1.3.3 The SQL statement class

execute

Generic function

Summary

Prepares an SQL statement for execution on the specified connection and then executes the statement.

Signature

execute sql-statement #key connection parameters result-set-policy liaison => result-set

Arguments

sql-statement: An instance of <sql-statement>.
connection: An instance of <connection>.
parameters: An instance of false-or(<sequence>).
result-set-policy: An instance of false-or(<result-set-policy>).
liaison: An instance of false-or(<function>) whose signature is liaison(<record>) => <object>. Default value: default-liaison.

Values

result-set: An instance of false-or(<result-set>).

Library

sql

Module

sql

Description

Prepares the SQL statement represented by sql-statement for execution on the connection, then sends it to the DBMS for execution.

If connection is not supplied, execute uses the connection returned by default-connection instead.

The liaison function is invoked on each record as it is retrieved from the database. If a liaison function is not provided, a default value of default-liaison is used; each result-set class has its own default-liaison.

In the SQL-ODBC library, the database-statement will be an instance of <sql-statement>. If anonymous host variables--that is, question marks (?)--appear in database-statement, pass suitable substitution values in the call to this function.

Example:

This example executes two SQL statements against the database represented by the-connection. The first SQL statement inserts a new book record into the book table. The second SQL statement queries for the list of titles and their ISBN published by Addison Wesley.

with-connection(the-connection)
  let insert-stmt :: <sql-statement> =
  make(<sql-statement>,
    text: "insert into book (title, publisher, isbn) 
               values (?, ?, ?)",
    input-indicator: $null-value);
  execute(insert-stmt,
          parameters: #("Large Databases", "Addison-Wesley",
                        $null-value));

let query-stmt :: <sql-statement> =
  make(<sql-statement>, 
  text: "select title, isbn from book 
             where publisher = ?",
             output-indicator: $null-value);
  execute(query-stmt, parameters: #("Addison-Wesley"));
end with-connection;

=> #(#("An Introduction to Database Systems", "0-201-14201-5"),
     #("Relational Database Writings, 1991-1994", "0-8053-1748-1), #("Large Databases", $null-value))