华为openGauss 示例

常用功能示例代码

``` // 此示例演示如何通过ODBC方式获取openGauss中的数据。 // DBtest.c (compile with: libodbc.so)

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; 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,typename,100,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_OD_err); // 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

``` /********** * 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 ***********/

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);
// Execute Statement
retcode = SQLExecute(hstmt);
sprintf((char*)loginfo, "SQLExecute stmt log: %s", (char*)sql);
CHECK_ERROR(retcode, loginfo, hstmt, SQL_HANDLE_STMT);
// Free Handle
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);
    }
    // check row number returned
    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;

} ```