C Oracle記錄是一種非常重要的技術,在許多企業級應用程序中被廣泛使用。C語言是一種非常流行的高級編程語言,在許多操作系統和數據庫管理系統中都得到了廣泛的應用。Oracle是一種關系型數據庫管理系統,在許多企業中用于存儲和管理大量的數據。因此,使用C Oracle記錄技術可以幫助企業更好地管理和分析數據。
C Oracle記錄技術主要涉及以下幾個方面:
1. 連接Oracle數據庫
#include#include #include int main() { OCIEnv *envhp; OCIError *errhp; OCIServer *srvhp; OCIUserSession *usrhp; OCISession *seshp; text *username = "scott"; text *password = "tiger"; text *dsn = "ORCL"; OCIInitialize(OCI_DEFAULT); OCIHandleAlloc((dvoid *)OCIEnv, (dvoid **)&envhp, OCI_HTYPE_ENV, 0, NULL); OCIHandleAlloc(envhp, (dvoid **)&errhp, OCI_HTYPE_ERROR, 0, NULL); OCIHandleAlloc(envhp, (dvoid **)&srvhp, OCI_HTYPE_SERVER, 0, NULL); OCIHandleAlloc(envhp, (dvoid **)&usrhp, OCI_HTYPE_USER, 0, NULL); OCIHandleAlloc(envhp, (dvoid **)&seshp, OCI_HTYPE_SESSION, 0, NULL); OCIServerAttach(srvhp, errhp, (text *)dsn, strlen(dsn),OCI_DEFAULT); OCIAttrSet(usrhp, OCI_HTYPE_USER, username, strlen(username),OCI_ATTR_USERNAME, errhp); OCIAttrSet(usrhp, OCI_HTYPE_USER, password, strlen(password),OCI_ATTR_PASSWORD, errhp); OCIAttrSet(seshp, OCI_HTYPE_SESSION, usrhp, sizeof(OCIUserSession),OCI_ATTR_SESSION, errhp); OCISessionBegin(srvhp, errhp, seshp, OCI_CRED_RDBMS, OCI_DEFAULT); OCIHandleFree(srvhp, OCI_HTYPE_SERVER); OCIHandleFree(usrhp, OCI_HTYPE_USER); /*剩下的代碼將被“記一條”和“讀取”函數覆蓋*/ ... }
2. 記錄數據
在Oracle中,記錄(行)通常表示表中的一個條目。C Oracle記錄技術可以幫助我們使用C語言直接向Oracle數據庫中的表添加新的條目。
#define ROW_COUNT 10 int insert_rows(OCIEnv *envhp, OCIError *errhp, OCISvcCtx *svchp) { OCIStmt *stmthp; int i; OCIHandleAlloc((dvoid *)envhp, (dvoid **)&stmthp, OCI_HTYPE_STMT, 0, NULL); OCIStmtPrepare(stmthp, errhp, "INSERT INTO example_table VALUES (:1,:2)", strlen("INSERT INTO example_table VALUES (:1,:2)"), OCI_NTV_SYNTAX, OCI_DEFAULT); OCIStmtExecute(svchp, stmthp, errhp, ROW_COUNT, 0, NULL, NULL, OCI_COMMIT_ON_SUCCESS); for (i = 0; i< ROW_COUNT; i++) { OCIBind *bndp; int id = i + 1; OCIHandleAlloc(envhp, (dvoid **)&bndp, OCI_HTYPE_BIND, 0, NULL); OCIBindByPos(stmthp, &bndp, errhp, 1, &id, sizeof(id), SQLT_INT, NULL, NULL, NULL, 0, NULL, OCI_DEFAULT); OCIBindByPos(stmthp, &bndp, errhp, 2, "example data", strlen("example data"), SQLT_STR, NULL, NULL, NULL, 0, NULL, OCI_DEFAULT); OCIStmtExecute(svchp, stmthp, errhp, 1, 0, NULL, NULL, OCI_COMMIT_ON_SUCCESS); OCIBindFree(bndp); } OCIHandleFree(stmthp, OCI_HTYPE_STMT); return ROW_COUNT; }
3. 讀取數據
使用C Oracle記錄技術,我們可以從Oracle數據庫表中讀取數據,并將結果存儲為C結構體對象。這樣,我們就可以在編寫C程序時輕松地讀取Oracle數據庫中的數據。
#includestruct example { int id; char data[20]; }; int fetch_rows(OCIEnv *envhp, OCIError *errhp, OCISvcCtx *svchp, struct example *data) { OCIStmt *stmthp; int rows_fetched = 0; OCIHandleAlloc(envhp, (dvoid **)&stmthp, OCI_HTYPE_STMT, 0, NULL); OCIStmtPrepare(stmthp, errhp, "SELECT * FROM example_table", strlen("SELECT * FROM example_table"), OCI_NTV_SYNTAX, OCI_DEFAULT); OCIStmtExecute(svchp, stmthp, errhp, 0, 0, NULL, NULL, OCI_COMMIT_ON_SUCCESS); OCIDefine *defhp; OCIHandleAlloc(envhp, (dvoid **)&defhp, OCI_HTYPE_DEFINE, 0, NULL); OCIDefineByPos(stmthp, &defhp, errhp, 1, &data->id, sizeof(data->id), SQLT_INT, NULL, NULL, NULL, OCI_DEFAULT); OCIDefineByPos(stmthp, &defhp, errhp, 2, data->data, sizeof(data->data), SQLT_STR, NULL, NULL, NULL, OCI_DEFAULT); while (OCIStmtFetch(stmthp, errhp, 1, OCI_FETCH_NEXT, OCI_DEFAULT) == OCI_SUCCESS) { rows_fetched++; data++; } OCIHandleFree(stmthp, OCI_HTYPE_STMT); OCIHandleFree(defhp, OCI_HTYPE_DEFINE); return rows_fetched; }
正如您所看到的,使用C Oracle記錄技術可以幫助我們在C程序中輕松地連接到Oracle數據庫,并添加、讀取或編輯其中的數據。這種技術在許多企業級應用程序中得到了廣泛的應用,對于管理和分析大量的數據非常有用。