c 执行oracle游标

执行Oracle游标是C语言开发人员操作Oracle数据库的重要技能之一。

游标是Oracle数据库中用来处理和获取数据的重要工具。在C程序中，当需要获取Oracle数据库中的数据时，使用游标可以指定获取某个表中的某些数据，或者获取数据库中多个表中的相关数据。使用游标可以避免一次性获取大量的数据，从而提高程序的性能。

下面是使用C语言执行Oracle游标的示例代码：

#include#include#include#includeint main() { OCIEnv *env; OCISrvCtx *srv; OCIError *err; OCISession *ses; OCISvcCtx *svc; OCIStmt *stmt; OCIStmt *stmt1; OCIDefine *def; OCIBind *bind; OCIParam *param; sword status; char user[50]; char pass[50]; char dbname[50]; char query[256]; char temp[50]; int id; int count; char name[50]; double price; //初始化OCI环境、服务上下文、错误句柄等 OCIEnvCreate(&env, OCI_THREADED|OCI_OBJECT, NULL, NULL, NULL, NULL, 0, NULL); OCIHandleAlloc(env, (void**)&srv, OCI_HTYPE_SERVER, 0, NULL); OCIHandleAlloc(env, (void**)&err, OCI_HTYPE_ERROR, 0, NULL); OCIHandleAlloc(env, (void**)&ses, OCI_HTYPE_SESSION, 0, NULL); OCIHandleAlloc(env, (void**)&svc, OCI_HTYPE_SVCCTX, 0, NULL); OCIHandleAlloc(env, (void**)&stmt, OCI_HTYPE_STMT, 0, NULL); OCIHandleAlloc(env, (void**)&stmt1, OCI_HTYPE_STMT, 0, NULL); //指定数据库用户名、密码、连接字符串 strcpy(user, "scott"); strcpy(pass, "tiger"); strcpy(dbname, "ORCL"); //连接数据库 OCILogon2(env, err, &svc, user, strlen(user), pass, strlen(pass), dbname, strlen(dbname), OCI_DEFAULT); //创建游标 sprintf(query, "BEGIN OPEN :1 FOR SELECT * FROM PRODUCTS; END;"); OCIStmtPrepare(stmt1, err, query, strlen(query), OCI_NTV_SYNTAX, OCI_DEFAULT); OCIStmtExecute(svc, stmt1, err, 1, 0, NULL, NULL, OCI_STMT_SCROLLABLE_READONLY); OCIParamGet(stmt1, OCI_HTYPE_STMT, err, (void**)¶m, 1); //设置游标 OCIAttrGet(param, OCI_DTYPE_PARAM, (void**)&stmt, 0, OCI_ATTR_CURSOR, err); sprintf(query, "FETCH :1 INTO :2, :3, :4;"); OCIStmtPrepare(stmt, err, query, strlen(query), OCI_NTV_SYNTAX, OCI_DEFAULT); //绑定游标参数 OCIBindByName(stmt, &bind, err, (OraText *) ":1", strlen(":1"), (void *) &id, sizeof(int), SQLT_INT, NULL, NULL, NULL, 0, NULL, OCI_DEFAULT); OCIAttrSet(bind, OCI_HTYPE_BIND, (void*)&def, 0, OCI_ATTR_DEFINE, err); OCIAttrSet(def, OCI_DTYPE_PARAM, (void*)&count, sizeof(count), OCI_ATTR_DATA_SIZE, err); //绑定结果集参数 OCIBindByName(stmt, &bind, err, (OraText *) ":2", strlen(":2"), (void *)name, sizeof(name), SQLT_STR, NULL, NULL, NULL, 0, NULL, OCI_DEFAULT); OCIAttrSet(bind, OCI_HTYPE_BIND, (void*)&def, 0, OCI_ATTR_DEFINE, err); OCIAttrSet(def, OCI_DTYPE_PARAM, (void*)&count, sizeof(count), OCI_ATTR_DATA_SIZE, err); OCIBindByName(stmt, &bind, err, (OraText *) ":3", strlen(":3"), (void *) &price, sizeof(double), SQLT_FLT, NULL, NULL, NULL, 0, NULL, OCI_DEFAULT); OCIAttrSet(bind, OCI_HTYPE_BIND, (void*)&def, 0, OCI_ATTR_DEFINE, err); OCIAttrSet(def, OCI_DTYPE_PARAM, (void*)&count, sizeof(count), OCI_ATTR_DATA_SIZE, err); //执行游标 OCIStmtExecute(svc, stmt, err, 0, 0, NULL, NULL, OCI_FETCH_NEXT); while (status != OCI_NO_DATA) { printf("Product ID: %d, Product Name: %s, Product Price: %0.2f\n", id, name, price); status = OCIStmtFetch2(stmt, err, 1, OCI_FETCH_NEXT, 0, OCI_DEFAULT); } //关闭游标和数据库连接 OCIStmtClose(stmt, err); OCIStmtClose(stmt1, err); OCILogoff(svc, err); OCIHandleFree(srv, OCI_HTYPE_SERVER); OCIHandleFree(err, OCI_HTYPE_ERROR); OCIHandleFree(ses, OCI_HTYPE_SESSION); OCIHandleFree(svc, OCI_HTYPE_SVCCTX); OCIHandleFree(stmt, OCI_HTYPE_STMT); OCIHandleFree(stmt1, OCI_HTYPE_STMT); return 0; }