xpath for cost based estimating

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XPath for Cost Based Estimating

Fusion 08Duncan Seibert


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.


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.


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.



• 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.



• 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.



• There are two way to determine the names of the fields to use.



• 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.



• 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



• 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.



• 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.



• Example: EstimatePrepressOp object; quantity field has a Type

of Integer



• 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.



• 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.


5. Find your fields relative to the current object

• All field references in XPath are relative to the object of the result field.


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



• 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



• The notation for these is:

../ moves up a generation

../<object name> moves to a sibling

<object name>[condition]/<object> moves down a generation.



• Examples:

If starting location is EstimatePrepressOp, parent is EstimateQuantity which is referred to as ../



• 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



• 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.



• 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.



• 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.



• 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


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


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.



• 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



• 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



• 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.



• 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.



• 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


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.


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.


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'


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


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'


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


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'


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'


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


12. Examples

• For a simple price list: 1-10 @ 1.7511-25 @ 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))))


12. Examples

• Final Size in 8.5 x 11 equivalents((../../@finalSizeHeight div (../../../../@sizeDenominator))

* (../../@finalSizeWidth div (../../../../@sizeDenominator))

* 93.5)


12. Examples

• Banner Hemming - result is final size perimeter feet(((../../@finalSizeHeight div

(../../../../@sizeDenominator * 12)) + (../../@finalSizeWidth div

(../../../../@sizeDenominator * 12))) * 2 * ../@quantityOrdered


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)


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


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


12. Examples

• Laminate material per side in MSI(../EstimatePress[@pressIndicator=0]/@runSizeWidth

div ../../../../@sizeDenominator) *

(../EstimatePress[@pressIndicator=0]/@runSizeHeight div ../../../../@sizeDenominator)

* ../@sheetsOffPress div 1000


12. Examples

• To apply a calculation to the first part of an estimateiif(../../@id = min(../../../EstimatePart/@id),<value or

expression>,0)

• For the Preflight Operation this would beiif(../../@id = min(../../../EstimatePart/@id),

(.25 + (sum(../../../EstimatePart/@totalPages) div 600)) * 100,0)


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 part0.12 * sum(../EstimateActivity[@estimateQuantity=(../@id) and

null-to-zero(@hours) =0]/@cost)


Thank you for attending

xpath for cost based estimating

Documents

field names

xpath expression

data type

expression language

fields relative

fields tab

calculated fields

result field