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: Hi Sven, : mit Hilfe von Embedded SQL kann man von C aus auf DB2-Tabellen zugreifen (SELECT, UPDATE, DELETE, INSERT, etc). : Falls das Anwendungsprogramm auf einer anderen Hardwareplattform läuft als die Datenbank selbst, benötigst Du noch eine passende Middleware, wie z. B. DB2 Connect, die die Verbindung herstellt. : Nachfolgend noch ein kleines Beispielprogrämmchen in C mit SQL. : Viel Glück : Bunbury : : /***** Sample Application program #1 *****/ : /******************************************************************** : * SAMPLE PROGRAM: example1.sqc : * : * PURPOSE: This sample program demonstrates the use of embedded SQL : * in DB2. The program makes use of CURSOR to manage the : * query output. Assuming the following table in our database, : * the program retrieves all video titles. : * : * create table video(video_id int not null, \ : * video_title varchar(30), \ : * director varchar(20), \ : * primary key(video_id)) : * : ********************************************************************/ : #include : /* sqlca: is the sql communications area. All error codes : are returned from db2 in that structure which is filled : each time an interaction with db2 takes place. : ************************************* : * No error : sqlca.sqlcode = 0 * : * SQL warning : sqlca.sqlcode > 0 * : * SQL error : sqlca.sqlcode < 0 * : * not found : sqlca.sqlcode = 100 * : ************************************* : */ : EXEC SQL INCLUDE SQLCA; /* SQL communication area structure */ : EXEC SQL BEGIN DECLARE SECTION; /* declare host variables */ : char db_name[8]; /* database name */ : char video_title[30]; /* title of the video */ : short video_id; /* serial number */ : char director[20]; /* director name */ : EXEC SQL END DECLARE SECTION; : void main() { : strcpy(db_name, "csc2509h"); : /* C variables are preceded by a colon when they are passed to DB2 */ : EXEC SQL CONNECT TO :db_name; : if (sqlca.sqlcode != 0) { : printf("Connect failed!: reason %ld\n", sqlca.sqlcode); : exit(1); : } : /* cursor declaration. Have to declare a cursor each time you : want tuples back from db2 : */ : EXEC SQL DECLARE c1 CURSOR FOR : SELECT video_title : FROM video; : /* you have to open the cursor in order to get tuples back */ : EXEC SQL OPEN c1; : do { : /* fetch tuples from the cursor. This will execute the statement : the cursor implements and will return the results */ : EXEC SQL FETCH c1 into :video_title; : if (SQLCODE != 0) break; /* SQLCODE refers to sqlca.sqlcode */ : /* host variables should have ':' prefix when they are used in DB2 commands */ : printf("%s\n",video_title); : } while (1); : EXEC SQL CLOSE c1; : EXEC SQL CONNECT RESET; : }

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