How Can I Securely Use the LIKE Wildcard with Prepared Statements?

Prepared Statement with the LIKE Wildcard: A Complete Guide

In the realm of database querying, prepared statements offer a secure and efficient way to execute parameterized queries. When searching for data based on specific keywords or patterns, the LIKE wildcard comes into play.

To use the LIKE wildcard effectively with prepared statements, it's crucial to understand its placement within the code. Contrary to directly adding it to the prepared statement itself (as in pstmt.setString(1, notes "%")), you need to incorporate it into the value itself.

For instance, to perform a prefix match, use the following approach:

notes = notes
    .replace("!", "!!")
    .replace("%", "!%")
    .replace("_", "!_")
    .replace("[", "![");
PreparedStatement pstmt = con.prepareStatement(
        "SELECT * FROM analysis WHERE notes LIKE ? ESCAPE '!'");
pstmt.setString(1, notes + "%");

For a suffix match, modify it as follows:

pstmt.setString(1, "%" + notes);

And for a global match, use this syntax:

pstmt.setString(1, "%" + notes + "%");

It's important to note that escaping special characters in the string (such as "%" and "_") is essential to prevent SQL injection vulnerabilities. By doing so, you ensure that the LIKE wildcard is interpreted correctly and protects your database from malicious attacks.

With this in-depth demonstration, you can now effectively employ the LIKE wildcard in prepared statements, enabling you to implement robust and secure database searching capabilities in your applications.

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