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This example is a simple SQL query using a fixed SQL string.
:- use_module(library(odbc)). example_select :- odbc_env_open(EnvHandle), odbc_db_open('MyDatabase', EnvHandle, ConnectionHandle), odbc_query_open(ConnectionHandle, StatementHandle), odbc_query_execute_sql(StatementHandle, 'SELECT cookie,soft FROM bakery order by soft', ResultSet), show_result(ResultSet), odbc_query_close(ResultSet), odbc_db_close(ConnectionHandle), odbc_env_close(EnvHandle). show_result(ResultSet) :- odbc_sql_fetch(ResultSet, Row), show_result1(Row, ResultSet). show_result1([], _ResultSet) :- !. show_result1(Row, ResultSet) :- format('~w~n', [Row]), flush_output, odbc_sql_fetch(ResultSet, Row1), show_result1(Row1, ResultSet).
As always, you begin by opening an environment.
You then connect to the database with odbc_db_open/3
.
The first argument is the identifier for the database in the DBMS.
In this scenario, connecting to the database does not require a
username and a password.
The output from odbc_db_open/3
is an opaque handle on the
database.
First, odbc_query_open/2
is used to create an SQL query, which is
straightforward.
Then, odbc_query_execute_sql/3
is used to execute the SQL
query. By executing an SQL query a result set is created.
Each consecutive call of odbc_sql_fetch/2
will retrieve one
row from the result set.