Coldfusion – variable field name when looping through database query results

by

Don’t use Evaluate() for things like that! It’s slow and should be avoided.

<cfloop index="i" from="1" to="4">
  <cfset foo = query["foo" & i][query.CurrentRow]>
</cfloop>

Or, if you like:

<cfloop index="i" from="1" to="4">
  <cfset foo = query["foo#i#"][query.CurrentRow]>
</cfloop>

Evaluate() is for evaluating bits of code. Don’t use it for things that can be solved more elegantly in language-integrated, more appropriate ways.

EDIT:

When accessing Query objects with the “angle bracket”-syntax, you must append the (1-based) row number index (query["foo#i#"][RowNum]). When using the traditional “dot”-syntax (query.foo1), the current row is implicit.

To access the current row explicitly, use the QueryObject.CurrentRow property. But it could be any positive integer up to QueryObject.RecordCount. A range check is advised for anything other than CurrentRow.

This opens an interesting field: You can start to use query objects with “random access”. Previously (before CFMX) all you could do was iterate them from start to end, pulling out the things that you look for. Now it’s like a nested struct/array data structure that you can use in different ways.

More Related Contents:

  1. SQL NVARCHAR and VARCHAR Limits
  2. How do you use script variables in psql?
  3. How do I use variables in Oracle SQL Developer?
  4. How to declare variable and use it in the same Oracle SQL script?
  5. Declare variable in SQLite and use it
  6. ColdFusion adding extra quotes when constructing database queries in strings
  7. How to return the output of stored procedure into a variable in sql server
  8. Varchar variable is not working in WHERE clause
  9. Pass string variable in R script to use it in SQL statement
  10. How to compare dates in SQL Server
  11. Store and reuse value returned by INSERT … RETURNING
  12. SQL Access ” Count “? [closed]
  13. What are the options for storing hierarchical data in a relational database?
  14. Splitting string into multiple rows in Oracle
  15. SQL JOIN vs IN performance?
  16. Microsoft Jet wildcards: asterisk or percentage sign?
  17. A beginner’s guide to SQL database design [closed]
  18. Pivoting data in MS Access
  19. SQL (ORACLE): ORDER BY and LIMIT [duplicate]
  20. Combining the results of two SQL queries as separate columns
  21. How do I delete a fixed number of rows with sorting in PostgreSQL?
  22. How to check if a string is a uniqueidentifier?
  23. Why is SQL server throwing this error: Cannot insert the value NULL into column ‘id’?
  24. Convert INT to DATETIME (SQL)
  25. Get unique values using STRING_AGG in SQL Server
  26. How to create Temp table with SELECT * INTO tempTable FROM CTE Query
  27. Counting the number of occurrences of a substring within a string in PostgreSQL
  28. How to check if a column exists before adding it to an existing table in PL/SQL?
  29. SQL Server equivalent to MySQL’s EXPLAIN
  30. Entity Framework Skip/Take is very slow when number to skip is big

Leave a Comment