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SQLite Parameters - Not allowing tablename as parameter

I'm developing an application in AIR via Flex, but I'm not seeing where I'm going wrong with SQLite (I'm used to MySQL). Parameters work, but only in certain instances. Is this part of the built-in sanitation system against sql injection? Thanks for any help!

Works:

sqlite

"INSERT :Fields FROM Category", where the parameter is :Fields = "*"

as3

var statement:SQLStatement = new SQLStatement();
statement.connection = connection;
statement.text = "INSERT :Fields FROM Category";
statement.parameters[":Fields"] = "*";
statement.execute;

Doesn't Work (SQL syntax error at ":Table"):

sqlite

"INSERT :Fields FROM :Table", where the parameters are :Fields = "*" and :Table = "Category"

as3

var statement:SQLStatement = new SQLStatement();
statement.connection = connection;
statement.text = "INSERT :Fields FROM :Table";
statement.parameters[":Fields"] = "*";
statement.parameters[":Table"] = "Category";
statement.execute;
like image 827
user117046 Avatar asked Aug 13 '09 20:08

user117046


1 Answers

Generally one cannot use SQL parameters/placeholders for database identifiers (tables, columns, views, schemas, etc.) or database functions (e.g., CURRENT_DATE), but instead only for binding literal values.

With server-side support for parameterized (a.k.a. prepared) statements, the DB engine parses your query once, remembering out the peculiars of any parameters -- their types, max lengths, precisions, etc. -- that you will bind in subsequent executions of the already-parsed query. But the query cannot be properly parsed into its syntactic elements if critical bits, like database objects, are unknown.

So, one generally has to substitute table names oneself, in a stored procedure or in client code which dynamically concats/interpolates/whatevers the SQL statement to be properly executed. In any case, please remember to use your SQL API's function for quoting database identifiers, since the API won't do it for you.

like image 193
pilcrow Avatar answered Oct 10 '22 03:10

pilcrow