IEnumerable vs. IQueryable in C#

Automated excerpt

Expression Trees: The Actual Mechanical Difference → compiles the lambda to a DELEGATE → filters objects ALREADY IN MEMORY, in . NET → only the matching ROWS are ever transferred back into . NET memory 1. Expression Trees: The Actual Mechanical Difference // Compiled to: a real, callable block of IL/machine code. The Classic Bug: Un-Translatable Expressions Section 6 established that translation is real, mechanical work a provider does by walking the expression tree — and that work is fundamentally limited to expression shapes the provider was written to recognize.

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