C语言实现Oracle数据库的写入功能（c 写入oracle）

C语言实现Oracle数据库的写入功能

在实际的开发过程中，很多时候需要使用数据库来存储和管理数据。Oracle数据库是目前比较流行和常用的数据库之一，它具有高性能、可靠性和扩展性等优点。本文将介绍如何使用C语言实现Oracle数据库的写入功能。

实现步骤如下：

1. 准备工作

在使用C语言操作Oracle数据库之前，需要先安装Oracle客户端库，并设置相应的环境变量。Oracle客户端库可以从Oracle官网下载，安装完成后需要将其路径添加到PATH环境变量中，这样才能在C代码中使用Oracle相关的头文件和库文件。

2. 建立连接

使用C语言连接Oracle数据库的过程与其他编程语言类似，需要先建立连接。以下是连接Oracle数据库的代码示例：

OCIDefine *defnp = (OCIDefine *) 0;
OCIEnv *envhp = (OCIEnv *) 0;
OCIStmt *stmthp = (OCIStmt *) 0;
OCISvcCtx *svchp = (OCISvcCtx *) 0;
OCIError *errhp = (OCIError *) 0;
OCISession *usrhp = (OCISession *) 0;
char *username = "your_username";
char *password = "your_password";
char *dbname = "your_database_name";
OCIBind *bndhp1 = (OCIBind *) 0, *bndhp2 = (OCIBind *) 0, *bndhp3 = (OCIBind *) 0;
int empno = 7839;
char ename[11] = "KING";
double sal = 5000;
char sqlstmt[100] = "INSERT INTO emp (empno, ename, sal) VALUES (:empno, :ename, :sal)";
    
OCIEnvCreate(&envhp, OCI_OBJECT|OCI_THREADED, (dvoid *) 0, 
    (dvoid * (*)(dvoid *, size_t)) malloc, (dvoid * (*)(dvoid *, dvoid *, size_t)) realloc, 
    (void (*)(dvoid *, dvoid *)) free, (size_t) 0, (dvoid **) 0);
OCIHandleAlloc((dvoid *) envhp, (dvoid **) &errhp, OCI_HTYPE_ERROR, (size_t) 0, (dvoid **) 0);
OCIHandleAlloc((dvoid *) envhp, (dvoid **) &svchp, OCI_HTYPE_SVCCTX, (size_t) 0, (dvoid **) 0);

OCIAttrSet((dvoid *) svchp, OCI_HTYPE_SVCCTX, (dvoid *) envhp, (ub4) 0, OCI_ATTR_ENV, errhp);
OCIHandleAlloc((dvoid *) envhp, (dvoid **) &stmthp, OCI_HTYPE_STMT, (size_t) 0, (dvoid **) 0);
OCIAttrSet((dvoid *) svchp, OCI_HTYPE_SVCCTX, (dvoid *) dbname, (ub4) strlen((char *) dbname), OCI_ATTR_SERVER_NAME, errhp);
    
OCIHandleAlloc((dvoid *) envhp, (void **) &bndhp1, (ub4) OCI_HTYPE_BIND, (size_t) 0, (void **) 0);
OCIHandleAlloc((dvoid *) envhp, (void **) &bndhp2, (ub4) OCI_HTYPE_BIND, (size_t) 0, (void **) 0);
OCIHandleAlloc((dvoid *) envhp, (void **) &bndhp3, (ub4) OCI_HTYPE_BIND, (size_t) 0, (void **) 0);
    
OCIAttrSet((dvoid *) stmthp, OCI_HTYPE_STMT, (dvoid *) sqlstmt, (ub4) strlen((char *) sqlstmt), OCI_ATTR_STATEMENT, errhp);

OCIStmtPrepare(stmthp, errhp, (OraText *) sqlstmt, (ub4) strlen((char *) sqlstmt), (ub4) OCI_NTV_SYNTAX, (ub4) OCI_DEFAULT);
OCIAttrSet((dvoid *) bndhp1, OCI_HTYPE_BIND, (dvoid *) &empno, (sb4) sizeof(empno), (ub4) SQLT_INT, (dvoid *) 0, (ub4 *) 0, (ub4 *) 0);
OCIAttrSet((dvoid *) bndhp2, OCI_HTYPE_BIND, (dvoid *) ename, (sb4) sizeof(ename), (ub4) SQLT_STR, (dvoid *) 0, (ub4 *) 0, (ub4 *) 0);
OCIAttrSet((dvoid *) bndhp3, OCI_HTYPE_BIND, (dvoid *) &sal, (sb4) sizeof(sal), (ub4) SQLT_FLT, (dvoid *) 0, (ub4 *) 0, (ub4 *) 0);
    
OCIStmtBindByPos(stmthp, &bndhp1, errhp, (ub4) 1, (dvoid *) &empno, (sb4) sizeof(empno), (ub2) SQLT_INT, (dvoid *) 0, (ub2 *) 0, (ub2 *) 0, (ub4) 0, (ub4 *) 0, (ub4) OCI_DEFAULT);
OCIStmtBindByPos(stmthp, &bndhp2, errhp, (ub4) 2, (dvoid *) ename, (sb4) strlen(ename), (ub2) SQLT_STR, (dvoid *) 0, (ub2 *) 0, (ub2 *) 0, (ub4) 0, (ub4 *) 0, (ub4) OCI_DEFAULT);
OCIStmtBindByPos(stmthp, &bndhp3, errhp, (ub4) 3, (dvoid *) &sal, (sb4) sizeof(sal), (ub2) SQLT_FLT, (dvoid *) 0, (ub2 *) 0, (ub2 *) 0, (ub4) 0, (ub4 *) 0, (ub4) OCI_DEFAULT);
OCIAttrSet((dvoid *) stmthp, OCI_HTYPE_STMT, (dvoid *) &defnp, (ub4) 0, OCI_ATTR_DEFINE, errhp);
OCIAttrSet((dvoid *) svchp, OCI_HTYPE_SVCCTX, (dvoid *) usrhp, (ub4) 0, OCI_ATTR_SESSION, errhp);
OCIStmtExecute(svchp, stmthp, errhp, (ub4) 1, (ub4) 0, (OCISnapshot *) NULL, (OCISnapshot *) NULL, OCI_DEFAULT);
OCIHandleFree((dvoid *) bndhp1, OCI_HTYPE_BIND);
OCIHandleFree((dvoid *) bndhp2, OCI_HTYPE_BIND);
OCIHandleFree((dvoid *) bndhp3, OCI_HTYPE_BIND);
OCIHandleFree((dvoid *) stmthp, OCI_HTYPE_STMT);
OCIHandleFree((dvoid *) svchp, OCI_HTYPE_SVCCTX);
OCIHandleFree((dvoid *) errhp, OCI_HTYPE_ERROR);
OCISessionEnd(svchp, errhp, usrhp, (ub4)OCI_DEFAULT);
OCIHandleFree((dvoid *)usrhp, (ub4) OCI_HTYPE_SESSION);
OCIHandleFree((dvoid *)envhp, OCI_HTYPE_ENV);

在上述代码中，首先使用OCIEnvCreate函数创建一个OCI环境句柄envhp，然后使用OCIHandleAlloc函数分别创建错误句柄errhp、服务句柄svchp和语句句柄stmthp，这些句柄都是后面操作Oracle数据库所必需的组件。接着使用OCIAttrSet函数设置服务句柄svchp的环境属性，并使用OCIAttrSet函数设置语句句柄stmthp的属性。然后使用OCIStmtPrepare函数对SQL语句进行准备操作，使用OCIStmtBindByPos函数绑定变量和参数，最后使用OCIStmtExecute函数执行SQL语句。

3. 执行SQL语句

在连接Oracle数据库并准备好SQL语句之后，就可以执行SQL语句将数据写入到数据库中了。以下是执行SQL语句写入数据的代码示例：

char *sql = "insert into employee (id, name, age) values (:id, :name, :age)";
OCIStmt *stmt;
ub2 in_out = OCI_DEFAULT;
ub4 rows_affected;
int id_value = 1;
char *name_value = "Tom";
int age_value = 25;
OCIParam *param = NULL;
OCIParam *errhp = NULL;
OCIHandleAlloc((dvoid *) envhp, (dvoid **) &stmt, OCI_HTYPE_STMT, 0, (dvoid **) 0);
OCIParse(stmt, errhp, (text *)