<?xml version="1.0" encoding="utf-8" ?> <!DOCTYPE chapter SYSTEM "chapter.dtd"> <chapter> <header> <copyright> <year>2002</year><year>2013</year> <holder>Ericsson AB. All Rights Reserved.</holder> </copyright> <legalnotice> The contents of this file are subject to the Erlang Public License, Version 1.1, (the "License"); you may not use this file except in compliance with the License. You should have received a copy of the Erlang Public License along with this software. If not, it can be retrieved online at http://www.erlang.org/. Software distributed under the License is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the specific language governing rights and limitations under the License. </legalnotice> <title>Getting started</title> <prepared>Ingela Anderton Andin</prepared> <responsible></responsible> <docno></docno> <approved></approved> <checked></checked> <date></date> <rev></rev> <file>getting_started.xml</file> </header> <section> <title>Setting things up </title> <p>As the Erlang ODBC application is dependent on third party products there are a few administrative things that needs to be done before you can get things up and running.</p> <p></p> <list type="bulleted"> <item>The first thing you need to do, is to make sure you have an ODBC driver installed for the database that you want to access. Both the client machine where you plan to run your erlang node and the server machine running the database needs the the ODBC driver. (In some cases the client and the server may be the same machine).</item> <item>Secondly you might need to set environment variables and paths to appropriate values. This may differ a lot between different os's, databases and ODBC drivers. This is a configuration problem related to the third party product and hence we can not give you a standard solution in this guide.</item> <item>The Erlang ODBC application consists of both <c>Erlang</c> and <c>C</c> code. The <c>C</c> code is delivered as a precompiled executable for windows, solaris and linux (SLES10) in the commercial build. In the open source distribution it is built the same way as all other application using configure and make. You may want to provide the the path to your ODBC libraries using --with-odbc=PATH. </item> </list> <note> <p>The Erlang ODBC application should run on all Unix dialects including Linux, Windows 2000, Windows XP and NT. But currently it is only tested for Solaris, Windows 2000, Windows XP and NT.</p> </note> </section> <section> <title>Using the Erlang API</title> <p>The following dialog within the Erlang shell illustrates the functionality of the Erlang ODBC interface. The table used in the example does not have any relevance to anything that exist in reality, it is just a simple example. The example was created using <c>sqlserver 7.0 with servicepack 1</c> as database and the ODBC driver for <c>sqlserver</c> with version <c>2000.80.194.00</c>.</p> <code type="none"> 1 > odbc:start(). ok </code> <p>Connect to the database </p> <code type="none"><![CDATA[ 2 > {ok, Ref} = odbc:connect("DSN=sql-server;UID=aladdin;PWD=sesame", []). {ok,<0.342.0>} ]]></code> <p>Create a table </p> <code type="none"> 3 > odbc:sql_query(Ref, "CREATE TABLE EMPLOYEE (NR integer, FIRSTNAME char varying(20), LASTNAME char varying(20), GENDER char(1), PRIMARY KEY(NR))"). {updated,undefined} </code> <p>Insert some data </p> <code type="none"> 4 > odbc:sql_query(Ref, "INSERT INTO EMPLOYEE VALUES(1, 'Jane', 'Doe', 'F')"). {updated,1} </code> <p>Check what data types the database assigned for the columns. Hopefully this is not a surprise, some times it can be! These are the data types that you should use if you want to do a parameterized query.</p> <code type="none"> 5 > odbc:describe_table(Ref, "EMPLOYEE"). {ok, [{"NR", sql_integer}, {"FIRSTNAME", {sql_varchar, 20}}, {"LASTNAME", {sql_varchar, 20}} {"GENDER", {sql_char, 1}}]} </code> <p> <marker id="param_query"></marker> Use a parameterized query to insert many rows in one go. </p> <code type="none"> 6 > odbc:param_query(Ref,"INSERT INTO EMPLOYEE (NR, FIRSTNAME, " "LASTNAME, GENDER) VALUES(?, ?, ?, ?)", [{sql_integer,[2,3,4,5,6,7,8]}, {{sql_varchar, 20}, ["John", "Monica", "Ross", "Rachel", "Piper", "Prue", "Louise"]}, {{sql_varchar, 20}, ["Doe","Geller","Geller", "Green", "Halliwell", "Halliwell", "Lane"]}, {{sql_char, 1}, ["M","F","M","F","F","F","F"]}]). {updated, 7} </code> <p>Fetch all data in the table employee </p> <code type="none"> 7> odbc:sql_query(Ref, "SELECT * FROM EMPLOYEE"). {selected,["NR","FIRSTNAME","LASTNAME","GENDER"], [{1,"Jane","Doe","F"}, {2,"John","Doe","M"}, {3,"Monica","Geller","F"}, {4,"Ross","Geller","M"}, {5,"Rachel","Green","F"}, {6,"Piper","Halliwell","F"}, {7,"Prue","Halliwell","F"}, {8,"Louise","Lane","F"}]]} </code> <p>Associate a result set containing the whole table <c>EMPLOYEE</c> to the connection. The number of rows in the result set is returned.</p> <code type="none"> 8 > odbc:select_count(Ref, "SELECT * FROM EMPLOYEE"). {ok,8} </code> <p>You can always traverse the result set sequential by using next</p> <code type="none"> 9 > odbc:next(Ref). {selected,["NR","FIRSTNAME","LASTNAME","GENDER"],[{1,"Jane","Doe","F"}]} </code> <code type="none"> 10 > odbc:next(Ref). {selected,["NR","FIRSTNAME","LASTNAME","GENDER"],[{2,"John","Doe","M"}]} </code> <p>If your driver supports scrollable cursors you have a little more freedom, and can do things like this. </p> <code type="none"> 11 > odbc:last(Ref). {selected,["NR","FIRSTNAME","LASTNAME","GENDER"],[{8,"Louise","Lane","F"}]} </code> <code type="none"> 12 > odbc:prev(Ref). {selected,["NR","FIRSTNAME","LASTNAME","GENDER"],[{7,"Prue","Halliwell","F"}]} </code> <code type="none"> 13 > odbc:first(Ref). {selected,["NR","FIRSTNAME","LASTNAME","GENDER"],[{1,"Jane","Doe","F"}]} </code> <code type="none"> 14 > odbc:next(Ref). {selected,["NR","FIRSTNAME","LASTNAME","GENDER"],[{2,"John","Doe","M"}]} </code> <p>Fetch the fields <c>FIRSTNAME </c> and <c>NR </c> for all female employees</p> <code type="none"> 15 > odbc:sql_query(Ref, "SELECT FIRSTNAME, NR FROM EMPLOYEE WHERE GENDER = 'F'"). {selected,["FIRSTNAME","NR"], [{"Jane",1}, {"Monica",3}, {"Rachel",5}, {"Piper",6}, {"Prue",7}, {"Louise",8}]} </code> <p>Fetch the fields <c>FIRSTNAME </c> and <c>NR </c> for all female employees and sort them on the field <c>FIRSTNAME </c>. </p> <code type="none"> 16 > odbc:sql_query(Ref, "SELECT FIRSTNAME, NR FROM EMPLOYEE WHERE GENDER = 'F' ORDER BY FIRSTNAME"). {selected,["FIRSTNAME","NR"], [{"Jane",1}, {"Louise",8}, {"Monica",3}, {"Piper",6}, {"Prue",7}, {"Rachel",5}]} </code> <p>Associate a result set that contains the fields <c>FIRSTNAME</c> and <c>NR </c> for all female employees to the connection. The number of rows in the result set is returned.</p> <code type="none"> 17 > odbc:select_count(Ref, "SELECT FIRSTNAME, NR FROM EMPLOYEE WHERE GENDER = 'F'"). {ok,6} </code> <p>A few more ways of retrieving parts of the result set when the driver supports scrollable cursors. Note that next will work even without support for scrollable cursors. </p> <code type="none"> 18 > odbc:select(Ref, {relative, 2}, 3). {selected,["FIRSTNAME","NR"],[{"Monica",3},{"Rachel",5},{"Piper",6}]} </code> <code type="none"> 19 > odbc:select(Ref, next, 2). {selected,["FIRSTNAME","NR"],[{"Prue",7},{"Louise",8}]} </code> <code type="none"> 20 > odbc:select(Ref, {absolute, 1}, 2). {selected,["FIRSTNAME","NR"],[{"Jane",1},{"Monica",3}]} </code> <code type="none"> 21 > odbc:select(Ref, next, 2). {selected,["FIRSTNAME","NR"],[{"Rachel",5},{"Piper",6}]} </code> <code type="none"> 22 > odbc:select(Ref, {absolute, 1}, 4). {selected,["FIRSTNAME","NR"], [{"Jane",1},{"Monica",3},{"Rachel",5},{"Piper",6}]} </code> <p>Select, using a parameterized query. </p> <code type="none"> 23 > odbc:param_query(Ref, "SELECT * FROM EMPLOYEE WHERE GENDER=?", [{{sql_char, 1}, ["M"]}]). {selected,["NR","FIRSTNAME","LASTNAME","GENDER"], [{2,"John", "Doe", "M"},{4,"Ross","Geller","M"}]} </code> <p>Delete the table <c>EMPLOYEE</c>.</p> <code type="none"> 24 > odbc:sql_query(Ref, "DROP TABLE EMPLOYEE"). {updated,undefined} </code> <p>Shut down the connection. </p> <code type="none"> 25 > odbc:disconnect(Ref). ok </code> <p>Shut down the application. </p> <code type="none"> 26 > odbc:stop(). =INFO REPORT==== 7-Jan-2004::17:00:59 === application: odbc exited: stopped type: temporary ok </code> </section> </chapter>