Create Flow Parameter

A flow parameter cannot be used in the following transformation steps or fields.

Transformations:

Parameter names can contain alphanumeric characters and spaces. in the following table, you can see how parameter names must be referenced in recipe steps.

paramRegion

$paramRegion
${paramRegion}

param Region

${param Region}

You can apply overrides to all parameter types, including flow parameters, at the flow level. An overridden value applies to all references of the parameter within the flow.

Steps:

This override value is applied to all references to the parameter in the flow.

Override values can be applied in multiple locations. Parameter values are evaluated in the following order of precedence (highest to lowest):

For more information, see Overview of Parameterization.

In this example, data is segmented by time zone. You must create a parameter to capture the following U.S. time zones, which must be specified explicitly:

'Hawaii'
'Alaska'
'Pacific'
'Mountain'
'Central'
'Eastern'

In your flow, you create the following flow parameter:

Name

paramTimeZone

Value

##UNSPECIFIED##

In the following transformation, the parameter value is inserted into a new column, paramTZ in your dataset:

Single row formula

${paramTimeZone}

'paramTZ'

You can also use the parameter as an input to a function. In the following example, the paramTimeZone parameter is merged with the values in the Store_Nbr to compute primary key storeId field:

Single row formula

merge([$paramTimeZone,Store_Nbr], '-')

'storeId'

Suppose you wish to create a flow parameter that contains multiple values. Typically, you must track these values through an array, such as the following containing a set of colors:

["red","white","blue","black"]

Flow parameters that are literals are String values only. As a workaround, you can define the above as a Wrangle .

Name

myColors

Value

`red|white|blue|black`

Within your recipe, you can test for the presence of a parameter value. In the following transformation, a value of true is set in the new column isBlue if the value of $myColors is blue:

Single row formula

MATCHES([blue], $myColors, true)

'isBlue'

Example - Integer parameter

Instead of segmenting the data by named time zone values, suppose your data is segmented by regions, which are numeric in number. Your flow parameter definition could look like the following:

Name

paramRegionId

Value

0

To use this flow parameter as an integer, you must reference it wrapped in the PARSEINT function, which evaluates the input value against the Integer data type:

Single row formula

PARSEINT(${paramregionId})

paramRegionId

In the column histogram for the paramRegionId column, you can verify that the value 0 is present. Set an override outside at the flow level to insert a different value in the column.

For more information, see PARSEINT Function.

Suppose you need to be able to pass a date into the execution of a recipe. If no date is passed in, then the current time is used. The variable is declared as follows:

Instead of segmenting the data by named time zone values, suppose your data is segmented by regions, which are numeric in number. Your flow parameter definition could look like the following:

Name

paramDate

Value

yyyy-mm-dd HH:MM:SS

You can use the following to insert the parameter value into your dataset. Note that the value is initially inserted as a String value, so the PARSEDATE function is used as a wrapper:

Single row formula

PARSEDATE(${paramDate},['yyyy-mm-dd HH:MM:SS'])

paramDate

For more information, see PARSEDATE Function.

If the inserted value is empty or null, you can insert the current timestamp:

execDate

IF((execDate == '') || ISNULL(execDate), NOW('UTC'), execDate)

In the above, the value in execDate is tested to see if it is either:

If so, the output of the NOW function is written. By default, this function returns the timestamp value at UTC time.

If there is a valid value, then it is written back to the column.

See NOW Function.

You can use the following to extract the time value from the parsed date param:

Single row formula

DATEFORMAT(execDate, 'HH:MM:SS')

Time

Since this value is not the parameter value specifically, the column name was listed simply as Time.