boolean variable, holds a flag (0

or1).

Variables – Breakpoints Debugging values.

Variables – Package Configurations

Read & write to system and User variables using ‘Package Configurations’

Variables – Reading / Writing Using .Net

Script Task (Control Flow)

Variables – Reading / Writing Using .Net

Script Component (Data Flow Task)

Variables using .NET

Demo

Expressions - Overview used to assign values to variables, update or populate

properties at run time, define constraints in precedence constraints, and provide the expressions used by the For Loop container.

The language is somehow similar to the curly braces languages (C++,C# or Java ).

Almost any task in SSIS, if not all, can use expressions to make its properties dynamic.

“Execute SQL Task” dynamic SQL query. “Derived Column” validate or assign value to a column. “Conditional Split” to split a column based on a specific condition. “Precedence Constraints“ direct the flow to a different route based on

a custom condition within the Control Flow.

Expression Builder SSIS 2005, 2008

SSIS 2012 Expression Task

Expression Editor & Tester Tool

http://expressioneditor.codeplex.com/

Expressions - Literals

Hard coded info that you provide when building expressions (Numeric, String and Boolean) to give more info about the expression’s value.

Numeric

Numeric literals checked for decimal points before getting casted to DT_UI4, and to DT_NUMERIC if there’s a decimal. To override use one of these suffixes.

Expressions - Literals

Boolean (True OR False) String

Escape Description

\n New Line

\b Backspace

\” Creates a Double Quotes

\t Tab

\\ Creates a backslash, used for URLs

Expressions - Operators

+ Add or (Concatenate)

- Subtracts or (Negates )

* Multiply / Divide

|| Logical OR && Logical AND

== Equal != Un Equal

? : Conditional < Less Than

> Greater Than <= Less Than or Equal

>= Greater Than or Equal

& Bitwise AND

Expressions - Casting Converts an expression from one data

type to a different data type. Implicit - Automatically Explicit – Using CAST

DT_BOOL True / False

DT_DBDATE Date

DT_DBTIMESTAMP

Date & Time

DT_I4 Four-byte, signed integer.

DT_DECIMALDT_NUMERIC

Decimal with precision and scale

DT_WSTR Unicode character string

Demo

Most commonly used expressions

Demo

SSIS 2012 New Expressions

Questions & Contact Info Email: JasonYousef@aol.com Blog: www.jasonyousef.com Twitter: @Huslayer

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Thanks for coming!