In database applications, embedded SQL refers to which of the following?

Introduction / Context:
Many business applications interact with a database through a host programming language such as Java, C, or Python. Embedded SQL is a technique used to integrate SQL commands directly into that host language source code. This question asks you to identify the best description of embedded SQL, which is a fundamental concept in older enterprise systems and remains relevant for understanding how applications communicate with relational databases.

Given Data / Assumptions:

• We assume there is an application written in a host language such as Java or C.
• The application needs to send SQL commands to a relational database.
• We want to know what embedded SQL means in this context.

Concept / Approach:
Embedded SQL means that SQL statements are written directly within the host language code and are processed by a precompiler or special library. For example, a C program might contain EXEC SQL SELECT ...; blocks that are transformed into function calls. This is different from dynamic SQL, where the application builds SQL strings at runtime, and different from code inside triggers or stored procedures, which live inside the database, not in the client application source code.

Step-by-Step Solution:
Step 1: Examine option A, which describes dynamically generated SQL with no predefined statements. This is closer to dynamic SQL, not embedded SQL. Step 2: Examine option B, which limits hard coded SQL to triggers. Triggers are database objects, and their SQL is not what is usually meant by embedded SQL. Step 3: Examine option C, which describes hard coded SQL statements inside a host programming language such as Java or C. This matches the standard definition of embedded SQL. Step 4: Examine option D, which talks about hard coded SQL in stored procedures, which again live inside the database, not in external application code. Step 5: Conclude that option C is the correct definition of embedded SQL.

Verification / Alternative check:
Traditional embedded SQL tools, such as Pro*C for Oracle, allow developers to place EXEC SQL statements directly in C code. A precompiler reads this source, translates the embedded SQL into low level database API calls, and produces pure C code. This workflow is the classic example of embedded SQL and confirms that SQL is embedded in the host language, not the other way around.

Why Other Options Are Wrong:
Option A is wrong because generating SQL on the fly at runtime is usually called dynamic SQL, not embedded SQL. Option B is wrong because triggers are database side objects, and although they contain SQL, their SQL is not considered embedded in a host language. Option D is wrong because stored procedures are also defined on the database server and are not embedded within an external programming language source file.

Common Pitfalls:
A common confusion arises between embedded SQL and dynamic SQL, since both involve applications sending SQL to a database. Embedded SQL relies on static SQL statements known at compile time, while dynamic SQL builds queries at runtime as strings. Another pitfall is forgetting that embedded SQL requires a precompiler or special libraries, while normal runtime APIs like JDBC or ODBC are not usually described as embedded SQL even though they execute SQL statements.

Final Answer:
Embedded SQL refers to placing hard coded SQL statements inside a host programming language such as Java or C, as described in option C.