PostgreSQL Client

A complete PostgreSQL client implemented in pure MQL5 over native MetaTrader 5 TCP sockets.

The library implements the PostgreSQL client with MD5 and SCRAM-SHA-256 authentication, SSL/TLS, the Simple Query Protocol, and explicit transactions.

No DLLs, no external dependencies, no third-party services.

Features

Getting Started

Pass useSSL = true to Pg_Connect. The library performs the standard PostgreSQL SSLRequest negotiation and upgrades to TLS via SocketTlsHandshake. If the server rejects the request the client logs a warning and continues unencrypted.

Run any SQL statement —  INSERT ,  UPDATE ,  DELETE , DDL — through a single Pg_Query call. Each call returns a result handle whose lifecycle is managed by the client: the previous result on the same client is freed automatically when the next query runs.

Pg_Begin ,  Pg_Commit , and Pg_Rollback provide one-call wrappers around the standard SQL transaction commands. For nested error recovery use savepoints ( SAVEPOINT name  /  ROLLBACK TO name ) via Pg_Query.

#include <PostgresLib.mqh>

void OnStart()
{
   long h = Pg_Create();
   Pg_Connect(h, "127.0.0.1", 5432, "postgres", "postgres", "postgres", false, "MQLPgClient");

   long r = Pg_Query(h, "SELECT symbol, price, timestamp FROM trades LIMIT 10");
   while(Res_Next(r))
      Print(Res_GetValueByName(r, "symbol"), " @ ", Res_GetDouble(r, Res_FieldIndex("price")), " at ", Res_GetValue(r, 2));

   Pg_Disconnect(h);
   Pg_Destroy(h);
}