Oracle临时表C语言操作体验(c oracle 临时表)

Oracle临时表:C语言操作体验

Oracle数据库是一种关系型数据库管理系统,为数据存储提供了高效和可靠的解决方案。Oracle还提供了一种临时表的概念,这种表在创建它们的会话结束时被删除。在本文中,我们将探讨如何使用C语言来操作Oracle临时表。

我们需要使用Oracle提供的C语言API连接到数据库。以下是一个简单的连接示例:

“`c

#include

#include

#include

int mn()

{

OCIEnv* envhp;

OCIServer* srvhp;

OCISession* sesshp;

OCIError* errhp;

sword status;

OCIInitialize(OCI_DEFAULT, NULL, NULL, NULL, NULL);

OCIEnvInit(&envhp, OCI_DEFAULT);

OCIHandleAlloc((dvoid*)envhp, (dvoid**)&errhp, OCI_HTYPE_ERROR, (size_t)0, (dvoid**)0);

OCIHandleAlloc((dvoid*)envhp, (dvoid**)&srvhp, OCI_HTYPE_SERVER, (size_t)0, (dvoid**)0);

OCIHandleAlloc((dvoid*)envhp, (dvoid**)&sesshp, OCI_HTYPE_SESSION, (size_t)0, (dvoid**)0);

OCIServerAttach(srvhp, errhp, “”, strlen(“”), OCI_DEFAULT);

OCISessionBegin(envhp, errhp, sesshp, OCI_CRED_RDBMS, OCI_DEFAULT, “”, strlen(“”), “”, strlen(“”));

OCISessionEnd(envhp, errhp, sesshp, OCI_DEFAULT);

OCIServerDetach(srvhp, errhp, OCI_DEFAULT);

OCIHandleFree((dvoid*)errhp, OCI_HTYPE_ERROR);

OCIHandleFree((dvoid*)sesshp, OCI_HTYPE_SESSION);

OCIHandleFree((dvoid*)srvhp, OCI_HTYPE_SERVER);

OCIHandleFree((dvoid*)envhp, OCI_HTYPE_ENV);

return 0;

}


在连接到数据库后,我们可以使用OCIStmtPrepare函数执行SQL语句。以下是一个示例,用于创建一个临时表:

```c
OCIStmt* stmtp;
char* create_temp_table = "create global temporary table temp_table (id number(10), name varchar(50)) on commit delete rows";
OCIStmtPrepare(stmthp, errhp, (OraText*)create_temp_table, strlen(create_temp_table), OCI_NTV_SYNTAX, OCI_DEFAULT);
OCIStmtExecute(svchp, stmtp, errhp, 0, 0, NULL, NULL, OCI_DEFAULT);

创建完成后,我们可以向临时表中插入数据:

“`c

char* insert_data = “insert into temp_table (id, name) values (:1, :2)”;

int id = 1;

char* name = “John”;

OCIStmtPrepare(stmthp, errhp, (OraText*)insert_data, strlen(insert_data), OCI_NTV_SYNTAX, OCI_DEFAULT);

OCIBindByPos(stmtp, &bind1p, errhp, 1, &id, sizeof(id), SQLT_INT, NULL, NULL, NULL, 0, NULL, OCI_DEFAULT);

OCIBindByPos(stmtp, &bind2p, errhp, 2, name, strlen(name), SQLT_STR, NULL, NULL, NULL, 0, NULL, OCI_DEFAULT);

OCIStmtExecute(svchp, stmtp, errhp, 1, 0, NULL, NULL, OCI_DEFAULT);


然后我们可以查询临时表中的数据:

```c
char* select_data = "select * from temp_table";
ociStmtPrepare(stmtp, errhp, (OraText*)select_data, strlen(select_data), OCI_NTV_SYNTAX, OCI_DEFAULT);
OCIStmtExecute(svchp, stmtp, errhp, 0, 0, NULL, NULL, OCI_DEFAULT);
OCIParam* paramhp;
ub4 row_count;
ub2 column_count;
OCIAttrGet(stmtp, OCI_HTYPE_STMT, &row_count, 0, OCI_ATTR_ROW_COUNT, errhp);
OCIAttrGet(stmtp, OCI_HTYPE_STMT, &paramhp, 0, OCI_ATTR_PARAM_COUNT, errhp);
column_count = (ub2)paramhp;
int id;
char* name;
OCIDefine* define1p;
OCIDefine* define2p;
OCIDefineByPos(stmtp, &define1p, errhp, 1, &id, sizeof(id), SQLT_INT, NULL, NULL, NULL, OCI_DEFAULT);
OCIDefineByPos(stmtp, &define2p, errhp, 2, name, sizeof(name), SQLT_STR, NULL, NULL, NULL, OCI_DEFAULT);
char output[1024];
sprintf(output, "The result set contns %d rows and %d columns\n", row_count, column_count);
printf(output);

while (OCIStmtFetch(stmtp, errhp, 1, OCI_FETCH_NEXT, OCI_DEFAULT) == OCI_SUCCESS)
{
sprintf(output, "ID: %d, Name: %s\n", id, name);
printf(output);
}

我们可以使用OCIStmtExecute函数删除临时表:

“`c

char* drop_temp_table = “drop table temp_table”;

OCIStmtPrepare(stmthp, errhp, (OraText*)drop_temp_table, strlen(drop_temp_table), OCI_NTV_SYNTAX, OCI_DEFAULT);

OCIStmtExecute(svchp, stmtp, errhp, 0, 0, NULL, NULL, OCI_DEFAULT);


通过以上过程,我们可以使用C语言来操作Oracle临时表,完成数据的快速存取。

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