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Explanatory Question

Understanding .value() vs queryValue() Using a Runnable X++ Class

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Read the answer carefully and go through the related questions on the right side to improve your understanding of this topic.

Answer with Explanation

“Today we are going to analyze a real runnable X++ class and understand an important concept used in almost every Dynamics 365 Finance & Operations project — Query ranges and how values are passed to them.”

“This is not theory. This is exactly how Microsoft writes code in real projects.”

❓ Question 1: What is the purpose of this class?

Code reference

internal final class Ansari_Test_QueryValueVsValue

Answer

This class is created to:

  • Compare two ways of passing values to a query range

  • Test:

    1. .value(_custAccount)

    2. .value(queryValue(_custAccount))

  • Prove that both work, but best practices differ

❓ Question 2: Why is this a runnable class?

Code reference

public static void main(Args _args)

Answer

  • This is the entry point of the class

  • The system calls this method when:

    • A menu item is executed

    • Or the class is run directly

  • This allows us to:

    • Execute queries

    • Print results using info()

❓ Question 3: Why are we declaring these objects?

Code reference

Query query;
QueryBuildDataSource qbds;
QueryRun queryRun;
SalesTable salesTable;

Answer

Object Purpose
Query Holds the query definition
QueryBuildDataSource Defines tables and ranges
QueryRun Executes the query
SalesTable Holds fetched records

“This is the standard structure for executing queries in X++.”

❓ Question 4: Why is CustAccount declared like this?

Code reference

CustAccount custAccount = "US-004";

Answer

  • CustAccount is an EDT (Extended Data Type)

  • It is:

    • A string

    • Controlled

    • Clean

  • This makes it a trusted input

“This is why Microsoft sometimes passes it directly without queryValue().”

❓ Question 5: What does this log message indicate?

Code reference

info("===== Using .value(_custAccount) =====");

Answer

  • Marks Test Case 1

  • Helps us clearly identify:

    • Which query logic is running

    • Which output belongs to which approach

❓ Question 6: What happens in Query 1?

Code reference

qbds.addRange(fieldNum(SalesTable, CustAccount))
 .value(custAccount);

Answer

  • A range is added on SalesTable.CustAccount

  • The value is passed directly

  • Works because:

    • The value is a trusted string

    • Comes from an EDT

“This is why you often see this pattern in OOB classes.”

❓ Question 7: How is the query executed?

Code reference

queryRun = new QueryRun(query);
while (queryRun.next())
{
 salesTable = queryRun.get(tableNum(SalesTable));
}

Answer

  • QueryRun executes the query

  • next() fetches one record at a time

  • get() retrieves the table buffer

❓ Question 8: What does this output prove?

Code reference

info(strFmt("SalesId: %1 | CustAccount: %2",
 salesTable.SalesId,
 salesTable.CustAccount));

Answer

  • Records are fetched correctly

  • Confirms:

    • .value(_custAccount) works

❓ Question 9: Why test the second query?

Code reference

info("===== Using .value(queryValue(_custAccount)) =====");

Answer

  • This marks Test Case 2

  • Demonstrates best practice

❓ Question 10: What does queryValue() actually do?

Code reference

.value(queryValue(custAccount));

Answer

queryValue():

  • Converts the value into a query-safe string

  • Adds:

    • Proper quoting

    • Formatting

    • Escaping

  • Works for:

    • Strings

    • Enums

    • Integers

    • Dates

“This makes the query safer and future-proof.”

❓ Question 11: Why do both queries return the same result?

Answer

Because:

  • The value is a clean string

  • No special characters

  • Both formats are accepted by the query engine

“Working code does not always mean best practice code.”

❓ Question 12: When is .value(_custAccount) acceptable?

Answer

  • When the value:

    • Comes from an EDT

    • Is controlled

    • Is not user-manipulated

  • Common in:

    • OOB classes

    • Dialog-based filters

❓ Question 13: When must queryValue() be used?

Answer

Always use queryValue() when:

  • The field is:

    • Enum

    • Int

    • Date

  • The value comes from:

    • User input

    • Integration

    • External systems

❓ Question 14: What is the final verdict?

Teacher’s Final Statement

“Both approaches work. Microsoft uses .value(value) for trusted string EDTs.
But as developers, we should prefer queryValue() in custom code because it is safer, cleaner, and future-proof.”

⭐ One-Line Interview Answer (Must Remember)

.value(value) is acceptable for trusted string inputs and used in OOB code, while queryValue() is the recommended and safer approach for custom and dynamic scenarios.

🎯 Closing Teaching Tip

“Always ask yourself one question before choosing:
Is this value fully trusted?
If not — use queryValue().”