XPath for Cost Based Estimating
Fusion 08
Duncan Seibert
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Introduction
• XPath, as implemented by ePace, provides the
user with a tool to define a value for an
operation that is custom to their shop. Typically
the XPath expression is used to provide a
quantity that is used as the basis for a table
lookup or is multiplied by a flat rate to provide
either time or material usage.
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Abstract
• XPath is an expression language that allows the
processing of values conforming to the data model
defined in XQuery/XPath Data Model (XDM). The data
model provides a tree representation of XML data
sources as well as atomic values such as integers,
strings, and booleans, and sequences that may contain
both references to nodes in an XML data source and
atomic values. The result of an XPath expression may
be a selection of nodes from the input data sources, or
an atomic value, or more generally, any sequence
allowed by the data model. The name of the language
derives from its most distinctive feature, the path
expression, which provides a means of hierarchic
addressing of the nodes in an XML tree.
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Session Contents
1. Determine what the calculation needs to do.
2. Determine field names.
3. Determine the data type of the result field.
4. Determine how you will cost your operation based on the data type.
5. Find your fields relative to the current object.
6. Write your expression in simple terms.
7. Write your expression in XPath.
8. Test your expression.
9. Enter your expression into ePace.
10. Use your expression.
11. Syntax.
12. Examples.
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1. Determine what the calculation
needs to do.
• The first step is to determine what the formula
needs to accomplish.
• Determine which fields hold reference values
and what conditions need to be met first.
• Then determine the formula to arrive at the
desired results.
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1. Determine what the calculation
needs to do.
• The first step is to determine what the formula needs to
accomplish. Determine which fields hold reference
values and what conditions need to be met first. Then
determine the formula to arrive at the desired results.
• Example:
To preflight a file, allow 15 minutes to review the job jacket, create
a job directory on the storage server, transfer the file into the
director and open the file in preflight software. Then allow 6
seconds per page to check the preflight, 10 pages per minute,
600 per hour.
• Formula = .25 + (number of pages / 600). Result is in
decimal hours.
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2. Determine field names.
• There are two way to determine the names of
the fields to use.
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2. Determine field names.
• There are two way to determine the names of
the fields to use.
• One is to go to Administration -> System
Configuration -> Object Model -> Object Model
Browser, select the target object, click on the
Fields tab and find the fields you need.
• This will also show any Calculated Fields that
may not appear on a screen but will make your
statement easier.
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2. Determine field names.
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2. Determine field names.
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2. Determine field names.
• The other way is to open an estimate and go to details.
• Go to Administration -> Toggle Debug Mode.
• This will show you the names of the fields in the Object
Model (dataset).
• Drill into an operation like the one you will be
describing, in our example a Prepress Operation.
• In the label area of the field of interest there will be a
name. Hover over the field to show the information. It
will appear as:
EstimatePrepressOp, expr: ../@quantityOrdered
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2. Determine field names.
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2. Determine field names.
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2. Determine field names.
• Example:
For the preflight example, the fields we need are
EstimateQuantity/@quantityOrdered,
EstimateQuantity/@numPages, EstimatePart/@numSigs.
• In the Object Model Browser we find that the calculated
field totalPages is = @numPages * @numSigs so that
is what we will use.
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3. Determine the data type of the
result field.
• Go to the Object Model Browser, select the
target object, click on the Fields tab and find the
Type of the field for your result.
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3. Determine the data type of the
result field.
• Example:
EstimatePrepressOp object; quantity field has a Type
of Integer
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4. Determine how you will cost your
operation based on the data type.
• If the field is an integer, as quantity normally is,
then you need to decide how to define your
cost.
• In a Prepress Operation size you define hours
per unit. Since XPath will return integer units, to
get decimal time, times should be entered as
0.01 hour per unit.
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4. Determine how you will cost your
operation based on the data type.
• Example:
Preflight operation size 99 x 99; Qty Up To 99,999,999;
Hours 0.01. XPath will return an integer value for
units of hundredths of an hour.
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5. Find your fields relative to the
current object.
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5. Find your fields relative to the
current object
• All field references in
XPath are relative to the
object of the result field.
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5. Find your fields relative to the
current object.
• Version 17 Cost Based Estimating Objects
Company
|
Estimate
|
EstimatePart
|
EstimateQuantity
|
| --------------- | ---------------- | ------------------ | ------------------ | -------------- | -------------- |
EstimatePrepressOp - EstimatePress - EstimateFinishingOp - EstimateOutsidePurch - EstimatePaper - EstimateInk - EstimateActivity
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5. Find your fields relative to the
current object.
• We refer to these relationships as:
EstimatePart is a child of Estimate

Estimate
|
EstimatePart


Estimate is the parent of EstimatePart
EstimatePress is a sibling of EstimatePaper
EstimatePress - EstimatePaper
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5. Find your fields relative to the
current object.
• The notation for these is:
../ moves up a generation
../<object name> moves to a sibling
<object name>[condition]/<object>
moves down a generation.
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5. Find your fields relative to the
current object.
• Examples:
If starting location is EstimatePrepressOp,
parent is EstimateQuantity which is referred
to as ../
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5. Find your fields relative to the
current object.
• Examples:
If starting location is EstimatePrepressOp,
sizeDenominator (a field in company) is
../../../../@sizeDenominator
The series of ../ refer, in sequence, to
EstimateQuantity, then EstimatePart, then
Estimate, then Company
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5. Find your fields relative to the
current object.
• Examples:
The [condition] is a way to select a field of a
certain value and find data for that record.
../EstimatePress[@pressIndicator=0]/@runSizeWidth
refers to the sibling object EstimatePress with
a specific record where pressIndicator = 0
(primary press) and gets the runSizeWidth.
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5. Find your fields relative to the
current object.
• Examples:
To use this runSizeWidth, because we store
sizes as integers, you need to divide the
value by the system's size denominator so
the expression would be:
(../EstimatePress[@pressIndicator=0]/@runSizeWidth
div ../../../../@sizeDenominator )
• 38” would be stored as 608 if your sizeDenominator is 16.
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5. Find your fields relative to the
current object.
• Examples:
To get a value from an object outside of the tree shown
above you use a notation like this:
(../EstimatePress[@pressIndicator=0]/press/
@gripperAllowance
This would go to the sibling object, EstimatePress and
select the primary press record, find the press on
that record and return the gripper size.
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5. Find your fields relative to the
current object.
• Examples:
To get a value from an object outside of the tree by
using a direct pointer, use syntax like this:
/InventoryItem[@id='123Test']/@unitPrice
If the object is a singleton (single record object like
many setup objects), then the record selection is not
necessary:
/EstimateSetup/@paperRoundingMode
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6. Write your expression in
simple terms.
• Formula from Step 1 = .25 + (number of pages / 600)
• (¼ hour + ( sum(numPages for all parts) / 600)) * 100
• Remember, units are integers so to get 1/100 of
an hour we must multiply by 100 to get units of
.01 hours. 67 units times .01 hours = .67 hours
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7. Write your expression in XPath.
• (.25 + (sum(../../../EstimatePart/@totalPages)
div 600)) * 100
• Note:
To sum a value you must go to the parent and then
sum the children. Here we go up to the Estimate and
then refer to the EstimateParts. This will give us the
total number of pages in all parts of the Estimate.
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8. Test your expression.
• Go to a sample estimate and manually
calculate the result you want the system to
return.
• In our example, we have a large perfect bound
book of 1,566 pages.
• 1566 @ 600/hour = 2.61 hours + .25 = 2.86
• 2.86 hours * 100 = 286 units
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8. Test your expression.
• Go to a sample estimate and get the object
number as a data starting point.
• Example:
Go to your estimate detail Prepress tab and hover over
a prepress operation drilldown icon. At the bottom of
the browser window will appear a URL like:
http://epace.samplecompany.com/estimating/object/
EstimatePrepressOp/detail/5987
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8. Test your expression.
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8. Test your expression.
• Go to Administration -> System Tools -> XPath
Evaluator.
• In Object Type enter the result's object.
• The primary key is the number at the end of the
URL.
• The data type is from step 3.
• The Expression is the one you have written.
• Hit the Evaluate button and the Result should
produce the value you expect.
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8. Test your expression.
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9. Enter your expression into ePace.
• Go to Administration -> System Setup ->
Estimating -> Misc Setup -> Estimate
Expression Setup.
• Add New Record.
• Enter a name, calculation type and copy your
expression into the appropriate area,
Expression Prepress or Expression Finishing.
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9. Enter your expression into ePace.
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10. Use your expression.
• Go to either a Prepress Workflow or a Finishing
Operation.
• In the Quantity Calc Method select XPath
Expression
• Choose your new expression in the Estimate
Expression field
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10. Use your expression.
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11. Syntax
• ePace uses XPath 1.1 with custom
extensions. If you get an XPath
book, it may have version 2.0
expressions which will not be
understood by ePace.
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11. Syntax
•
•
Any time an expression uses more than one operator, it is necessary to
know what precedence is used. For XPath, this is (highest to lowest):
( ) 'grouping'
[ ] 'filter'
'unary minus'
* div mod 'multiplication division modulus'
+ - 'addition subtraction'
= != < <= > >= 'relational (comparison)'
| 'union'
not 'negation'
and 'conjunction'
or 'disjunction'
Operators at the same precedence level are always evaluated left-to-right.
Parentheses can be used to force the expression to evaluate in a different
order than the default.
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11. Syntax
• Here are the some of the syntax statements that are
currently available:
Comparison operators:
= 'equal to'
!= 'not equal to'
> 'greater than'
>= 'greater than or equal to'
< 'less than'
<= 'less than or equal to'
Contains 'list of values contains test value'
not 'reverses the true/false value of its argument'
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11. Syntax
• Here are the some of the syntax statements
that are currently available:
Conditional Statement:
iif(<value> condition <value>, <result>, <else result>)
this may be nested
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11. Syntax
• Here are the some of the syntax statements
that are currently available:
Arithmetic Statements:
+ 'plus'
- 'minus'
* 'multiply by'
div 'divide by'
mod 'modulus'
null-to-zero 'if @addHours returns [null],
null-to-zero(@addHours) returns 0'
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11. Syntax
• Here are the some of the syntax statements that are
currently available:
Summary Statements:
sum(<value list>)
floor(<value>) result is rounded down toward negative infinity
(negative numbers increase in absolute value)
ceiling(<value>) result is rounded up toward positive infinity
round(<value>) result is rounded. < .5 rounds down
>= .5 rounds up
count(<value>) result is number of records
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11. Syntax
• Here are the some of the syntax statements that are
currently available:
String:
number(<string value>) 'result is a number. Use to convert
string values before math'
contains(string_1, string_2) 'returns true if string_1 contains
string_2'
concat(<string_1>, <string_2>, <string_3>)
'concatenates strings'
starts-with(<string_1>,<string_2>) 'returns true if string_1 starts
with string_2, case sensitive'
string(<value>) 'returns value as string, used to return a
number as a string'
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11. Syntax
• Here are the some of the syntax statements that are
currently available:
String:
string-length(<string>) 'returns number of characters in the
string'
substring(<string>,offset,length) 'returns a substring of <length>
characters starting at <offset> '
substring-after(<string_1>,<string_2>) 'returns the part of
string_1 that follows the 1st occurance of string_2 '
substring-before(<string_1>,<string_2>) 'like substring-after but
returns the part before'
current-date() 'returns the current date and can be used as a
comparison in a iif statement'
current-user() 'returns the current user'
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11. Syntax
• Here are the some of the syntax statements that are currently
available:
Notes:
There is no min or max function that will compare different fields so
use this format:
To return minimum value of x or y use iif (x < y,x,y)
The min and max functions in XPath only return the minimum or
maximum value within a field.
There is no case statement so use nested iif statements.
There is no variable declaration.
All statements must be included in a single statement. You cannot
return multiple values.
The first expression that returns a true in a nested iif statement returns
the value and ends the iif.
It is like writing: if x=y then x end if, if y=z then z end if
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12. Examples
• For a simple price list:
1-10 @ 1.75
11-25 @ 1.50
26 and over @ 1.25
((iif (../@quantityOrdered <= 10, (../@quantityOrdered * 1.75,
iif (../@quantityOrdered >= 11 and ../@quantityOrdered <= 25,
(../@quantityOrdered * 1.50, (../@quantityOrdered * 1.25))))
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12. Examples
• Final Size in 8.5 x 11 equivalents
((../../@finalSizeHeight div (../../../../@sizeDenominator))
* (../../@finalSizeWidth div (../../../../@sizeDenominator))
* 93.5)
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12. Examples
• Banner Hemming - result is final size
perimeter feet
(((../../@finalSizeHeight div
(../../../../@sizeDenominator * 12)) +
(../../@finalSizeWidth div
(../../../../@sizeDenominator * 12))) * 2 *
../@quantityOrdered
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12. Examples
• Grommets - for each part, put a grommet along
each side. Max span = 4 feet, minimum 4 per
piece (each corner)
../@quantityOrdered * (ceiling((../../@finalSizeHeight
div (../../../../@sizeDenominator * 12)) div 4 ) * 2 +
ceiling((../../@finalSizeWidth div
(../../../../@sizeDenominator * 12)) div 4 ) * 2)
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12. Examples
• Laminating - 28" wide - run inches. If the sheet
width is over 28" it has to run short edge into the
laminator, if under 28" then long edge.
(iif((../EstimatePress[@pressIndicator=0]/@runSizeWidth
div (../../../../@sizeDenominator)>28,
((../EstimatePress[@pressIndicator=0]/@runSizeWidth
div (../../../../@sizeDenominator)),
((../EstimatePress[@pressIndicator=0]/@runSizeHeight
div (../../../../@sizeDenominator))
)) * ../@sheetsOffPress
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12. Examples
• Laminating - 28" wide - run inches - add 20% if under 7
point or over 16 point or quantity is under 1000. If the
sheet width is over 28" it has to run short edge into the
laminator, if under 28" then long edge.
iif(../EstimatePaper[1]/paperWeight/@caliper < .007,1.2,
iif(../EstimatePaper[1]/paperWeight/@caliper > .016,1.2,
iif(../@sheetsOffPress < 1000,1.2,1))) *
(iif((../EstimatePress[@pressIndicator=0]/@runSizeWidth div
(../../../../@sizeDenominator)>28,
((../EstimatePress[@pressIndicator=0]/@runSizeWidth div
(../../../../@sizeDenominator)),
((../EstimatePress[@pressIndicator=0]/@runSizeHeight div
(../../../../@sizeDenominator))
)) * ../@sheetsOffPress
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12. Examples
• Laminate material per side in MSI
(../EstimatePress[@pressIndicator=0]/@runSizeWidth
div ../../../../@sizeDenominator) *
(../EstimatePress[@pressIndicator=0]/@runSizeHeight
div ../../../../@sizeDenominator)
* ../@sheetsOffPress div 1000
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12. Examples
• To apply a calculation to the first part of an
estimate
iif(../../@id = min(../../../EstimatePart/@id),<value or
expression>,0)
• For the Preflight Operation this would be
iif(../../@id = min(../../../EstimatePart/@id),
(.25 + (sum(../../../EstimatePart/@totalPages) div 600))
* 100,0)
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12. Examples
• To get the total material cost for an Estimate Part, from
a prepressOp or finishingOp for Canadian tax
• This shows 2 conditions,
EstimateActivity.estimateQuantity = (../@id) AND
EstimateActivity.hours = 0
• Return 12% of the total material cost on the part
0.12 * sum(../EstimateActivity[@estimateQuantity=(../@id) and
null-to-zero(@hours) =0]/@cost)
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Thank you for attending
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