WideStudio/MWT Programming Guide	WideStudio/MWT Index Table of contents

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利用数据库Class的数据库访问

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通过ODBC进行数据库访问

可以利用WSCvdb Class，通过ODBC接口进行数据库访问。

使用ODBC访问时，属性 WSNtype 指定为 WS_DB_ODBC，在WSCvdb::open 函数中指定DSN 、用户注册名，密码进行实行。

#include <WScom.h>
#include <WSCfunctionList.h>
#include <WSCbase.h>
//----------------------------------------------------------
//Function for the event procedure
//----------------------------------------------------------
#include <WSCvdb.h>
extern WSCvdb* newvdb__000;

void db_ep(WSCbase* object){
  long ret = newvdb__000->open("dn","user","passwd");
  if (ret == WS_NO_ERR){
    //Connecting
  }else{
    //Connection failed with getting an error message.
    char buffer[1024];
    newvdb__000->getErrorMsg(buffer,1024);
  }
}

通过ODBC进行访问时，在WSNhostname中设定DSN,在WSNusername中设定用户名，在WSNpassword中设定密码，不带参数实行WSCvdb::open函数。

#include <WScom.h>
#include <WSCfunctionList.h>
#include <WSCbase.h>
//----------------------------------------------------------
//Function for the event procedure
//----------------------------------------------------------
#include <WSCvdb.h>
extern WSCvdb* newvdb__000;

void db_ep(WSCbase* object){
  long ret = newvdb__000->open();
  if (ret == WS_NO_ERR){
    //Connecting.
  }else{
    //Connection failure with getting an error message.
    char buffer[1024];
    newvdb__000->getErrorMsg(buffer,1024);
  }
}

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进行PostgreSQL接口的数据库访问

通过利用WSCvdb Class，可以通过 PostgreSQL 接口直接PostgreSQL 数据库访问。

使用PostgreSQL 接口进行访问时，属性WSNtype 指定为 WS_DB_POSTGRES ，在WSCvdb::open 函数中指定主机名，用户注册名，密码，数据库名，端口号码进行实行。

#include <WScom.h>
#include <WSCfunctionList.h>
#include <WSCbase.h>
//----------------------------------------------------------
//Function for the event procedure
//----------------------------------------------------------
#include <WSCvdb.h>
extern WSCvdb* newvdb__000;

void db_ep(WSCbase* object){
  long ret = newvdb__000->open("dn","user","passwd","dbname","5432");
  if (ret == WS_NO_ERR){
    //Connecting.
  }else{
    //Connection failure with getting an error message.
    char buffer[1024];
    newvdb__000->getErrorMsg(buffer,1024);
  }
}

通过PostgreSQL进行访问时，在WSNhostname中设定主机名,在WSNusername中设定用户名，在WSNpassword中设定密码，WSNdbname中设定数据库名，在WSNport中指定端口号码，不带参数实行WSCvdb::open函数。

#include <WScom.h>
#include <WSCfunctionList.h>
#include <WSCbase.h>
//----------------------------------------------------------
//Function for the event procedure
//----------------------------------------------------------
#include <WSCvdb.h>
extern WSCvdb* newvdb__000;

void db_ep(WSCbase* object){
  long ret = newvdb__000->open();
  if (ret == WS_NO_ERR){
    //Connecting.
  }else{
    //Connection failure with getting an error message.
    char buffer[1024];
    newvdb__000->getErrorMsg(buffer,1024);
  }
}

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表数据的作成

实行WSCvdb::open 对数据库连接成功后，能发行SQL来操作数据库。下面的例子中，是数据库上制作一个shinamono 表数据的例子。

#include <WScom.h>
#include <WSCfunctionList.h>
#include <WSCbase.h>
//----------------------------------------------------------
//Function for the event procedure
//----------------------------------------------------------
#include <WSCvdb.h>
extern WSCvdb* newvdb__000;

void db_ep(WSCbase* object){
  char buf1[512];
  strcpy(buf1,
         "create table shinamono(code int, hinmei char(20), nedan float)");
  newvdb__000->sqlExecute(buf1);

  if (ret == WS_NO_ERR){
    //Success
  }else{
    //Connection failure with getting an error message
    char buffer[1024];
    newvdb__000->getErrorMsg(buffer,1024);
  }
}

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表数据中追加数据

实行WSCvdb::open 对数据库的连接成功后，如果有可以操作的表数据，则可发行SQL将数据追加到表数据。下面的例子，是在数据库上名为shinamono的表数据里追加数据的例子。

#include <WScom.h>
#include <WSCfunctionList.h>
#include <WSCbase.h>
//----------------------------------------------------------
//Function for the event procedure
//----------------------------------------------------------
#include <WSCvdb.h>
extern WSCvdb* newvdb__000;

void db_ep(WSCbase* object){
  newvdb__000->beginTran();
  strcpy(buf1, "insert into shinamono values(1, 'Orange', 100)");
  newvdb__000->sqlExecute(buf1);
  strcpy(buf1, "insert into shinamono values(2, 'Apple', 200)");
  newvdb__000->sqlExecute(buf1);
  strcpy(buf1, "insert into shinamono values(3, 'Banana', 300)");
  newvdb__000->sqlExecute(buf1);
  strcpy(buf1, "insert into shinamono values(4, 'Melon', 0)");
  newvdb__000->sqlExecute(buf1);

  newvdb__000->commitTran();

}

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参照表数据上的数据

实行WSCvdb::open 对数据库的连接成功后，如果存在可以参照的表数据，则可发行SQL来参照表数据上的数据。下面的例子，是从数据库上名为 shinamono 的表数据中参照数据，并且更新数据。

#include <WScom.h>
#include <WSCfunctionList.h>
#include <WSCbase.h>
//----------------------------------------------------------
//Function for the event procedure
//----------------------------------------------------------
#include <WSCvdb.h>
#include <WSCdb.h>
extern WSCvdb* newvdb__000;

void db_ep(WSCbase* object){
  WSCvariant var;
  WSCstring outp;
  newvdb__000->beginTran();
  WSCdbRecord rs(newvdb__000);
  if(rs.open("select * from shinamono order by code") == WS_NO_ERR) {
    while (!rs.isEOF()) {
      outp = "";
      rs.getColValue("code", &var);
      int code = (int)var;
      outp << "code:" << (int)var << " ";
      rs.getColValue("hinmei", &var);
      outp << "hinmei:" << (char*)var << " ";
      rs.getColValue("nedan", &var);
      char buf[80];
      char buf1[80];
      double nedan = (float)var + 10;

      sprintf(buf, "%f", (float)var);
      outp << "nedan:" << buf << "\n";
      printf((char*)outp);

      if(nedan != 0) {
        sprintf(buf1, "update shinamono set nedan = %f where code = %d",
                nedan, code);
      } else {
        sprintf(buf1, "delete from shinamono where code = %d", code);
      }
      newvdb__000->sqlExecute(buf1);
      rs.moveNext();
    }
  }
  rs.close();
  newvdb__000->commitTran();
}