1.3 Prepared Statements

(prepared-statement? x) → boolean?

x : any

Returns #t if x represents a MySQL prepared statement, #f otherwise.

(prepare [#:connection con] sql) → prepared-statement?

con : connection? = (current-connection)

sql : string?

Prepares a single, parameterized SQL statement for execution. The SQL statement may use question marks (?) in place of SQL value expressions. Each question mark denotes a parameter that may be supplied at execution time. For example, the following:

      (define stmt (prepare "UPDATE foo_tbl SET name = ? WHERE id = ?"))

... defines stmt as a prepared statement with two parameters.

(prepared-statement-parameter-count stmt)

→ exact-nonnegative-integer?

stmt : prepared-statement?

Returns the number of parameters in the given stmt.

(execute stmt arguments) → query-result?

stmt : prepared-statement?

arguments : (listof any)

Executes a prepared-statement, substituting the provided arguments for the parameters of stmt in positional order. The length of the arguments list must be equal to the number of parameters in stmt, otherwise exn:fail:contract is raised.

Note that not all scheme values are valid as parameter values (e.g., output ports). If such a value is encountered, exn:fail:contract is raised.