示例

常用功能示例代码

  1. // 此示例演示如何通过ODBC方式获取openGauss中的数据。
  2. // DBtest.c (compile with: libodbc.so)   
  3. #include <stdlib.h> 
  4. #include <stdio.h> 
  5. #include <sqlext.h>
  6. #ifdef WIN32
  7. #include <windows.h>
  8. #endif 
  9. SQLHENV       V_OD_Env;        // Handle ODBC environment 
  10. SQLHSTMT      V_OD_hstmt;      // Handle statement 
  11. SQLHDBC       V_OD_hdbc;       // Handle connection     
  12. char          typename[100];
  13. SQLINTEGER    value = 100;
  14. SQLINTEGER    V_OD_erg,V_OD_buffer,V_OD_err,V_OD_id;
  15. int main(int argc,char *argv[]) 
  16. {         
  17.       // 1. 申请环境句柄       
  18.       V_OD_erg = SQLAllocHandle(SQL_HANDLE_ENV,SQL_NULL_HANDLE,&V_OD_Env);     
  19.       if ((V_OD_erg != SQL_SUCCESS) && (V_OD_erg != SQL_SUCCESS_WITH_INFO))        
  20.       {           
  21.            printf("Error AllocHandle\n");           
  22.            exit(0);        
  23.       } 
  24.       // 2. 设置环境属性（版本信息）         
  25.       SQLSetEnvAttr(V_OD_Env, SQL_ATTR_ODBC_VERSION, (void*)SQL_OV_ODBC3, 0);      
  26.       // 3. 申请连接句柄        
  27.       V_OD_erg = SQLAllocHandle(SQL_HANDLE_DBC, V_OD_Env, &V_OD_hdbc);     
  28.       if ((V_OD_erg != SQL_SUCCESS) && (V_OD_erg != SQL_SUCCESS_WITH_INFO))      
  29.       {                     
  30.            SQLFreeHandle(SQL_HANDLE_ENV, V_OD_Env);          
  31.            exit(0);       
  32.       }
  33.       // 4. 设置连接属性
  34.       SQLSetConnectAttr(V_OD_hdbc, SQL_ATTR_AUTOCOMMIT, SQL_AUTOCOMMIT_ON, 0);          
  35.       // 5. 连接数据源，这里的“userName”与“password”分别表示连接数据库的用户名和用户密码，请根据实际情况修改。
  36.       // 如果odbc.ini文件中已经配置了用户名密码，那么这里可以留空（""）；但是不建议这么做，因为一旦odbc.ini权限管理不善，将导致数据库用户密码泄露。    
  37.       V_OD_erg = SQLConnect(V_OD_hdbc, (SQLCHAR*) "gaussdb", SQL_NTS,  
  38.                            (SQLCHAR*) "userName", SQL_NTS,  (SQLCHAR*) "password", SQL_NTS);        
  39.       if ((V_OD_erg != SQL_SUCCESS) && (V_OD_erg != SQL_SUCCESS_WITH_INFO))      
  40.       {           
  41.           printf("Error SQLConnect %d\n",V_OD_erg);            
  42.           SQLFreeHandle(SQL_HANDLE_ENV, V_OD_Env);       
  43.           exit(0);        
  44.       }     
  45.       printf("Connected !\n"); 
  46.       // 6. 设置语句属性
  47.       SQLSetStmtAttr(V_OD_hstmt,SQL_ATTR_QUERY_TIMEOUT,(SQLPOINTER *)3,0);
  48.       // 7. 申请语句句柄
  49.       SQLAllocHandle(SQL_HANDLE_STMT, V_OD_hdbc, &V_OD_hstmt);       
  50.       // 8. 直接执行SQL语句。
  51.       SQLExecDirect(V_OD_hstmt,"drop table IF EXISTS customer_t1",SQL_NTS);
  52.       SQLExecDirect(V_OD_hstmt,"CREATE TABLE customer_t1(c_customer_sk INTEGER, c_customer_name VARCHAR(32));",SQL_NTS);
  53.       SQLExecDirect(V_OD_hstmt,"insert into customer_t1 values(25,li)",SQL_NTS);
  54.       // 9. 准备执行
  55.       SQLPrepare(V_OD_hstmt,"insert into customer_t1 values(?)",SQL_NTS); 
  56.       // 10. 绑定参数
  57.       SQLBindParameter(V_OD_hstmt,1,SQL_PARAM_INPUT,SQL_C_SLONG,SQL_INTEGER,0,0,
  58.                        &value,0,NULL);
  59.       // 11. 执行准备好的语句
  60.       SQLExecute(V_OD_hstmt);
  61.       SQLExecDirect(V_OD_hstmt,"select id from testtable",SQL_NTS);
  62.       // 12. 获取结果集某一列的属性
  63.       SQLColAttribute(V_OD_hstmt,1,SQL_DESC_TYPE,typename,100,NULL,NULL);                 
  64.       printf("SQLColAtrribute %s\n",typename);
  65.       // 13. 绑定结果集
  66.       SQLBindCol(V_OD_hstmt,1,SQL_C_SLONG, (SQLPOINTER)&V_OD_buffer,150,
  67.                 (SQLLEN *)&V_OD_err);
  68.       // 14. 通过SQLFetch取结果集中数据
  69.       V_OD_erg=SQLFetch(V_OD_hstmt);
  70.       // 15. 通过SQLGetData获取并返回数据。
  71.       while(V_OD_erg != SQL_NO_DATA)
  72.       {
  73.           SQLGetData(V_OD_hstmt,1,SQL_C_SLONG,(SQLPOINTER)&V_OD_id,0,NULL);
  74.           printf("SQLGetData ----ID = %d\n",V_OD_id);
  75.           V_OD_erg=SQLFetch(V_OD_hstmt);
  76.       };
  77.       printf("Done !\n");
  78.       // 16. 断开数据源连接并释放句柄资源
  79.       SQLFreeHandle(SQL_HANDLE_STMT,V_OD_hstmt);    
  80.       SQLDisconnect(V_OD_hdbc);         
  81.       SQLFreeHandle(SQL_HANDLE_DBC,V_OD_hdbc);       
  82.       SQLFreeHandle(SQL_HANDLE_ENV, V_OD_Env);  
  83.       return(0);
  84.  }

批量绑定示例代码

  1. /**********************************************************************
  2. * 请在数据源中打开UseBatchProtocol，同时指定数据库中参数support_batch_bind
  3. * 为on
  4. * CHECK_ERROR的作用是检查并打印错误信息。
  5. * 此示例将与用户交互式获取DSN、模拟的数据量，忽略的数据量，并将最终数据入库到test_odbc_batch_insert中
  6. ***********************************************************************/
  7. #include <stdio.h>
  8. #include <stdlib.h>
  9. #include <sql.h>
  10. #include <sqlext.h>
  11. #include <string.h>
  13. #include "util.c"
  15. void Exec(SQLHDBC hdbc, SQLCHAR* sql)
  16. {
  17.     SQLRETURN retcode;                  // Return status
  18.     SQLHSTMT hstmt = SQL_NULL_HSTMT;    // Statement handle
  19.     SQLCHAR     loginfo[2048];
  21.     // Allocate Statement Handle
  22.     retcode = SQLAllocHandle(SQL_HANDLE_STMT, hdbc, &hstmt);
  23.     CHECK_ERROR(retcode, "SQLAllocHandle(SQL_HANDLE_STMT)",
  24.                 hstmt, SQL_HANDLE_STMT);
  26.     // Prepare Statement
  27.     retcode = SQLPrepare(hstmt, (SQLCHAR*) sql, SQL_NTS);
  28.     sprintf((char*)loginfo, "SQLPrepare log: %s", (char*)sql);
  29.     CHECK_ERROR(retcode, loginfo, hstmt, SQL_HANDLE_STMT);
  31.     // Execute Statement
  32.     retcode = SQLExecute(hstmt);
  33.     sprintf((char*)loginfo, "SQLExecute stmt log: %s", (char*)sql);
  34.     CHECK_ERROR(retcode, loginfo, hstmt, SQL_HANDLE_STMT);
  36.     // Free Handle
  37.     retcode = SQLFreeHandle(SQL_HANDLE_STMT, hstmt);
  38.     sprintf((char*)loginfo, "SQLFreeHandle stmt log: %s", (char*)sql);
  39.     CHECK_ERROR(retcode, loginfo, hstmt, SQL_HANDLE_STMT);
  40. }
  42. int main () 
  43. {
  44.     SQLHENV  henv  = SQL_NULL_HENV;
  45.     SQLHDBC  hdbc  = SQL_NULL_HDBC; 
  46.     int      batchCount = 1000;
  47.     SQLLEN   rowsCount = 0;
  48.     int      ignoreCount = 0;
  50.     SQLRETURN   retcode;
  51.     SQLCHAR     dsn[1024] = {'\0'};
  52.     SQLCHAR     loginfo[2048];
  54.     // 交互获取数据源名称
  55.     getStr("Please input your DSN", (char*)dsn, sizeof(dsn), 'N');
  56.     // 交互获取批量绑定的数据量
  57.     getInt("batchCount", &batchCount, 'N', 1);
  58.     do 
  59.     {
  60.         // 交互获取批量绑定的数据中，不要入库的数据量
  61.         getInt("ignoreCount", &ignoreCount, 'N', 1);
  62.         if (ignoreCount > batchCount)
  63.         {
  64.             printf("ignoreCount(%d) should be less than batchCount(%d)\n", ignoreCount, batchCount);
  65.         }
  66.     }while(ignoreCount > batchCount);
  68.     retcode = SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &henv);
  69.     CHECK_ERROR(retcode, "SQLAllocHandle(SQL_HANDLE_ENV)",
  70.                 henv, SQL_HANDLE_ENV);
  72.     // Set ODBC Verion
  73.     retcode = SQLSetEnvAttr(henv, SQL_ATTR_ODBC_VERSION,
  74.                                         (SQLPOINTER*)SQL_OV_ODBC3, 0);
  75.     CHECK_ERROR(retcode, "SQLSetEnvAttr(SQL_ATTR_ODBC_VERSION)",
  76.                 henv, SQL_HANDLE_ENV);
  78.     // Allocate Connection
  79.     retcode = SQLAllocHandle(SQL_HANDLE_DBC, henv, &hdbc);
  80.     CHECK_ERROR(retcode, "SQLAllocHandle(SQL_HANDLE_DBC)",
  81.                 henv, SQL_HANDLE_DBC);
  83.     // Set Login Timeout
  84.     retcode = SQLSetConnectAttr(hdbc, SQL_LOGIN_TIMEOUT, (SQLPOINTER)5, 0);
  85.     CHECK_ERROR(retcode, "SQLSetConnectAttr(SQL_LOGIN_TIMEOUT)",
  86.                 hdbc, SQL_HANDLE_DBC);
  88.     // Set Auto Commit
  89.     retcode = SQLSetConnectAttr(hdbc, SQL_ATTR_AUTOCOMMIT,
  90.                                         (SQLPOINTER)(1), 0);
  91.     CHECK_ERROR(retcode, "SQLSetConnectAttr(SQL_ATTR_AUTOCOMMIT)",
  92.                 hdbc, SQL_HANDLE_DBC);
  94.     // Connect to DSN
  95.     sprintf(loginfo, "SQLConnect(DSN:%s)", dsn);
  96.     retcode = SQLConnect(hdbc, (SQLCHAR*) dsn, SQL_NTS,
  97.                                (SQLCHAR*) NULL, 0, NULL, 0);
  98.     CHECK_ERROR(retcode, loginfo, hdbc, SQL_HANDLE_DBC);
  100.     // init table info.
  101.     Exec(hdbc, "drop table if exists test_odbc_batch_insert");
  102.     Exec(hdbc, "create table test_odbc_batch_insert(id int primary key, col varchar2(50))");
  104.     // 下面的代码根据用户输入的数据量，构造出将要入库的数据:
  105.     {
  106.         SQLRETURN retcode; 
  107.         SQLHSTMT hstmtinesrt = SQL_NULL_HSTMT;
  108.         int          i;
  109.         SQLCHAR      *sql = NULL;
  110.         SQLINTEGER   *ids  = NULL;
  111.         SQLCHAR      *cols = NULL;
  112.         SQLLEN       *bufLenIds = NULL;
  113.         SQLLEN       *bufLenCols = NULL;
  114.         SQLUSMALLINT *operptr = NULL;
  115.         SQLUSMALLINT *statusptr = NULL;
  116.         SQLULEN      process = 0;
  118.         // 这里是按列构造，每个字段的内存连续存放在一起。
  119.         ids = (SQLINTEGER*)malloc(sizeof(ids[0]) * batchCount);
  120.         cols = (SQLCHAR*)malloc(sizeof(cols[0]) * batchCount * 50);
  121.         // 这里是每个字段中，每一行数据的内存长度。
  122.         bufLenIds = (SQLLEN*)malloc(sizeof(bufLenIds[0]) * batchCount);
  123.         bufLenCols = (SQLLEN*)malloc(sizeof(bufLenCols[0]) * batchCount);
  124.         // 该行是否需要被处理，SQL_PARAM_IGNORE 或 SQL_PARAM_PROCEED
  125.         operptr = (SQLUSMALLINT*)malloc(sizeof(operptr[0]) * batchCount);
  126.         memset(operptr, 0, sizeof(operptr[0]) * batchCount);
  127.         // 该行的处理结果。
  128.         // 注：由于数据库中处理方式是同一语句隶属同一事务中，所以如果出错，那么待处理数据都将是出错的，并不会部分入库。
  129.         statusptr = (SQLUSMALLINT*)malloc(sizeof(statusptr[0]) * batchCount);
  130.         memset(statusptr, 88, sizeof(statusptr[0]) * batchCount);
  132.         if (NULL == ids || NULL == cols || NULL == bufLenCols || NULL == bufLenIds)
  133.         {
  134.             fprintf(stderr, "FAILED:\tmalloc data memory failed\n");
  135.             goto exit;
  136.         }
  138.         for (int i = 0; i < batchCount; i++)
  139.         {
  140.             ids[i] = i;
  141.             sprintf(cols + 50 * i, "column test value %d", i);
  142.             bufLenIds[i] = sizeof(ids[i]);
  143.             bufLenCols[i] = strlen(cols + 50 * i);
  144.             operptr[i] = (i < ignoreCount) ? SQL_PARAM_IGNORE : SQL_PARAM_PROCEED;
  145.         }
  147.         // Allocate Statement Handle
  148.         retcode = SQLAllocHandle(SQL_HANDLE_STMT, hdbc, &hstmtinesrt);
  149.         CHECK_ERROR(retcode, "SQLAllocHandle(SQL_HANDLE_STMT)",
  150.                     hstmtinesrt, SQL_HANDLE_STMT);
  152.         // Prepare Statement
  153.         sql = (SQLCHAR*)"insert into test_odbc_batch_insert values(?, ?)";
  154.         retcode = SQLPrepare(hstmtinesrt, (SQLCHAR*) sql, SQL_NTS);
  155.         sprintf((char*)loginfo, "SQLPrepare log: %s", (char*)sql);
  156.         CHECK_ERROR(retcode, loginfo, hstmtinesrt, SQL_HANDLE_STMT);
  158.         retcode = SQLSetStmtAttr(hstmtinesrt, SQL_ATTR_PARAMSET_SIZE, (SQLPOINTER)batchCount, sizeof(batchCount));
  159.         CHECK_ERROR(retcode, "SQLSetStmtAttr", hstmtinesrt, SQL_HANDLE_STMT);
  161.         retcode = SQLBindParameter(hstmtinesrt, 1, SQL_PARAM_INPUT, SQL_C_SLONG, SQL_INTEGER, sizeof(ids[0]), 0,&(ids[0]), 0, bufLenIds);
  162.         CHECK_ERROR(retcode, "SQLBindParameter for id", hstmtinesrt, SQL_HANDLE_STMT);
  164.         retcode = SQLBindParameter(hstmtinesrt, 2, SQL_PARAM_INPUT, SQL_C_CHAR, SQL_CHAR, 50, 50, cols, 50, bufLenCols);
  165.         CHECK_ERROR(retcode, "SQLBindParameter for cols", hstmtinesrt, SQL_HANDLE_STMT);
  167.         retcode = SQLSetStmtAttr(hstmtinesrt, SQL_ATTR_PARAMS_PROCESSED_PTR, (SQLPOINTER)&process, sizeof(process));
  168.         CHECK_ERROR(retcode, "SQLSetStmtAttr for SQL_ATTR_PARAMS_PROCESSED_PTR", hstmtinesrt, SQL_HANDLE_STMT);
  170.         retcode = SQLSetStmtAttr(hstmtinesrt, SQL_ATTR_PARAM_STATUS_PTR, (SQLPOINTER)statusptr, sizeof(statusptr[0]) * batchCount);
  171.         CHECK_ERROR(retcode, "SQLSetStmtAttr for SQL_ATTR_PARAM_STATUS_PTR", hstmtinesrt, SQL_HANDLE_STMT);
  173.         retcode = SQLSetStmtAttr(hstmtinesrt, SQL_ATTR_PARAM_OPERATION_PTR, (SQLPOINTER)operptr, sizeof(operptr[0]) * batchCount);
  174.         CHECK_ERROR(retcode, "SQLSetStmtAttr for SQL_ATTR_PARAM_OPERATION_PTR", hstmtinesrt, SQL_HANDLE_STMT);
  176.         retcode = SQLExecute(hstmtinesrt);
  177.         sprintf((char*)loginfo, "SQLExecute stmt log: %s", (char*)sql);
  178.         CHECK_ERROR(retcode, loginfo, hstmtinesrt, SQL_HANDLE_STMT);
  180.         retcode = SQLRowCount(hstmtinesrt, &rowsCount);
  181.         CHECK_ERROR(retcode, "SQLRowCount execution", hstmtinesrt, SQL_HANDLE_STMT);
  183.         if (rowsCount != (batchCount - ignoreCount))
  184.         {
  185.             sprintf(loginfo, "(batchCount - ignoreCount)(%d) != rowsCount(%d)", (batchCount - ignoreCount), rowsCount);
  186.             CHECK_ERROR(SQL_ERROR, loginfo, NULL, SQL_HANDLE_STMT);
  187.         }
  188.         else
  189.         {
  190.             sprintf(loginfo, "(batchCount - ignoreCount)(%d) == rowsCount(%d)", (batchCount - ignoreCount), rowsCount);
  191.             CHECK_ERROR(SQL_SUCCESS, loginfo, NULL, SQL_HANDLE_STMT);
  192.         }
  194.         // check row number returned
  195.         if (rowsCount != process)
  196.         {
  197.             sprintf(loginfo, "process(%d) != rowsCount(%d)", process, rowsCount);
  198.             CHECK_ERROR(SQL_ERROR, loginfo, NULL, SQL_HANDLE_STMT);
  199.         }
  200.         else
  201.         {
  202.             sprintf(loginfo, "process(%d) == rowsCount(%d)", process, rowsCount);
  203.             CHECK_ERROR(SQL_SUCCESS, loginfo, NULL, SQL_HANDLE_STMT);
  204.         }
  206.         for (int i = 0; i < batchCount; i++)
  207.         {
  208.             if (i < ignoreCount)
  209.             {
  210.                 if (statusptr[i] != SQL_PARAM_UNUSED)
  211.                 {
  212.                     sprintf(loginfo, "statusptr[%d](%d) != SQL_PARAM_UNUSED", i, statusptr[i]);
  213.                     CHECK_ERROR(SQL_ERROR, loginfo, NULL, SQL_HANDLE_STMT);
  214.                 }
  215.             }
  216.             else if (statusptr[i] != SQL_PARAM_SUCCESS)
  217.             {
  218.                 sprintf(loginfo, "statusptr[%d](%d) != SQL_PARAM_SUCCESS", i, statusptr[i]);
  219.                 CHECK_ERROR(SQL_ERROR, loginfo, NULL, SQL_HANDLE_STMT);
  220.             }
  221.         }
  223.         retcode = SQLFreeHandle(SQL_HANDLE_STMT, hstmtinesrt);
  224.         sprintf((char*)loginfo, "SQLFreeHandle hstmtinesrt");
  225.         CHECK_ERROR(retcode, loginfo, hstmtinesrt, SQL_HANDLE_STMT);
  226.     }
  229. exit:
  230.     printf ("\nComplete.\n");
  232.     // Connection
  233.     if (hdbc != SQL_NULL_HDBC) {
  234.         SQLDisconnect(hdbc);
  235.         SQLFreeHandle(SQL_HANDLE_DBC, hdbc);
  236.     }
  238.     // Environment
  239.     if (henv != SQL_NULL_HENV)
  240.         SQLFreeHandle(SQL_HANDLE_ENV, henv);
  242.     return 0;
  243. }