Why Can't I Use Prepared Statements for Table Names in SQL?

SQL Prepared Statements and Table Names: A Common Pitfall

Prepared statements are crucial for secure SQL queries, preventing SQL injection vulnerabilities. However, a frequent misconception is that table names can be parameterized within a prepared statement. This is incorrect.

The following example illustrates the problem: Attempting to use a prepared statement to dynamically specify a table name (e.g., query1) using a parameter ([?]) and a variable like reportDate will fail. The error "Parameter 'Pa_RaM000' specified where a table name is required" highlights this limitation.

The Solution: Dynamic Construction Outside the Prepared Statement

The core issue is that SQL parsers treat table names differently from other query parameters. They cannot be dynamically injected via prepared statement placeholders.

The correct approach involves constructing the table name dynamically before the prepared statement is used. This is done by concatenating the variable containing the date portion (e.g., reportDate) with the fixed parts of the table name:

private String query1 = "SELECT plantID, edrman, plant, vaxnode FROM [" + reportDate + ".?]";

Here, reportDate provides the date-specific part of the table name, which is combined with the static portion. The remaining parameters within the SELECT statement can then be safely parameterized within the prepared statement itself.

This method allows for dynamic query generation while maintaining the security advantages of prepared statements for the data values.

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