Write, Bureaucrats, Administrators
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Calculation field: Difference between revisions
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{{Stamp|2016-12- | {{Stamp|2016-12-10|4.1.0|1.0.7}} | ||
The values in Calculation fields are calculated from the expressions specified by you in Memento Script, defined herein. | The values in Calculation fields are calculated from the expressions specified by you in Memento Script, defined herein. | ||
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| '''switch''' || expression,<br/>value/result pairs,<br/>default result || 1+(2*#pairs)+1 arguments<br/>The final result based on matching the expression against the paired values to identify the paired result (or else the default result) to be used<br/>Example: switch(#{count}, 1, 'One', 2, 'Two', 'Many') | | '''switch''' || expression,<br/>value/result pairs,<br/>default result || 1+(2*#pairs)+1 arguments<br/>The final result based on matching the expression against the paired values to identify the paired result (or else the default result) to be used<br/>Example: switch(#{count}, 1, 'One', 2, 'Two', 'Many') | ||
|} | |} | ||
== Examples == | == Examples == | ||
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#{item@avg.price} | #{item@avg.price} | ||
</source> | </source> | ||
== Accessing values of linked library entries == | |||
Use the following syntax to get access to the values of Link to Entry and other linking fields: | |||
<source lang="java"> | |||
#{link field name.linked field name} | |||
</source> | |||
where '''''link field name''''' is the name of a Link to Entry field, '''''linked field name''''' is the name of a field of a related entry. | |||
You can select a field, including one from a related library, using the '''+Field''' button. | |||
If a link field contains several links, then use an index (starting from zero) to get access to them: | |||
<source lang="java"> | |||
#{link field name@0.linked field name}, #{link field name@1.linked field name}, … | |||
</source> | |||
You can specify one of the supported aggregation functions instead of the index: | |||
<source lang="java"> | |||
#{link field name@sum.linked field name} | |||
</source> | |||
This expression returns the sum of values of field '''linked field name''' for all entries included into '''link field name'''. The functions supported are: '''sum''', '''avg''', '''min''', and '''max'''. | |||
Use the following syntax to get the number of entries in the library referenced by '''link field name''': | |||
<source lang="java"> | |||
#{link field name@size} | |||
</source> | |||
=== Example: Parents and children === | |||
Parents contains fields Name and Age. Children has fields Name and Parents (link to entry (many-to-many)). | |||
Add field "Average parent age" (calculation, real, scale 1) to Children and select the related field from the '''+Field''' list: parents.age. Then insert "@avg", making it: | |||
<source lang="JavaScript">#{parents@avg.age}</source> | |||
=== Example: Orders of products === | |||
Products has fields SKU, Description, and Price. Orders has fields #, Date, Customer (link to entry (one-to-many)), and Products (link to entry (many-to-many)). | |||
Add field "Total" (calculation, real, scale 2) to Orders and select the related field from the '''+Field''' list: products.price. Then insert "@sum", making it: | |||
<source lang="JavaScript">#{products@sum.price}</source> | |||
'''Note:''' This example points out a deficiency in using a many-to-many relationship for orders of products (or of services). One would hope to associate a quantity for each product ordered, but that requirement cannot be met with this 3-library technique. So, in real life, order solutions generally involve 4 libraries: Customers, Products, Orders, and Order Items. The quantity can reside in Order Items. | |||
{{FieldNameHint}} | {{FieldNameHint}} | ||