ODBC access with connection pool.

General.

odbc_pool is an Erlang application for querying ODBC database.
odbc_pool uses pre-fetched pool of connections. 
odbc_pool tries to maintain a given number of connections at all times. 
If any of connections in the pool is dropped for any reason, 
the odbc_pool makes periodical reconnection attempts.

To configure odbc_pool, either change environment parameters in odbc_pool.app file,
or specify environment attributes in command line when starting erlang, for example:

erl -odbc_pool pool_size 20

will set up pool size to 20.

Available configuration parameters (see {env, ..} tuple in odbc_pool.app):

pool_size - the size of connections in the pool;
retry_interval - interval (in ms) between attemps to reconnect in case any connection in the pool is lost;
odbc_options - corresponds to odbc options used by odbc:connect/2;
connection_string - ODBC connection string.

Using odbc_pool.

Start erlang shell:

deploy@xmpp2 ~/etc_odbc/odbc_pool $ erl -pa ebin

Start odbc_pool application:

1> application:start(odbc_pool).
ok

Run query:

2> odbc_pool:sql_query("EXEC marketing.MetaTags_SelectAll").
{selected,["Page","KeyWords","Description"],
          [{"/aboutus.aspx",
            "About WebCabby,Who we are, Mission Statement, Get to know us, About Us",
            "Get to know WebCabby. What we are about and our dedication to customer service."},
           {"/aboutus.aspx/",
            "WebCabby,Cab, Taxi, taxicab,order cab online, airport, Transportation, san francisco, paratransit, restaurant, club, bar, tourism",
            "WebCabby is an online taxicab ordering system"},
           {"/aboutus.aspx/Common/CSS/CabbyStyle.css",
            "WebCabby,Cab, Taxi, taxicab,order cab online, airport, Transportation, san francisco, paratransit, restaurant, club, bar, tourism",
            "WebCabby is an online taxicab ordering system"},
           {"/aboutus.aspx/Common/CSS/Nav.css",
            "WebCabby,Cab, Taxi, taxicab,order cab online, airport, Transportation, san francisco, paratransit, restaurant, club, bar, tourism",
            "WebCabby is an online taxicab ordering system"},
           {"/aboutus.aspx/images/BottomBodyW.gif",
            "WebCabby,Cab, Taxi, taxicab,order cab online, airport, Transportation, san francisco, paratransit, restaurant, club, bar, tourism",
            "WebCabby is an online taxicab ordering system"},
           {"/aboutus.aspx/images/Poweredby.png",
            "WebCabby,Cab, Taxi, taxicab,order cab online, airport, Transportation, san francisco, paratransit, restaurant, club, bar, tourism",
            "WebCabby is an online taxicab ordering system"},
           {"/aboutus.aspx/images/TopBody.gif",
            "WebCabby,Cab, Taxi, taxicab,order cab online, airport, Transportation, san francisco, paratransit, restaurant, club, bar, tourism",
            "WebCabby is an online taxicab ordering system"},
           {"/administration/4gotpw.aspx",
            "WebCabby,Cab, Taxi, taxicab,order cab online, airport, Transportation, san francisco, paratransit, restaurant, club, bar, tourism",
            "WebCabby is an online taxicab ordering system"},
           {"/Administration/default.aspx",
            "WebCabby,Cab, Taxi, taxicab,order cab online, airport, Transportation, san francisco, paratransit, restaurant, club, bar, tourism",
            "WebCabby is an online taxicab ordering system"},
           {"/Administration/Dispatchers/Default.aspx",
            "WebCabby,Cab, Taxi, taxicab,order cab online, airport, Transportation, san francisco, paratransit, restaurant, club, bar, tourism",
            "WebCabby is an online taxicab ordering system"},
           {"/administration/Dispatchers/LastLoginTimes.aspx",
            "WebCabby,Cab, Taxi, taxicab,order cab online, airport, Transportation, san francisco, paratransit, restaurant, club, bar, tourism",
            "WebCabby is an online taxicab ordering system"},
           {"/administration/ErrorLogs.aspx",
            "WebCabby,Cab, Taxi, taxicab,order cab online, airport, Transportation, san francisco, paratransit, restaurant, club, bar, tourism",
            "WebCabby is an online taxicab ordering system"},
           {"/Administration/Orders/StatusCheck.aspx",
            "WebCabby,Cab, Taxi, taxicab,order cab online, airport, Transportation, san francisco, paratransit, restaurant, club, bar, tourism",
            "WebCabby is an online taxicab ordering system"},
           {"/Administration/Security/Roles.aspx",
            "WebCabby,Cab, Taxi, taxicab,order cab online, airport, Transportation, san francisco, paratransit, restaurant, club, bar, tourism",
            "WebCabby is an online taxicab ordering system"},
           {"/Affiliate/Components.aspx",
            "WebCabby,Cab, Taxi, taxicab,order cab online, airport, Transportation, san francisco, paratransit, restaurant, club, bar, tourism",
            "WebCabby is an online taxicab ordering system"},
           {"/Affiliate/Embeded/QuickCabbyWidget.aspx",
            "WebCabby,Cab, Taxi, taxicab,order cab online, airport, Transportation, san francisco, paratransit, restaurant, club, bar, tourism",
            "WebCabby is an online taxicab ordering system"},
           {"/Affiliate/Embeded/Step2.aspx",
            "WebCabby,Cab, Taxi, taxicab,order cab online, airport, Transportation, san francisco, paratransit, restaurant, club, bar, tourism",
            "WebCabby is an online taxicab ordering system"},
           {"/Affiliate/Embeded/Step3.aspx",
            "WebCabby,Cab, Taxi, taxicab,order cab online, airport, Transportation, san francisco, paratransit, restaurant, club, bar, tourism",
            "WebCabby is an online taxicab ordering system"},
           {"/common/TrackOrder.aspx",
            "WebCabby,Cab, Taxi, taxicab,order cab online, airport, Transportation, san francisco, paratransit, restaurant, club, bar, tourism",
            "WebCabby is an online taxicab ordering system"},
           {"/contactus.aspx",
            "WebCabby,Cab, Taxi, taxicab,order cab online, Contact us, Contact Information",
            "Contact WebCabby with any comments or suggestions. We will respond to your email as soon as posible"},
           {"/DOWNLOADS.ASPX",
            "WebCabby,Cab, Taxi, taxicab,order cab online, airport, Transportation, san francisco, paratransit, restaurant, club, bar, tourism",
            "WebCabby is an online taxicab ordering system"},
           {"/Error.aspx",
            "WebCabby,Cab, Taxi, taxicab,order cab online, airport, Transportation, san francisco, paratransit, restaurant, club, bar, tourism",
            "WebCabby is an online taxicab ordering system"},
           {"/home.aspx",
            "WebCabby,Cab, Taxi, taxicab,order cab online, airport, Transportation, San Francisco, para transit",
            [...]},
           {"/Home.aspx/",[...],...},
           {[...],...},
           {...}|...]}

Note: the odbc_pool:sql_query/1 produces output that corresponds to odbc:sql_query/2.