更新时间:2024-02-07 GMT+08:00
分享

ODBC开发示例

常用功能示例代码

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
// 此示例演示如何通过ODBC方式获取GaussDB(DWS)中的数据。
// DBtest.c (compile with: libodbc.so)   
#include <stdlib.h> 
#include <stdio.h> 
#include <sqlext.h>
#ifdef WIN32
#include <windows.h>
#endif 
SQLHENV       V_OD_Env;        // Handle ODBC environment 
SQLHSTMT      V_OD_hstmt;      // Handle statement 
SQLHDBC       V_OD_hdbc;       // Handle connection     
char          typename[100];
SQLINTEGER    value = 100;
SQLINTEGER    V_OD_erg,V_OD_buffer,V_OD_err,V_OD_id;
SQLLEN        V_StrLen_or_IndPtr;
int main(int argc,char *argv[]) 
{         
      // 1. 申请环境句柄       
      V_OD_erg = SQLAllocHandle(SQL_HANDLE_ENV,SQL_NULL_HANDLE,&V_OD_Env);     
      if ((V_OD_erg != SQL_SUCCESS) && (V_OD_erg != SQL_SUCCESS_WITH_INFO))        
      {           
           printf("Error AllocHandle\n");           
           exit(0);        
      } 
      // 2. 设置环境属性(版本信息)         
      SQLSetEnvAttr(V_OD_Env, SQL_ATTR_ODBC_VERSION, (void*)SQL_OV_ODBC3, 0);      
      // 3. 申请连接句柄        
      V_OD_erg = SQLAllocHandle(SQL_HANDLE_DBC, V_OD_Env, &V_OD_hdbc);     
      if ((V_OD_erg != SQL_SUCCESS) && (V_OD_erg != SQL_SUCCESS_WITH_INFO))      
      {                     
           SQLFreeHandle(SQL_HANDLE_ENV, V_OD_Env);          
           exit(0);       
      }
      // 4. 设置连接属性
      SQLSetConnectAttr(V_OD_hdbc, SQL_ATTR_AUTOCOMMIT, SQL_AUTOCOMMIT_ON, 0);          
      // 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。
      // 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。    
      V_OD_erg = SQLConnect(V_OD_hdbc, (SQLCHAR*) "gaussdb", SQL_NTS,  
                           (SQLCHAR*) "userName", SQL_NTS,  (SQLCHAR*) "password", SQL_NTS);        
      if ((V_OD_erg != SQL_SUCCESS) && (V_OD_erg != SQL_SUCCESS_WITH_INFO))      
      {           
          printf("Error SQLConnect %d\n",V_OD_erg);            
          SQLFreeHandle(SQL_HANDLE_ENV, V_OD_Env);       
          exit(0);        
      }     
      printf("Connected !\n"); 
      // 6. 设置语句属性
      SQLSetStmtAttr(V_OD_hstmt,SQL_ATTR_QUERY_TIMEOUT,(SQLPOINTER *)3,0);
      // 7. 申请语句句柄
      SQLAllocHandle(SQL_HANDLE_STMT, V_OD_hdbc, &V_OD_hstmt);       
      // 8. 直接执行SQL语句。
      SQLExecDirect(V_OD_hstmt,"drop table IF EXISTS customer_t1",SQL_NTS);
      SQLExecDirect(V_OD_hstmt,"CREATE TABLE customer_t1(c_customer_sk INTEGER, c_customer_name VARCHAR(32));",SQL_NTS);
      SQLExecDirect(V_OD_hstmt,"insert into customer_t1 values(25,'li')",SQL_NTS);
      // 9. 准备执行
      SQLPrepare(V_OD_hstmt,"insert into customer_t1 values(?)",SQL_NTS); 
      // 10. 绑定参数
      SQLBindParameter(V_OD_hstmt,1,SQL_PARAM_INPUT,SQL_C_SLONG,SQL_INTEGER,0,0,
                       &value,0,NULL);
      // 11. 执行准备好的语句
      SQLExecute(V_OD_hstmt);
      SQLExecDirect(V_OD_hstmt,"select id from testtable",SQL_NTS);
      // 12. 获取结果集某一列的属性
      SQLColAttribute(V_OD_hstmt,1,SQL_DESC_TYPE_NAME,typename,sizeof(typename),NULL,NULL);                 
      printf("SQLColAtrribute %s\n",typename);
      // 13. 绑定结果集
      SQLBindCol(V_OD_hstmt,1,SQL_C_SLONG, (SQLPOINTER)&V_OD_buffer,150,
                (SQLLEN *)&V_StrLen_or_IndPtr);
      // 14. 通过SQLFetch取结果集中数据
      V_OD_erg=SQLFetch(V_OD_hstmt);
      // 15. 通过SQLGetData获取并返回数据。
      while(V_OD_erg != SQL_NO_DATA)
      {
          SQLGetData(V_OD_hstmt,1,SQL_C_SLONG,(SQLPOINTER)&V_OD_id,0,NULL);
          printf("SQLGetData ----ID = %d\n",V_OD_id);
          V_OD_erg=SQLFetch(V_OD_hstmt);
      };
      printf("Done !\n");
      // 16. 断开数据源连接并释放句柄资源
      SQLFreeHandle(SQL_HANDLE_STMT,V_OD_hstmt);    
      SQLDisconnect(V_OD_hdbc);         
      SQLFreeHandle(SQL_HANDLE_DBC,V_OD_hdbc);       
      SQLFreeHandle(SQL_HANDLE_ENV, V_OD_Env);  
      return(0);
 }

批量绑定示例代码

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
/**********************************************************************
* 请在数据源中打开UseBatchProtocol,同时指定数据库中参数support_batch_bind
* 为on
* CHECK_ERROR的作用是检查并打印错误信息。
* 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
***********************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <sql.h>
#include <sqlext.h>
#include <string.h>

#include "util.c"

void Exec(SQLHDBC hdbc, SQLCHAR* sql)
{
    SQLRETURN retcode;                  // Return status
    SQLHSTMT hstmt = SQL_NULL_HSTMT;    // Statement handle
    SQLCHAR     loginfo[2048];

    // Allocate Statement Handle
    retcode = SQLAllocHandle(SQL_HANDLE_STMT, hdbc, &hstmt);
    CHECK_ERROR(retcode, "SQLAllocHandle(SQL_HANDLE_STMT)",
                hstmt, SQL_HANDLE_STMT);

    // Prepare Statement
    retcode = SQLPrepare(hstmt, (SQLCHAR*) sql, SQL_NTS);
    sprintf((char*)loginfo, "SQLPrepare log: %s", (char*)sql);
    CHECK_ERROR(retcode, loginfo, hstmt, SQL_HANDLE_STMT);

    retcode = SQLExecute(hstmt);
    sprintf((char*)loginfo, "SQLExecute stmt log: %s", (char*)sql);
    CHECK_ERROR(retcode, loginfo, hstmt, SQL_HANDLE_STMT);

    retcode = SQLFreeHandle(SQL_HANDLE_STMT, hstmt);
    sprintf((char*)loginfo, "SQLFreeHandle stmt log: %s", (char*)sql);
    CHECK_ERROR(retcode, loginfo, hstmt, SQL_HANDLE_STMT);
}

int main () 
{
    SQLHENV  henv  = SQL_NULL_HENV;
    SQLHDBC  hdbc  = SQL_NULL_HDBC; 
    int      batchCount = 1000;
    SQLLEN   rowsCount = 0;
    int      ignoreCount = 0;

    SQLRETURN   retcode;
    SQLCHAR     dsn[1024] = {'\0'};
    SQLCHAR     loginfo[2048];

    // 交互获取数据源名称
    getStr("Please input your DSN", (char*)dsn, sizeof(dsn), 'N');
    // 交互获取批量绑定的数据量
    getInt("batchCount", &batchCount, 'N', 1);
    do 
    {
        // 交互获取批量绑定的数据中,不要入库的数据量
        getInt("ignoreCount", &ignoreCount, 'N', 1);
        if (ignoreCount > batchCount)
        {
            printf("ignoreCount(%d) should be less than batchCount(%d)\n", ignoreCount, batchCount);
        }
    }while(ignoreCount > batchCount);

    retcode = SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &henv);
    CHECK_ERROR(retcode, "SQLAllocHandle(SQL_HANDLE_ENV)",
                henv, SQL_HANDLE_ENV);

    // Set ODBC Verion
    retcode = SQLSetEnvAttr(henv, SQL_ATTR_ODBC_VERSION,
                                        (SQLPOINTER*)SQL_OV_ODBC3, 0);
    CHECK_ERROR(retcode, "SQLSetEnvAttr(SQL_ATTR_ODBC_VERSION)",
                henv, SQL_HANDLE_ENV);

    // Allocate Connection
    retcode = SQLAllocHandle(SQL_HANDLE_DBC, henv, &hdbc);
    CHECK_ERROR(retcode, "SQLAllocHandle(SQL_HANDLE_DBC)",
                henv, SQL_HANDLE_DBC);

    // Set Login Timeout
    retcode = SQLSetConnectAttr(hdbc, SQL_LOGIN_TIMEOUT, (SQLPOINTER)5, 0);
    CHECK_ERROR(retcode, "SQLSetConnectAttr(SQL_LOGIN_TIMEOUT)",
                hdbc, SQL_HANDLE_DBC);

    // Set Auto Commit
    retcode = SQLSetConnectAttr(hdbc, SQL_ATTR_AUTOCOMMIT,
                                        (SQLPOINTER)(1), 0);
    CHECK_ERROR(retcode, "SQLSetConnectAttr(SQL_ATTR_AUTOCOMMIT)",
                hdbc, SQL_HANDLE_DBC);

    // Connect to DSN
    sprintf(loginfo, "SQLConnect(DSN:%s)", dsn);
    retcode = SQLConnect(hdbc, (SQLCHAR*) dsn, SQL_NTS,
                               (SQLCHAR*) NULL, 0, NULL, 0);
    CHECK_ERROR(retcode, loginfo, hdbc, SQL_HANDLE_DBC);

    // init table info.
    Exec(hdbc, "drop table if exists test_odbc_batch_insert");
    Exec(hdbc, "create table test_odbc_batch_insert(id int primary key, col varchar2(50))");

    // 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:
    {
        SQLRETURN retcode; 
        SQLHSTMT hstmtinesrt = SQL_NULL_HSTMT;
        int          i;
        SQLCHAR      *sql = NULL;
        SQLINTEGER   *ids  = NULL;
        SQLCHAR      *cols = NULL;
        SQLLEN       *bufLenIds = NULL;
        SQLLEN       *bufLenCols = NULL;
        SQLUSMALLINT *operptr = NULL;
        SQLUSMALLINT *statusptr = NULL;
        SQLULEN      process = 0;

        // 这里是按列构造,每个字段的内存连续存放在一起。
        ids = (SQLINTEGER*)malloc(sizeof(ids[0]) * batchCount);
        cols = (SQLCHAR*)malloc(sizeof(cols[0]) * batchCount * 50);
        // 这里是每个字段中,每一行数据的内存长度。
        bufLenIds = (SQLLEN*)malloc(sizeof(bufLenIds[0]) * batchCount);
        bufLenCols = (SQLLEN*)malloc(sizeof(bufLenCols[0]) * batchCount);
        // 该行是否需要被处理,SQL_PARAM_IGNORE 或 SQL_PARAM_PROCEED
        operptr = (SQLUSMALLINT*)malloc(sizeof(operptr[0]) * batchCount);
        memset(operptr, 0, sizeof(operptr[0]) * batchCount);
        // 该行的处理结果。
        // 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。
        statusptr = (SQLUSMALLINT*)malloc(sizeof(statusptr[0]) * batchCount);
        memset(statusptr, 88, sizeof(statusptr[0]) * batchCount);

        if (NULL == ids || NULL == cols || NULL == bufLenCols || NULL == bufLenIds)
        {
            fprintf(stderr, "FAILED:\tmalloc data memory failed\n");
            goto exit;
        }

        for (int i = 0; i < batchCount; i++)
        {
            ids[i] = i;
            sprintf(cols + 50 * i, "column test value %d", i);
            bufLenIds[i] = sizeof(ids[i]);
            bufLenCols[i] = strlen(cols + 50 * i);
            operptr[i] = (i < ignoreCount) ? SQL_PARAM_IGNORE : SQL_PARAM_PROCEED;
        }

        // Allocate Statement Handle
        retcode = SQLAllocHandle(SQL_HANDLE_STMT, hdbc, &hstmtinesrt);
        CHECK_ERROR(retcode, "SQLAllocHandle(SQL_HANDLE_STMT)",
                    hstmtinesrt, SQL_HANDLE_STMT);

        // Prepare Statement
        sql = (SQLCHAR*)"insert into test_odbc_batch_insert values(?, ?)";
        retcode = SQLPrepare(hstmtinesrt, (SQLCHAR*) sql, SQL_NTS);
        sprintf((char*)loginfo, "SQLPrepare log: %s", (char*)sql);
        CHECK_ERROR(retcode, loginfo, hstmtinesrt, SQL_HANDLE_STMT);

        retcode = SQLSetStmtAttr(hstmtinesrt, SQL_ATTR_PARAMSET_SIZE, (SQLPOINTER)batchCount, sizeof(batchCount));
        CHECK_ERROR(retcode, "SQLSetStmtAttr", hstmtinesrt, SQL_HANDLE_STMT);

        retcode = SQLBindParameter(hstmtinesrt, 1, SQL_PARAM_INPUT, SQL_C_SLONG, SQL_INTEGER, sizeof(ids[0]), 0,&(ids[0]), 0, bufLenIds);
        CHECK_ERROR(retcode, "SQLBindParameter for id", hstmtinesrt, SQL_HANDLE_STMT);

        retcode = SQLBindParameter(hstmtinesrt, 2, SQL_PARAM_INPUT, SQL_C_CHAR, SQL_CHAR, 50, 50, cols, 50, bufLenCols);
        CHECK_ERROR(retcode, "SQLBindParameter for cols", hstmtinesrt, SQL_HANDLE_STMT);

        retcode = SQLSetStmtAttr(hstmtinesrt, SQL_ATTR_PARAMS_PROCESSED_PTR, (SQLPOINTER)&process, sizeof(process));
        CHECK_ERROR(retcode, "SQLSetStmtAttr for SQL_ATTR_PARAMS_PROCESSED_PTR", hstmtinesrt, SQL_HANDLE_STMT);

        retcode = SQLSetStmtAttr(hstmtinesrt, SQL_ATTR_PARAM_STATUS_PTR, (SQLPOINTER)statusptr, sizeof(statusptr[0]) * batchCount);
        CHECK_ERROR(retcode, "SQLSetStmtAttr for SQL_ATTR_PARAM_STATUS_PTR", hstmtinesrt, SQL_HANDLE_STMT);

        retcode = SQLSetStmtAttr(hstmtinesrt, SQL_ATTR_PARAM_OPERATION_PTR, (SQLPOINTER)operptr, sizeof(operptr[0]) * batchCount);
        CHECK_ERROR(retcode, "SQLSetStmtAttr for SQL_ATTR_PARAM_OPERATION_PTR", hstmtinesrt, SQL_HANDLE_STMT);

        retcode = SQLExecute(hstmtinesrt);
        sprintf((char*)loginfo, "SQLExecute stmt log: %s", (char*)sql);
        CHECK_ERROR(retcode, loginfo, hstmtinesrt, SQL_HANDLE_STMT);

        retcode = SQLRowCount(hstmtinesrt, &rowsCount);
        CHECK_ERROR(retcode, "SQLRowCount execution", hstmtinesrt, SQL_HANDLE_STMT);

        if (rowsCount != (batchCount - ignoreCount))
        {
            sprintf(loginfo, "(batchCount - ignoreCount)(%d) != rowsCount(%d)", (batchCount - ignoreCount), rowsCount);
            CHECK_ERROR(SQL_ERROR, loginfo, NULL, SQL_HANDLE_STMT);
        }
        else
        {
            sprintf(loginfo, "(batchCount - ignoreCount)(%d) == rowsCount(%d)", (batchCount - ignoreCount), rowsCount);
            CHECK_ERROR(SQL_SUCCESS, loginfo, NULL, SQL_HANDLE_STMT);
        }

        if (rowsCount != process)
        {
            sprintf(loginfo, "process(%d) != rowsCount(%d)", process, rowsCount);
            CHECK_ERROR(SQL_ERROR, loginfo, NULL, SQL_HANDLE_STMT);
        }
        else
        {
            sprintf(loginfo, "process(%d) == rowsCount(%d)", process, rowsCount);
            CHECK_ERROR(SQL_SUCCESS, loginfo, NULL, SQL_HANDLE_STMT);
        }

        for (int i = 0; i < batchCount; i++)
        {
            if (i < ignoreCount)
            {
                if (statusptr[i] != SQL_PARAM_UNUSED)
                {
                    sprintf(loginfo, "statusptr[%d](%d) != SQL_PARAM_UNUSED", i, statusptr[i]);
                    CHECK_ERROR(SQL_ERROR, loginfo, NULL, SQL_HANDLE_STMT);
                }
            }
            else if (statusptr[i] != SQL_PARAM_SUCCESS)
            {
                sprintf(loginfo, "statusptr[%d](%d) != SQL_PARAM_SUCCESS", i, statusptr[i]);
                CHECK_ERROR(SQL_ERROR, loginfo, NULL, SQL_HANDLE_STMT);
            }
        }

        retcode = SQLFreeHandle(SQL_HANDLE_STMT, hstmtinesrt);
        sprintf((char*)loginfo, "SQLFreeHandle hstmtinesrt");
        CHECK_ERROR(retcode, loginfo, hstmtinesrt, SQL_HANDLE_STMT);
    }


exit:
    printf ("\nComplete.\n");

    // Connection
    if (hdbc != SQL_NULL_HDBC) {
        SQLDisconnect(hdbc);
        SQLFreeHandle(SQL_HANDLE_DBC, hdbc);
    }

    // Environment
    if (henv != SQL_NULL_HENV)
        SQLFreeHandle(SQL_HANDLE_ENV, henv);

    return 0;
}
分享:

    相关文档

    相关产品