C++11 使用ODBC连接snowflake数据库

折腾了两天才通。之前看Snowflake官方的文档说只支持到MacOS 10.15。后来猜想应该是文档没更新。后来用MacOS BigSur折腾了一下,发现真的可以,后面会封装一个连接类来处理数据库请求。以便好在本地做少量的数据测试。
这里只是一个demo。验证连接和取数据而已。

步骤:
1、配置ODBC数据源。文档如下。
https://docs.snowflake.com/en/user-guide/odbc-mac.html
2、写代码进行测试。
程序目录如下,

image.png

CMakeLists.txt
注意程序不需要链接libSnowflake.dylib动态库,这个是snowflake的驱动。ODBC连接时会自动加载。


cmake_minimum_required(VERSION 2.6)
project(ref_demo2_test)

add_definitions(-std=c++14)
add_definitions(-g)



find_package(Boost REQUIRED COMPONENTS
    system
    filesystem
    serialization
    program_options
    thread
    )

include_directories(${Boost_INCLUDE_DIRS} /usr/local/include /usr/local/iODBC/include /opt/snowflake/snowflakeodbc/include/ ${CMAKE_CURRENT_SOURCE_DIR}/../../)

LINK_DIRECTORIES(/usr/local/lib /usr/local/iODBC/lib /opt/snowflake/snowflakeodbc/lib/universal)

file( GLOB APP_SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/*.cpp ${CMAKE_CURRENT_SOURCE_DIR}/*.h
    ${CMAKE_CURRENT_SOURCE_DIR}/../impl/*.cpp ${CMAKE_CURRENT_SOURCE_DIR}/*.cpp)
foreach( sourcefile ${APP_SOURCES} )
        file(RELATIVE_PATH filename ${CMAKE_CURRENT_SOURCE_DIR} ${sourcefile})
    
        string(FIND "${filename}"  "test.cpp" "TEMP")
    if( NOT "${TEMP}" STREQUAL "-1" )
        string(REPLACE ".cpp" "" file ${filename})
        add_executable(${file}  ${APP_SOURCES})
        target_link_libraries(${file} ${Boost_LIBRARIES})
        target_link_libraries(${file}  ssl crypto libgtest.a libgtest_main.a libgmock.a iodbc iodbcinst pthread)
    endif()
endforeach( sourcefile ${APP_SOURCES})

sf_db.h

#ifndef _FREDRIC_SF_DB_H_
#define _FREDRIC_SF_DB_H_

#include "sf_odbc.h"
#include "sql.h"
#include "sqlext.h"

#include 
#include 


struct Event {
    std::string changed_time;
    std::string event_type_name;
    std::string change_column;
    std::string old_value;
    std::string new_value;
    std::string meta;
};

/**
 * iodbc
 * /usr/local/iODBC/include
 * /usr/local/iODBC/lib
 * */

std::vector singleQuery();

#endif

sf_db.cpp

#include "sf_db/sf_db.h"

#include 

std::vector singleQuery() {

    std::vector events;
    SQLHENV henv;
    SQLHDBC hdbc;
    SQLHSTMT hstmt;
    SQLRETURN retcode;

    SQLCHAR *OutConnStr = (SQLCHAR *)malloc(255);
    SQLSMALLINT *OutConnStrLen = (SQLSMALLINT *)malloc(255);

    SQLCHAR changed_time[100];
    SQLCHAR event_type_name[100];
    SQLCHAR change_column[100];
    SQLCHAR old_value[2000];
    SQLCHAR new_value[2000];
    SQLCHAR meta[1000];

    SQLLEN change_time_len = 0, event_type_len = 0, change_column_len = 0,
           old_value_len = 0, new_value_len = 0, meta_len = 0;

    // Allocate environment handle
    retcode = SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &henv);

    // Set the ODBC version environment attribute
    if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {
        retcode =
            SQLSetEnvAttr(henv, SQL_ATTR_ODBC_VERSION, (void *)SQL_OV_ODBC3, 0);

        // Allocate connection handle
        if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {
            retcode = SQLAllocHandle(SQL_HANDLE_DBC, henv, &hdbc);

            // Set login timeout to 5 seconds
            if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {
                SQLSetConnectAttr(hdbc, SQL_LOGIN_TIMEOUT, (SQLPOINTER)5, 0);

                // Connect to data source
                retcode = SQLConnect(hdbc, (SQLCHAR *)"product_odbc", SQL_NTS,
                                     (SQLCHAR *)NULL, 0,
                                     (SQLCHAR *)"{SQLPASSWORD}", SQL_NTS);

                // Allocate statement handle
                if (retcode == SQL_SUCCESS ||
                    retcode == SQL_SUCCESS_WITH_INFO) {
                    retcode = SQLAllocHandle(SQL_HANDLE_STMT, hdbc, &hstmt);
                    // Process data
                    if (retcode == SQL_SUCCESS ||
                        retcode == SQL_SUCCESS_WITH_INFO) {
                        std::cout << "connect to product_odbc success!"
                                  << std::endl;
                        auto rc = SQLExecDirect(hstmt,
                     (SQLCHAR *) "select  change_time,EVENT_TYPE_NAME, change_column, old_value, new_value,meta from AA_INTELLIGENCE_PRODUCTION.ADL_MASTER.dim_event_service_v1 where  event_type_name='screenshot_change' and product_key=20600000009072 order by change_time desc limit 10;", SQL_NTS);

                        if (retcode == SQL_SUCCESS ||
                            retcode == SQL_SUCCESS_WITH_INFO) {
                            retcode =
                                SQLBindCol(hstmt, 1, SQL_C_CHAR, &changed_time,
                                           100, &change_time_len);
                            retcode = SQLBindCol(hstmt, 2, SQL_C_CHAR,
                                                 &event_type_name, 100,
                                                 &event_type_len);
                            retcode =
                                SQLBindCol(hstmt, 3, SQL_C_CHAR, &change_column,
                                           100, &change_column_len);
                            retcode =
                                SQLBindCol(hstmt, 4, SQL_C_CHAR, &old_value,
                                           2000, &old_value_len);
                            retcode =
                                SQLBindCol(hstmt, 5, SQL_C_CHAR, &new_value,
                                           2000, &new_value_len);
                            retcode = SQLBindCol(hstmt, 6, SQL_C_CHAR, &meta,
                                                 1000, &meta_len);

                            // Fetch and print each row of data until
                            // SQL_NO_DATA returned.
                            for (int i = 0;; i++) {
                                retcode = SQLFetch(hstmt);
                                if (retcode == SQL_SUCCESS ||
                                    retcode == SQL_SUCCESS_WITH_INFO) {
                                    std::string s_change_time(
                                        (const char *)changed_time,
                                        change_time_len);
                                    std::string s_event_type(
                                        (const char *)event_type_name,
                                        event_type_len);
                                    std::string s_change_column(
                                        (const char *)change_column,
                                        change_column_len);
                                    std::string s_old_value(
                                        (const char *)old_value, old_value_len);
                                    std::string s_new_value(
                                        (const char *)new_value, new_value_len);
                                    std::string s_meta((const char *)meta,
                                                       meta_len);

                                    std::cout << i + 1 << " " << s_change_time
                                              << " " << s_event_type << " "
                                              << s_change_column << " "
                                              << s_old_value << " "
                                              << s_new_value << " " << s_meta
                                              << std::endl;
                                    Event event {s_change_time, s_event_type,
                                        s_change_column, s_old_value, s_new_value,
                                        s_meta};
                                    events.emplace_back(std::move(event));
                                    
                                } else {
                                    if (retcode != SQL_NO_DATA) {
                                        std::cout
                                            << "SQLFetch Error, error code: "
                                            << retcode << std::endl;
                                        break;
                                    } else {
                                        break;
                                    }
                                }
                            }
                        }
                        SQLFreeHandle(SQL_HANDLE_STMT, hstmt);
                    }

                    SQLDisconnect(hdbc);
                } else {
                    std::cout << "Error Connected!" << retcode << std::endl;
                    std::cout << "connect to test_odbc1 failed!" << std::endl;
                }

                SQLFreeHandle(SQL_HANDLE_DBC, hdbc);
            }
        }
        SQLFreeHandle(SQL_HANDLE_ENV, henv);
    }

    return std::move(events);
}

sf_db_test.cpp

#include "sf_db/sf_db.h"

#include 

GTEST_TEST(SFDBTests, TestSingleQuery) {
    auto results = singleQuery();
    ASSERT_EQ(10, results.size());
}

程序输出如下,


image.png

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