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How to access the database from MQL4 , ORACL , MSSQL, MySQL - page 8

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sergeev >>:

А что вы конкретно имеете в наработке по данному вопросу MS SQL?

приведите код и покажите где у вас не работает. будем разбираться.

//TheVilkas example

#include <ADOLib.mqh>

int createCnn=0;
int openCnn=0;
int Insert=0;


string StringConnection="DSN=dbForex;UID=sa;PWD=;";



int init()
{



CloseConnection();
DestroyConnection();

int createCnn=CreateConnection();
Sleep(10);

int openCnn=OpenConnection(StringConnection,adUseClient,0);
Sleep(10);


return(0);
}



//job example:

int start()
{
//this is just in case a connection is closed or "gone bad" - there are enough reasons
if (createCnn<=0 || IsOpenConnection()==0)
{
createCnn=0;
openCnn=0;

CloseConnection();
Sleep(10);

DestroyConnection();
Sleep(10);

createCnn=CreateConnection();
Sleep(30);
}

if (createCnn>0 &&(openCnn<=0 || IsOpenConnection()==0 || Insert==0))
{
openCnn=0;

CloseConnection();
Sleep(10);

openCnn=OpenConnection(StringConnection,adUseClient,0);
Sleep(30);
}



//and then write ticks into the database

string Company=AccountCompany();
string Symb=Symbol();

//insertion code works
/*
string CommandText="INSERT INTO Rates (TimeCurrent,AccountCompany,Symb,DateTimeRate,Ask,Bid) "+
"VALUES("+TimeCurrent()+",'"+Company+"','"+Symb+"','"+DateTimeRate+"',"+Ask+","+Bid+")";
Execute(CommandText,adAsyncFetch);
Sleep(15);
*/
//I want to receive data from the database

string CommandText="select ask from test where ask='1.4560'";
string text=Execute(CommandText,adAsyncFetch);
Comment(text);

Sleep(15);

//returns 1;
}



//+------------------------------------------------------------------+
//| expert deinitialization function |
//+------------------------------------------------------------------+
int deinit()
{
CloseConnection();
DestroyConnection();

return(0);
}

sergeev >>:

А что вы конкретно имеете в наработке по данному вопросу MS SQL?

приведите код и покажите где у вас не работает. будем разбираться.


//Sample Graff.

//+------------------------------------------------------------------+
//| news001.mq4 |
//| Copyright © 2009, Graff |
//| |
//+------------------------------------------------------------------+
#property copyright "Copyright © 2009, Graff"
#property link ""

#property indicator_chart_window

#define DELIM ";"
//#include <mysql.mqh>

#import "libmysql.dll"
int mysql_init(int db);
int mysql_errno(int TMYSQL);
int mysql_real_connect( int TMYSQL,string host,string user,string password, string DB,int port,int socket,int clientflag);
int mysql_real_query(int TMSQL,string query,int length);
void mysql_close(int TMSQL);

int mysql_store_result(int TMSQL);
string mysql_fetch_row(int result);
int mysql_num_rows(int result);
void mysql_free_result(int result);

//#import

int mysql;

int mTicket, mType;
string mSymbol;
double mLots, mOpen, mClose, mStopLoss, mTakeProfit;

//+------------------------------------------------------------------+
//| Custom indicator initialization function |
//+------------------------------------------------------------------+
int init()
{
//---- indicators
string row;
connect();
string query="Select ask from calendar WHERE ask = '1.4567'";
int length=StringLen(query);
mysql_real_query(mysql,query,length);
int result = mysql_store_result(mysql);
int numOfRows = mysql_num_rows(result);
for (int i=0;i<numOfRows;i++) {
row = mysql_fetch_row(result);
Print(row);

Comment(row);

//returns a normal value but at the beginning of the load

IMHO - you need to write your own dll. Too many language constructs are missing in MQL4 - MQL5 promises more.

IMHO is not helpful here.

What about the documentation. What does Execute return?

I think it returns a boolean value. Your text says 1. It means that it was executed correctly.

You have to search through the recordings.

Here' s a demonstration of how to work through ADO - might come in handy - quick and easy to do

I have an excellent connection between MT4 and MYSQL. No other libraries except libmySQL.dll are used.
Please tell me, who knows, is it possible to integrate MetaTrader 5 with Oracle DBS?
Twilight >>:


А как осуществить чтение из БД?

ADOLib.mqh looks like this:


// Constants for enum CursorTypeEnum

#define adOpenUnspecified 4294967295 //$FFFFFFFFFF;
#define adOpenForwardOnly 0 //$000000000000;
#define adOpenKeyset 1 //$00000001;
#define adOpenDynamic 2 //$00000002;
#define adOpenStatic 3 //$00000003;

// Constants for enum LockTypeEnum

#define adLockUnspecified 4294967295 //$FFFFFFFFFF;
#define adLockReadOnly 1 //$00000001
#define adLockPessimistic 2 //$00000002;
#define adLockOptimistic 3 //$$00000003;
#define adLockBatchOptimistic 4 //$00000004;

// Constants for enum ExecuteOptionEnum

#define adOptionUnspecified 4294967295 //$FFFFFFFFFF;
#define adAsyncExecute 16 //$00000010;
#define adAsyncFetch 32 //$00000020;
#define adAsyncFetchNonBlocking 64 //$00000040;
#define adExecuteNoRecords 128 //$00000080;
#define adExecuteStream 296 //$00000400;
#define adExecuteRecord 2048 //$00000800;

// Constants for enum CursorLocationEnum

#define adUseNone 1 //$00000001;
#define adUseServer 2 //$00000002;
#define adUseClient 3 //$00000003;
#define adUseClientBatch 3 //$00000003;

// Constants for enum CommandTypeEnum

#define adCmdUnspecified 4294967295 //$FFFFFFFFFF;
#define adCmdUnknown 8 //$00000008;
#define adCmdText 1 //$00000001;
#define adCmdTable 2 //$00000002;
#define adCmdStoredProc 4 //$00000004;
#define adCmdFile 256 //$00000100;
#define adCmdTableDirect 512 //$00000200;

#import "ADOLib.dll".
int CreateConnection();
int DestroyConnection();
int OpenConnection(string ConnectionString,int CursorLocation,int CommandTimeout);
int CloseConnection();
int IsOpenConnection();
int Execute(string CommandText,int ExecuteOption);
int BeginTrans();
int CommitTrans();
int RollbackTrans();
int OpenTable(string Qry,int CursorLocation,int CursorType,int LockType,int Options);
int CloseTable();
int Requery();
int Update();
int UpdateBatch();
int Cancel();
int CancelBatch();
int CancelUpdate();
int Find(string Criteria,int SearchDirection,int Start);
int Filter(string Criteria);
int BOF();
int EOF();
int MoveFirst();
int MoveLast();
int MoveNext();
string TableStatus();
int FieldsCount();
string FieldName(int I);
string FieldType(int Name);
string FieldTypeByPos(int I);
string GetFieldValue(string Name);
string GetFieldValueByPos(int I);
int SetFieldValue(string Name);

intFieldValueByPos(int I);


in ADOLib.mqh

there are methods:

GetFieldValue

GetFieldValueByPos


after successful opening of the table "SELECT * FROM NameTable"

set to the right record with

int is_succ=MoveFirst();

and if successful, read:

string FieldVal=";

if(is_succ=1)

FieldVal=GetFieldValue("NameField");

or read by the numeric handler of the field:

int hbdFld=0;

if(is_succ=1)

FieldVal=GetFieldValueByPos(hndFld);

the MoveFirst() method which sets to the FIRST entry,

the ones you want are either overridden by MoveNext(),

and the ones you don't want are either searched and/or filtered.

see. Find(),Filter() or WHERE in SELECT....

and also the GetFieldValueXXXX data reading methods convert field values to

string type, so if necessary the

to the required type

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