C oracle api是为了简化与Oracle数据库的交互而设计的一组API接口。它可以帮助开发人员简化数据管理、查询和存储等重要工作。C oracle api还可以允许开发人员通过外部C程序来直接与Oracle数据库进行通信。
为了更好地了解C oracle api的使用，以下是一些使用C oracle api时常用的代码示例：
// 连接到Oracle数据库
OCIDefine handle;
OCIStmt stmt;
//...
// 创建数据库连接指针
OCIEnvCreate(&env, OCI_DEFAULT, (dvoid *) 0,
(dvoid * (*)(void *, size_t)) 0,
(dvoid * (*)(void *, void *, size_t)) 0,
(void (*)(void *, void *)) 0, 0, (dvoid **)0);
OCIHandleAlloc((dvoid *)env, (dvoid **)&err, OCI_HTYPE_ERROR, (size_t)0, (dvoid **)0);
OCIHandleAlloc((dvoid *)env, (dvoid **)&srv, OCI_HTYPE_SERVER, (size_t)0, (dvoid **)0);
OCIHandleAlloc((dvoid *)env, (dvoid **)&svc, OCI_HTYPE_SVCCTX, (size_t)0, (dvoid **)0);
OCIHandleAlloc((dvoid *)env, (dvoid **)&authp, OCI_HTYPE_SESSION, (size_t)0, (dvoid **)0);
OCIServerAttach(srv, err, (const OraText *)"//127.0.0.1:1521/orcl", strlen("//127.0.0.1:1521/orcl"), OCI_DEFAULT);
OCIAttrSet((dvoid *)svc, OCI_HTYPE_SVCCTX, (dvoid *)srv, (ub4)0, OCI_ATTR_SERVER, err);
OCIAttrSet((dvoid *)authp, OCI_HTYPE_SESSION, (dvoid *)"test", strlen("test"), OCI_ATTR_USERNAME, err);
OCIAttrSet((dvoid *)authp, OCI_HTYPE_SESSION, (dvoid *)"123456", strlen("123456"), OCI_ATTR_PASSWORD, err);
OCISessionBegin(svc, err, authp, OCI_CRED_RDBMS, OCI_DEFAULT);
OCIAttrSet((dvoid *)svc, OCI_HTYPE_SVCCTX, (dvoid *)authp, (ub4)0, OCI_ATTR_SESSION, err);
// 查询数据
char str_sql[256]="select test1, test2 from userinfo";
OCIResult* p_result;
OCIStmt* p_stmt;
OCIDefine* p_define=NULL;
OCIBind p_bind2[2];
sb4 s_res=0;
OCIHandleAlloc( (dvoid *)env, (dvoid **)&stmt, OCI_HTYPE_STMT, (size_t)0, (dvoid **)0 );
if(OCIStmtPrepare(stmt, err, (text*)str_sql, strlen(str_sql), OCI_NTV_SYNTAX, OCI_DEFAULT)!=OCI_SUCCESS)
{
printf("SQL Error: Statement couldn't be prepared\n");
}
OCIParamGet(stmt, OCI_HTYPE_STMT, err, (void **)&p_result, 1);
OCIAttrGet(p_result, OCI_DTYPE_PARAM, (void **)&p_define[0], (ub4*)0, OCI_ATTR_NAME, err);
OCIAttrGet(p_result, OCI_DTYPE_PARAM, (void **)&p_define[1], (ub4*)0, OCI_ATTR_NAME, err);
OCIDefineByPos(stmt, &p_define[0], err, 1, NULL, 0, SQLT_STR, NULL, NULL, NULL, OCI_DEFAULT);
OCIDefineByPos(stmt, &p_define[1], err, 2, NULL, 0, SQLT_NUM, NULL, NULL, NULL, OCI_DEFAULT);
if(OCIDefineByPos(stmt, &p_define[0], err, 1, NULL, 0, SQLT_STR, NULL, NULL, NULL, OCI_DEFAULT)!=OCI_SUCCESS)
{
OCIHandleFree(stmt, OCI_HTYPE_STMT);
printf("SQL Error: Binding statements failed\n");
}
if(OCIDefineByPos(stmt, &p_define[1], err, 2, NULL, 0, SQLT_NUM, NULL, NULL, NULL, OCI_DEFAULT)!=OCI_SUCCESS)
{
OCIHandleFree(stmt, OCI_HTYPE_STMT);
printf("SQL Error: Binding statements failed\n");
}
/* Execute the SQL statement */
if(OCIStmtExecute(svc, stmt, err, (ub4)1, (ub4)0, (CONST OCISnapshot*)NULL, (OCISnapshot*)NULL, OCI_COMMIT_ON_SUCCESS)!=OCI_SUCCESS)
{
OCIHandleFree(stmt, OCI_HTYPE_STMT);
printf("SQL Error: Statement execution failed\n");
}
/* Fetch the rows */
while((s_res = OCIStmtFetch(stmt, err, 1, OCI_FETCH_NEXT, OCI_DEFAULT))!=OCI_NO_DATA)
{
printf("Name: %s, Test result: %d\n", sql_names, sql_tests);
}
// 关闭数据库连接
OCILogoff(svc, err);
C oracle api还包含很多其他的操作，如事务管理、分页查询等，可以帮助开发人员更好地操作数据库。如果您是一个在使用Oracle数据库的开发人员，那么了解C oracle api是一个非常好的选择。除了上述示例外，Oracle官方文档和其他开发社区也提供了丰富的资源及例子供开发人员使用。希望本文对您的学习和开发有所帮助。
