PHP PHP Database Integration & MySQL 2

Question 1

What syntax does PDO use for named placeholders in prepared statements?

Accepted Answer

:name

Answer

PDO named placeholders use a colon prefix (e.g., :username), which are then bound to actual values via bindParam() or bindValue().

Question 2

Which PDO method binds a PHP variable to a named placeholder, passing by reference?

Accepted Answer

bindParam()

Answer

bindParam() binds a PHP variable by reference to a named placeholder, so the value is read at execution time.

Question 3

How should PDO connection errors be caught in PHP?

Accepted Answer

Using try-catch with PDOException

Answer

PDO throws PDOException on connection and query failures when error mode is set to exceptions, which should be caught with try-catch.

Question 4

Which PDO attribute setting enables exceptions to be thrown on database errors?

Accepted Answer

PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION

Answer

Setting PDO::ATTR_ERRMODE to PDO::ERRMODE_EXCEPTION causes PDO to throw PDOException objects on errors.

Question 5

What does PDOStatement::rowCount() return after a SELECT query in most databases?

Accepted Answer

An unpredictable or zero value (behavior varies by driver)

Answer

rowCount() reliably returns affected rows for INSERT/UPDATE/DELETE, but its behavior with SELECT is driver-dependent and often returns 0.

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