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PDO Reference

By iwantcoding.com Editorial Team · Reviewed & last updated June 6, 2026 · Part of PHP Tutorial

PDO API reference. PDO is the connection; PDOStatement is the prepared / executed query.

PDO methods

Method	Returns
`__construct($dsn, $u, $p, $opts)`	Connect.
`query($sql, $fetchMode = null)`	One-shot select. Returns PDOStatement.
`exec($sql)`	One-shot non-select. Returns row count.
`prepare($sql, $options = [])`	Returns PDOStatement.
`lastInsertId($name = null)`	Latest auto-id.
`beginTransaction() / commit() / rollBack()`	Transactions.
`inTransaction()`	True if a tx is open.
`getAttribute($attr) / setAttribute($attr, $v)`	Tweak driver options.
`quote($s, $type = PDO::PARAM_STR)`	Escape for SQL — prefer prepared instead.

PDOStatement methods

Method	What it does
`execute($params = [])`	Run with bound params.
`bindValue($n, $v, $type)`	Bind a literal.
`bindParam($n, &$v, $type)`	Bind by reference.
`fetch($mode = null)`	One row.
`fetchAll($mode = null)`	All rows.
`fetchColumn($col = 0)`	One value from one column.
`fetchObject($class = stdClass::class)`	One row as object.
`rowCount()`	Affected/returned row count.
`columnCount()`	Number of columns in result.
`closeCursor()`	Release the cursor for reuse.

Fetch modes

Constant	Rows look like
`PDO::FETCH_ASSOC`	Associative array (most common).
`PDO::FETCH_NUM`	Numeric array.
`PDO::FETCH_BOTH`	Both (default — wasteful).
`PDO::FETCH_OBJ`	stdClass with column-named props.
`PDO::FETCH_CLASS`	Instances of a class you provide.
`PDO::FETCH_KEY_PAIR`	First col → second col as a map.
`PDO::FETCH_COLUMN`	Just one column, as a list.

Error modes

Constant	Behaviour
`PDO::ERRMODE_SILENT`	You must check returns. Avoid.
`PDO::ERRMODE_WARNING`	PHP warning + return false.
`PDO::ERRMODE_EXCEPTION`	Use this. Throws PDOException.

Tip: The connect-time options array is the right place to set ATTR_ERRMODE, ATTR_DEFAULT_FETCH_MODE, and ATTR_EMULATE_PREPARES — done once, applied everywhere.

Lesson at a glance

Your progress through the PHP Tutorial track.

Aspect	Detail
Track	PHP Tutorial
Topic	PDO Reference
Section	PHP References
Position	Lesson 81 of 90
Difficulty	Advanced
Previous	← MySQLi Functions
Next	JSON Reference →

Example

<?php
// PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION
// fetch(PDO::FETCH_ASSOC), fetchAll, fetchColumn
// prepare, execute, bindValue, bindParam, rowCount
// lastInsertId, beginTransaction, commit, rollBack
echo 'PDO is the standard DB abstraction layer.';

Try it Yourself »

Exercise

Fetch one column value.

$stmt-> ()

Test yourself

📚 Study aids for PDO Reference

Reading is only step one. To lock in pdo reference from the PHP Tutorial track, use the interactive tools iwantcoding.com ships with every lesson:

Try it live — open the in-browser PHP Tutorial editor and paste in the example above. No install required.
Drill the terms — flip through the PHP Tutorial flashcards to memorise syntax and keywords.
Prove you know it — take the PHP Tutorial boss quiz for a 10-question randomised test across the whole track.
Keep a reference — bookmark the PHP Tutorial cheatsheet for quick lookups while you code.
Continue the track — the next lesson is JSON Reference.

💡 Editor's tip: Learners who complete the flashcards before the boss quiz score, on average, 22% higher on the first attempt. Reading → drilling → testing → building is the order that sticks.

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