How Can I Implement Wildcard Searches Securely with Prepared Statements and the 'LIKE' Keyword?

Implementing Wildcard Search with Prepared Statements Using "like" Keyword

Prepared statements offer a secure and efficient way to execute database queries. For implementing search functionality based on a keyword, the "like" keyword can be utilized. To employ "like" with prepared statements, the wildcard component of the keyword must be incorporated into the query.

Suppose we have a query like this:

PreparedStatement pstmt = con.prepareStatement(
      "SELECT * FROM analysis WHERE notes like ?");

To perform a wildcard search, we need to specify the wildcard pattern in the query. This is achieved by inserting the wildcard character ('%') after the keyword value. For instance, if we want to execute a prefix-match search, we can replace the question mark with a parameter such as notes%:

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

Alternatively, we can use a suffix-match by attaching the wildcard to the beginning of the keyword value:

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

For a global match, we can enclose the keyword value with wildcards:

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

It is crucial to note that when using special characters like '%', they can interfere with the prepared statement. To prevent this interference, we can utilize an escape character. For instance, in the above code, we have introduced an escape character ('!') to prevent the wildcard character from being interpreted as a metacharacter:

PreparedStatement pstmt = con.prepareStatement(
        "SELECT * FROM analysis WHERE notes LIKE ? ESCAPE '!'");

This ensures that the wildcard character is treated as a literal character rather than a metacharacter.

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