if (PQstatus(pd) == CONNECTION_OK)

// store the connection for future use

connection = pd;

//set client encoding to unicode because QString uses UTF-8 anyway

QgsDebugMsg("setting client encoding to UNICODE");

int errcode=PQsetClientEncoding(connection, "UNICODE");

if(errcode==0) {

QgsDebugMsg("encoding successfully set");

} else if(errcode==-1) {

QgsDebugMsg("error in setting encoding");

} else {

QgsDebugMsg("undefined return value from encoding setting");

}

QgsDebugMsg("Checking for select permission on the relation\n");

// Check that we can read from the table (i.e., we have

// select permission).

QString sql = "select * from " + mSchemaTableName + " limit 1";

PGresult* testAccess = PQexec(pd, (const char*)(sql.utf8()));

if (PQresultStatus(testAccess) != PGRES_TUPLES_OK)

{

showMessageBox(tr("Unable to access relation"),

tr("Unable to access the ") + mSchemaTableName +

tr(" relation.\nThe error message from the database was:\n") +

QString(PQresultErrorMessage(testAccess)) + ".\n" +

"SQL: " + sql);

PQclear(testAccess);

valid = false;

return;

}

/* Check to see if we have GEOS support and if not, warn the user about

QgsDebugMsg("Checking for GEOS support");

if(!hasGEOS(pd))

{

showMessageBox(tr("No GEOS Support!"),

tr("Your PostGIS installation has no GEOS support.\n"

"work properly.\nPlease install PostGIS with "

"GEOS support (http://geos.refractions.net)"));

}

//--std::cout << "Connection to the database was successful\n";

if (getGeometryDetails()) // gets srid and geometry type

deduceEndian();

calculateExtents();

getFeatureCount();

// Get the relation oid for use in later queries

sql = "SELECT oid FROM pg_class WHERE relname = '" + mTableName + "' AND relnamespace = ("

"SELECT oid FROM pg_namespace WHERE nspname = '" + mSchemaName + "')";

PGresult *tresult= PQexec(pd, (const char *)(sql.utf8()));

QString tableoid = PQgetvalue(tresult, 0, 0);

PQclear(tresult);

// Get the table description

sql = "SELECT description FROM pg_description WHERE "

"objoid = " + tableoid + " AND objsubid = 0";

tresult = PQexec(pd, (const char*) sql.utf8());

if (PQntuples(tresult) > 0)

mDataComment = PQgetvalue(tresult, 0, 0);

PQclear(tresult);

// Populate the field vector for this layer. The field vector contains

// field name, type, length, and precision (if numeric)

sql = "select * from " + mSchemaTableName + " limit 0";

PGresult *result = PQexec(pd, (const char *) (sql.utf8()));

//--std::cout << "Field: Name, Type, Size, Modifier:" << std::endl;

// The queries inside this loop could possibly be combined into one

// single query - this would make the code run faster.

for (int i = 0; i < PQnfields(result); i++)

{

QString fieldName = PQfname(result, i);

int fldtyp = PQftype(result, i);

QString typOid = QString().setNum(fldtyp);

int fieldModifier = PQfmod(result, i);

QString fieldComment("");

sql = "SELECT typname, typlen FROM pg_type WHERE "

"oid = (SELECT typelem FROM pg_type WHERE "

"typelem = " + typOid + " AND typlen = -1)";

PGresult* oidResult = PQexec(pd, (const char *) sql);

QString fieldTypeName = PQgetvalue(oidResult, 0, 0);

QString fieldSize = PQgetvalue(oidResult, 0, 1);

PQclear(oidResult);

sql = "SELECT attnum FROM pg_attribute WHERE "

"attrelid = " + tableoid + " AND attname = '" + fieldName + "'";

PGresult *tresult = PQexec(pd, (const char *)(sql.utf8()));

QString attnum = PQgetvalue(tresult, 0, 0);

PQclear(tresult);

sql = "SELECT description FROM pg_description WHERE "

"objoid = " + tableoid + " AND objsubid = " + attnum;

tresult = PQexec(pd, (const char*)(sql.utf8()));

if (PQntuples(tresult) > 0)

fieldComment = PQgetvalue(tresult, 0, 0);

PQclear(tresult);

QgsDebugMsg("Field: " + attnum + " maps to " + QString::number(i) + " " + fieldName + ", "

+ fieldTypeName + " (" + QString::number(fldtyp) + "), " + fieldSize + ", " + QString::number(fieldModifier));

attributeFieldsIdMap[attnum.toInt()] = i;

if(fieldName!=geometryColumn)

{

QVariant::Type fieldType;

if (fieldTypeName.find("int") != -1 || fieldTypeName.find("serial") != -1)

fieldType = QVariant::Int;

else if (fieldTypeName == "real" || fieldTypeName == "double precision" || \

fieldTypeName.find("float") != -1)

fieldType = QVariant::Double;

else

fieldType = QVariant::String;

attributeFields.insert(i, QgsField(fieldName, fieldType, fieldTypeName, fieldSize.toInt(), fieldModifier, fieldComment));

}

}

PQclear(result);

// set the primary key

getPrimaryKey();

// Set the postgresql message level so that we don't get the

// 'there is no transaction in progress' warning.

PQexec(connection, "set client_min_messages to error");

// Kick off the long running threads

QgsDebugMsg("About to touch mExtentThread");

mExtentThread.setConnInfo( mUri.connInfo );

mExtentThread.setTableName( mTableName );

mExtentThread.setSqlWhereClause( sqlWhereClause );

mExtentThread.setGeometryColumn( geometryColumn );

mExtentThread.setCallback( this );

QgsDebugMsg("About to start mExtentThread");

mExtentThread.start();

QgsDebugMsg("Main thread just dispatched mExtentThread");

QgsDebugMsg("About to touch mCountThread");

mCountThread.setConnInfo( mUri.connInfo );

mCountThread.setTableName( mTableName );

mCountThread.setSqlWhereClause( sqlWhereClause );

mCountThread.setGeometryColumn( geometryColumn );

mCountThread.setCallback( this );

QgsDebugMsg("About to start mCountThread");

mCountThread.start();

QgsDebugMsg("Main thread just dispatched mCountThread");

}

else

{

// the table is not a geometry table

numberFeatures = 0;

valid = false;

QgsDebugMsg("Invalid Postgres layer");

}

ready = false; // not ready to read yet cuz the cursor hasn't been created

} else {

valid = false;

//--std::cout << "Connection to database failed\n";

}