Two-tier vs. N-tier

Two-tier approaches, while allowing more rapid development, are inherently less scalable than N-tier solutions (such as Web-based database solutions).[citation needed] In a two-tier solution, there must be one connection to the database for each concurrent user, whereas with N-tier solutions, which incorporate connection-pooling technology, a limited number of database connections - sometimes, just a single connection - are multiplexed among a much larger number of actual concurrent users.

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