C和Oracle是两个非常重要的编程工具,可以用来实现大量的计算机应用程序。在一些特定的应用场合,我们需要将C语言程序和Oracle数据库进行集成操作来实现一些专业的功能。在这样的情况下,我们需要掌握如何使用C语言进行Oracle数据库的录入操作。
例如,一个人力资源系统需要通过C程序将新员工信息录入到Oracle数据库中。这时,我们可以使用OCI(Oracle C语言接口)完成该操作。首先,我们需要在C程序中声明OCI所需要的指针变量:
OCIEnv *envhp;
OCIError *errhp;
OCIServer *srvhp;
OCISession *usrhp;
OCIStmt *stmthp;
然后,我们需要建立与数据库的连接:
OCIEnvCreate(&envhp, OCI_THREADED, (dvoid *)0, (dvoid * (*)(dvoid *, size_t))0,
(dvoid * (*)(dvoid *, dvoid *, size_t))0, (void (*)(dvoid *, dvoid *))0, 0, (dvoid **)0);
OCIHandleAlloc((dvoid *)envhp, (dvoid **)&errhp, OCI_HTYPE_ERROR, 0, (dvoid **)0);
OCIHandleAlloc((dvoid *)envhp, (dvoid **)&srvhp, OCI_HTYPE_SERVER, 0, (dvoid **)0);
OCIHandleAlloc((dvoid *)envhp, (dvoid **)&usrhp, OCI_HTYPE_SESSION, 0, (dvoid **)0);
接下来,我们需要登录数据库并执行SQL语句:
char *username = "SCOTT";
char *password = "TIGER";
char *dbname = "ORCL";
OCIAttrSetName((dvoid *)srvhp, OCI_HTYPE_SERVER, (dvoid *)"dbname", (ub4)strlen((char *)"dbname"), OCI_ATTR_SERVICENAME, errhp);
OCIServerAttach(srvhp, errhp, (text *)dbname, strlen((char *)dbname), OCI_DEFAULT);
OCIAttrSet((dvoid *)usrhp, OCI_HTYPE_SESSION, (dvoid *)username, strlen(username), OCI_ATTR_USERNAME, errhp);
OCIAttrSet((dvoid *)usrhp, OCI_HTYPE_SESSION, (dvoid *)password, strlen(password), OCI_ATTR_PASSWORD, errhp);
OCISessionBegin(srvhp, errhp, usrhp, OCI_CRED_RDBMS, OCI_DEFAULT);
OCIHandleAlloc((dvoid *)envhp, (dvoid **)&stmthp, OCI_HTYPE_STMT, 0, (dvoid **)0);
OCIStmtPrepare(stmthp, errhp, "INSERT INTO emp(empno, ename, job, mgr, hiredate, sal, comm, deptno) VALUES (:1, :2, :3, :4, :5, :6, :7, :8)", (ub4)strlen("INSERT INTO emp(empno, ename, job, mgr, hiredate, sal, comm, deptno) VALUES (:1, :2, :3, :4, :5, :6, :7, :8)"), OCI_NTV_SYNTAX, OCI_DEFAULT);
最后,我们可以使用OCIBindByName函数绑定变量并执行SQL语句:
OCIBind *bnd1p, *bnd2p, *bnd3p, *bnd4p, *bnd5p, *bnd6p, *bnd7p, *bnd8p;
OCIStmtBindByPos(stmthp, &bnd1p, errhp, 1, (dvoid *)&empno, sizeof(empno), SQLT_INT, (dvoid *)0, (ub2 *)0, (ub2 *)0, OCI_DEFAULT);
OCIStmtBindByName(stmthp, &bnd2p, errhp, (text *)":ename", -1, (dvoid *)ename, sizeof(ename), SQLT_STR, (dvoid *)0, (ub2 *)0, (ub2 *)0, OCI_DEFAULT);
OCIStmtBindByName(stmthp, &bnd3p, errhp, (text *)":job", -1, (dvoid *)job, sizeof(job), SQLT_STR, (dvoid *)0, (ub2 *)0, (ub2 *)0, OCI_DEFAULT);
OCIStmtBindByName(stmthp, &bnd4p, errhp, (text *)":mgr", -1, (dvoid *)&mgr, sizeof(mgr), SQLT_INT, (dvoid *)0, (ub2 *)0, (ub2 *)0, OCI_DEFAULT);
OCIStmtBindByName(stmthp, &bnd5p, errhp, (text *)":hiredate", -1, (dvoid *)&hiredate, sizeof(hiredate), SQLT_DAT, (dvoid *)0, (ub2 *)0, (ub2 *)0, OCI_DEFAULT);
OCIStmtBindByName(stmthp, &bnd6p, errhp, (text *)":sal", -1, (dvoid *)&sal, sizeof(sal), SQLT_FLT, (dvoid *)0, (ub2 *)0, (ub2 *)0, OCI_DEFAULT);
OCIStmtBindByName(stmthp, &bnd7p, errhp, (text *)":comm", -1, (dvoid *)&comm, sizeof(comm), SQLT_FLT, (dvoid *)0, (ub2 *)0, (ub2 *)0, OCI_DEFAULT);
OCIStmtBindByName(stmthp, &bnd8p, errhp, (text *)":deptno", -1, (dvoid *)&deptno, sizeof(deptno), SQLT_INT, (dvoid *)0, (ub2 *)0, (ub2 *)0, OCI_DEFAULT);
OCIStmtExecute(usrhp, stmthp, errhp, 1, 0, (OCISnapshot *)NULL, (OCISnapshot *)NULL, OCI_DEFAULT);
总之,使用C语言进行Oracle数据库录入操作需要了解OCI接口的基本知识,掌握连接、登录、SQL语句的执行以及变量绑定等操作,并且需要按照Oracle官方文档指导进行程序编写。只有这样才能够快速高效地完成数据库录入操作,提高生产效率。