JDBC in Three-Tier Setups — Driver Types to Use In a three-tier architecture, and assuming the web server and DBMS run on the same machine, which JDBC driver type(s) are generally suitable choices?

Introduction:
Choosing the right JDBC driver in a multi-tier architecture affects portability, performance, and operational simplicity. Pure Java drivers avoid native dependencies and are easier to deploy, especially across clustered or containerized environments.

Given Data / Assumptions:

• The architecture is three-tier (browser, web/app server, database).
• The web server and DBMS may be co-located, but portability is still valuable.
• Type 3 and Type 4 are pure Java and widely recommended.

Concept / Approach:
Type 3 drivers use a middleware server; Type 4 drivers speak the DB wire protocol directly. Both run without native code, which simplifies deployment and scaling. Type 1 (JDBC-ODBC bridge) is obsolete and requires ODBC. Type 2 requires native libraries and complicates deployment and maintenance. Thus, Type 3 and Type 4 are the typical best choices in three-tier setups, regardless of server co-location with the DBMS.

Step-by-Step Solution:
1) Prefer pure Java drivers for portability and ease of deployment.2) Discard Type 1 (legacy/ODBC) and Type 2 (native code).3) Select “Both Type 3 and Type 4.”

Verification / Alternative check:
Modern vendor guidance and practice overwhelmingly favor Type 4 in particular; Type 3 is also acceptable where middleware fits the architecture.

Why Other Options Are Wrong:

• Type 1 only: Obsolete and unsuitable for production.
• Type 2 only: Ties you to native libraries; avoid when possible.
• All types: Overbroad; some types are undesirable.
• Type 1 and Type 4 only: Still includes the deprecated Type 1.

Common Pitfalls:
Underestimating deployment friction from native dependencies in scaled-out environments.

Final Answer:
Both Type 3 and Type 4