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qgspostgresprovider.cpp
2840 lines (2407 loc) · 85.6 KB
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qgspostgresprovider.cpp
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/***************************************************************************
qgspostgresprovider.cpp - QGIS data provider for PostgreSQL/PostGIS layers
-------------------
begin : 2004/01/07
copyright : (C) 2004 by Gary E.Sherman
email : sherman at mrcc.com
***************************************************************************/
/***************************************************************************
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
***************************************************************************/
/* $Id$ */
#include <fstream>
#include <iostream>
#include <cassert>
#include <QStringList>
#include <QApplication>
#include <QMessageBox>
#include <QEvent>
#include <QCustomEvent>
#include <QTextOStream>
// for ntohl
#ifdef WIN32
#include <winsock.h>
#else
#include <netinet/in.h>
#endif
#include <qgis.h>
#include <qgsfeature.h>
#include <qgsfield.h>
#include <qgsrect.h>
#include <qgsmessageviewer.h>
#include "qgsprovidercountcalcevent.h"
#include "qgsproviderextentcalcevent.h"
#include "qgspostgresprovider.h"
#include "qgspostgrescountthread.h"
#include "qgspostgresextentthread.h"
#include "qgspostgisbox3d.h"
#include "qgslogger.h"
#ifdef WIN32
#define QGISEXTERN extern "C" __declspec( dllexport )
#else
#define QGISEXTERN extern "C"
#endif
const QString POSTGRES_KEY = "postgres";
const QString POSTGRES_DESCRIPTION = "PostgreSQL/PostGIS data provider";
QgsPostgresProvider::QgsPostgresProvider(QString const & uri)
: QgsVectorDataProvider(uri),
geomType(QGis::WKBUnknown),
gotPostgisVersion(FALSE)
{
// assume this is a valid layer until we determine otherwise
valid = true;
/* OPEN LOG FILE */
// Make connection to the data source
// For postgres, the connection information is passed as a space delimited
// string:
// host=192.168.1.5 dbname=test port=5342 user=gsherman password=xxx table=tablename
// Strip the table and sql statement name off and store them
int sqlStart = uri.find(" sql");
int tableStart = uri.find("table=");
#ifdef QGISDEBUG
qDebug( "****************************************");
qDebug( "**** Postgresql Layer Creation *****" );
qDebug( "****************************************");
qDebug( (const char*)(QString("URI: ") + uri).toLocal8Bit().data() );
QString msg;
qDebug( "tableStart: " + msg.setNum(tableStart) );
qDebug( "sqlStart: " + msg.setNum(sqlStart));
#endif
mTableName = uri.mid(tableStart + 6, sqlStart - tableStart -6);
if(sqlStart > -1)
{
sqlWhereClause = uri.mid(sqlStart + 5);
}
else
{
sqlWhereClause = QString::null;
}
QString connInfo = uri.left(uri.find("table="));
#ifdef QGISDEBUG
qDebug( (const char*)(QString("Table name is ") + mTableName).toLocal8Bit().data());
qDebug( (const char*)(QString("SQL is ") + sqlWhereClause).toLocal8Bit().data() );
qDebug( "Connection info is " + connInfo);
#endif
// calculate the schema if specified
mSchemaName = "";
if (mTableName.find(".") > -1) {
mSchemaName = mTableName.left(mTableName.find("."));
}
geometryColumn = mTableName.mid(mTableName.find(" (") + 2);
geometryColumn.truncate(geometryColumn.length() - 1);
mTableName = mTableName.mid(mTableName.find(".") + 1, mTableName.find(" (") - (mTableName.find(".") + 1));
// Keep a schema qualified table name for convenience later on.
if (mSchemaName.length() > 0)
mSchemaTableName = "\"" + mSchemaName + "\".\"" + mTableName + "\"";
else
mSchemaTableName = "\"" + mTableName + "\"";
/* populate the uri structure */
mUri.schema = mSchemaName;
mUri.table = mTableName;
mUri.geometryColumn = geometryColumn;
mUri.sql = sqlWhereClause;
// parse the connection info
QStringList conParts = QStringList::split(" ", connInfo);
QStringList parm = QStringList::split("=", conParts[0]);
if(parm.size() == 2)
{
mUri.host = parm[1];
}
parm = QStringList::split("=", conParts[1]);
if(parm.size() == 2)
{
mUri.database = parm[1];
}
parm = QStringList::split("=", conParts[2]);
if(parm.size() == 2)
{
mUri.port = parm[1];
}
parm = QStringList::split("=", conParts[3]);
if(parm.size() == 2)
{
mUri.username = parm[1];
}
parm = QStringList::split("=", conParts[4]);
if(parm.size() == 2)
{
mUri.password = parm[1];
}
/* end uri structure */
#ifdef QGISDEBUG
std::cerr << "Geometry column is: " << geometryColumn.toLocal8Bit().data() << std::endl;
std::cerr << "Schema is: " << mSchemaName.toLocal8Bit().data() << std::endl;
std::cerr << "Table name is: " << mTableName.toLocal8Bit().data() << std::endl;
#endif
//QString logFile = "./pg_provider_" + mTableName + ".log";
//pLog.open((const char *)logFile);
#ifdef QGISDEBUG
std::cerr << "Opened log file for " << mTableName.toLocal8Bit().data() << std::endl;
#endif
PGconn *pd = PQconnectdb((const char *) connInfo);
// check the connection status
if (PQstatus(pd) == CONNECTION_OK)
{
// store the connection for future use
connection = pd;
//set client encoding to unicode because QString uses UTF-8 anyway
#ifdef QGISDEBUG
qWarning("setting client encoding to UNICODE");
#endif
int errcode=PQsetClientEncoding(connection, "UNICODE");
#ifdef QGISDEBUG
if(errcode==0)
{
qWarning("encoding successfully set");
}
else if(errcode==-1)
{
qWarning("error in setting encoding");
}
else
{
qWarning("undefined return value from encoding setting");
}
#endif
#ifdef QGISDEBUG
std::cerr << "Checking for select permission on the relation\n";
#endif
// 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;
}
PQclear(testAccess);
/* Check to see if we have GEOS support and if not, warn the user about
the problems they will see :) */
#ifdef QGISDEBUG
std::cerr << "Checking for GEOS support" << std::endl;
#endif
if(!hasGEOS(pd))
{
showMessageBox(tr("No GEOS Support!"),
tr("Your PostGIS installation has no GEOS support.\n"
"Feature selection and identification will not "
"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();
// Populate the field vector for this layer. The field vector contains
// field name, type, length, and precision (if numeric)
sql = "select * from " + mSchemaTableName + " limit 1";
PGresult* result = PQexec(pd, (const char *) (sql.utf8()));
//--std::cout << "Field: Name, Type, Size, Modifier:" << std::endl;
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);
sql = "select typelem from pg_type where typelem = " + typOid + " and typlen = -1";
// //--std::cout << sql << std::endl;
PGresult *oidResult = PQexec(pd, (const char *) sql);
// get the oid of the "real" type
QString poid = PQgetvalue(oidResult, 0, PQfnumber(oidResult, "typelem"));
PQclear(oidResult);
sql = "select typname, typlen from pg_type where oid = " + poid;
// //--std::cout << sql << std::endl;
oidResult = PQexec(pd, (const char *) sql);
QString fieldType = PQgetvalue(oidResult, 0, 0);
QString fieldSize = PQgetvalue(oidResult, 0, 1);
PQclear(oidResult);
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);
sql = "select attnum from pg_attribute where attrelid = " + tableoid + " and attname = '" + fieldName + "'";
tresult = PQexec(pd, (const char *)(sql.utf8()));
QString attnum = PQgetvalue(tresult, 0, 0);
PQclear(tresult);
#ifdef QGISDEBUG
std::cerr << "Field: " << attnum.toLocal8Bit().data() << " maps to " << i << " " << fieldName.toLocal8Bit().data() << ", "
<< fieldType.toLocal8Bit().data() << " (" << fldtyp << "), " << fieldSize.toLocal8Bit().data() << ", "
<< fieldModifier << std::endl;
#endif
attributeFieldsIdMap[attnum.toInt()] = i;
if(fieldName!=geometryColumn)
{
attributeFields.push_back(QgsField(fieldName, fieldType, fieldSize.toInt(), fieldModifier));
}
}
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.
#ifndef QGISDEBUG
PQexec(connection, "set client_min_messages to error");
#endif
// Kick off the long running threads
#ifdef POSTGRESQL_THREADS
std::cout << "QgsPostgresProvider: About to touch mExtentThread" << std::endl;
mExtentThread.setConnInfo( connInfo );
mExtentThread.setTableName( mTableName );
mExtentThread.setSqlWhereClause( sqlWhereClause );
mExtentThread.setGeometryColumn( geometryColumn );
mExtentThread.setCallback( this );
std::cout << "QgsPostgresProvider: About to start mExtentThread" << std::endl;
mExtentThread.start();
std::cout << "QgsPostgresProvider: Main thread just dispatched mExtentThread" << std::endl;
std::cout << "QgsPostgresProvider: About to touch mCountThread" << std::endl;
mCountThread.setConnInfo( connInfo );
mCountThread.setTableName( mTableName );
mCountThread.setSqlWhereClause( sqlWhereClause );
mCountThread.setGeometryColumn( geometryColumn );
mCountThread.setCallback( this );
std::cout << "QgsPostgresProvider: About to start mCountThread" << std::endl;
mCountThread.start();
std::cout << "QgsPostgresProvider: Main thread just dispatched mCountThread" << std::endl;
#endif
}
else
{
// the table is not a geometry table
numberFeatures = 0;
valid = false;
#ifdef QGISDEBUG
std::cerr << "Invalid Postgres layer" << std::endl;
#endif
}
ready = false; // not ready to read yet cuz the cursor hasn't been created
} else {
valid = false;
//--std::cout << "Connection to database failed\n";
}
//fill type names into lists
mNumericalTypes.push_back("double precision");
mNumericalTypes.push_back("int4");
mNumericalTypes.push_back("int8");
mNonNumericalTypes.push_back("text");
mNonNumericalTypes.push_back("varchar(30)");
if (primaryKey.isEmpty())
{
valid = false;
}
// Close the database connection if the layer isn't going to be loaded.
if (!valid)
PQfinish(connection);
}
QgsPostgresProvider::~QgsPostgresProvider()
{
#ifdef POSTGRESQL_THREADS
std::cout << "QgsPostgresProvider: About to wait for mExtentThread" << std::endl;
mExtentThread.wait();
std::cout << "QgsPostgresProvider: Finished waiting for mExtentThread" << std::endl;
std::cout << "QgsPostgresProvider: About to wait for mCountThread" << std::endl;
mCountThread.wait();
std::cout << "QgsPostgresProvider: Finished waiting for mCountThread" << std::endl;
// Make sure all events from threads have been processed
// (otherwise they will get destroyed prematurely)
QApplication::sendPostedEvents(this, QGis::ProviderExtentCalcEvent);
QApplication::sendPostedEvents(this, QGis::ProviderCountCalcEvent);
#endif
PQfinish(connection);
QgsDebugMsg("QgsPostgresProvider: deconstructing.");
//pLog.flush();
}
QString QgsPostgresProvider::storageType()
{
return "PostgreSQL database with PostGIS extension";
}
//TODO - we may not need this function - consider removing it from
// the dataprovider.h interface
/**
* Get the first feature resutling from a select operation
* @return QgsFeature
*/
//TODO - this function is a stub and always returns 0
QgsFeature *QgsPostgresProvider::getFirstFeature(bool fetchAttributes)
{
QgsFeature *f = 0;
if (valid) {
//--std::cout << "getting first feature\n";
f = new QgsFeature();
/* f->setGeometry(getGeometryPointer(feat));
if(fetchAttributes){
getFeatureAttributes(feat, f);
} */
}
return f;
}
bool QgsPostgresProvider::getNextFeature(QgsFeature &feature, bool fetchAttributes)
{
return true;
}
/**
* Get the next feature resutling from a select operation
* Return 0 if there are no features in the selection set
* @return QgsFeature
*/
QgsFeature *QgsPostgresProvider::getNextFeature(bool fetchAttributes)
{
QgsFeature *f = 0;
int row = 0; // TODO: Make this useful
if (valid){
QString fetch = "fetch forward 1 from qgisf";
queryResult = PQexec(connection, (const char *)fetch);
// std::cerr << "Error: " << PQerrorMessage(connection) << std::endl;
// std::cerr << "Fetched " << PQntuples(queryResult) << "rows" << std::endl;
if(PQntuples(queryResult) == 0){
PQexec(connection, "end work");
ready = false;
return 0;
}
// //--std::cout <<"Raw value of the geometry field: " << PQgetvalue(queryResult,0,PQfnumber(queryResult,"qgs_feature_geometry")) << std::endl;
//--std::cout << "Length of oid is " << PQgetlength(queryResult,0, PQfnumber(queryResult,"oid")) << std::endl;
// get the value of the primary key based on type
int oid = *(int *)PQgetvalue(queryResult, row, PQfnumber(queryResult,primaryKey));
#ifdef QGISDEBUG
// std::cerr << "OID from database: " << oid << std::endl;
#endif
if (swapEndian)
oid = ntohl(oid); // convert oid to opposite endian
// oid is the key to be used in fetching attributes if
// fetchAttributes = true
#ifdef QGISDEBUG
// std::cerr << "Using OID: " << oid << std::endl;
#endif
f = new QgsFeature(oid);
if (fetchAttributes)
getFeatureAttributes(oid, row, f);
int returnedLength = PQgetlength(queryResult, row, PQfnumber(queryResult,"qgs_feature_geometry"));
//--std::cerr << __FILE__ << ":" << __LINE__ << " Returned length is " << returnedLength << std::endl;
if(returnedLength > 0)
{
unsigned char *feature = new unsigned char[returnedLength + 1];
memset(feature, '\0', returnedLength + 1);
memcpy(feature, PQgetvalue(queryResult, row, PQfnumber(queryResult,"qgs_feature_geometry")), returnedLength);
#ifdef QGISDEBUG
// a bit verbose
//int wkbType = *((int *) (feature + 1));
//std::cout << "WKBtype is: " << wkbType << std::endl;
#endif
f->setGeometryAndOwnership(feature, returnedLength + 1);
}
else
{
//--std::cout <<"Couldn't get the feature geometry in binary form" << std::endl;
}
PQclear(queryResult);
}
else
{
//--std::cout << "Read attempt on an invalid postgresql data source\n";
}
return f;
}
// // TODO: Remove completely (see morb_au)
// QgsFeature* QgsPostgresProvider::getNextFeature(std::list<int> const & attlist)
// {
// return getNextFeature(attlist, 1);
// }
QgsFeature* QgsPostgresProvider::getNextFeature(std::list<int> const & attlist, int featureQueueSize)
{
QgsFeature *f = 0;
if (valid)
{
// Top up our queue if it is empty
if (mFeatureQueue.empty())
{
if (featureQueueSize < 1)
{
featureQueueSize = 1;
}
QString fetch = QString("fetch forward %1 from qgisf")
.arg(featureQueueSize);
queryResult = PQexec(connection, (const char *)fetch);
int rows = PQntuples(queryResult);
if (rows == 0)
{
#ifdef QGISDEBUG
std::cerr << "End of features.\n";
#endif
PQexec(connection, "end work");
ready = false;
return 0;
}
for (int row = 0; row < rows; row++)
{
int oid = *(int *)PQgetvalue(queryResult, row, PQfnumber(queryResult,primaryKey));
#ifdef QGISDEBUG
// std::cerr << "Primary key type is " << primaryKeyType << std::endl;
#endif
if (swapEndian)
oid = ntohl(oid); // convert oid to opposite endian
f = new QgsFeature(oid);
if(!attlist.empty())
{
getFeatureAttributes(oid, row, f, attlist);
}
int returnedLength = PQgetlength(queryResult, row, PQfnumber(queryResult,"qgs_feature_geometry"));
if(returnedLength > 0)
{
unsigned char *feature = new unsigned char[returnedLength + 1];
memset(feature, '\0', returnedLength + 1);
memcpy(feature, PQgetvalue(queryResult, row, PQfnumber(queryResult,"qgs_feature_geometry")), returnedLength);
#ifdef QGISDEBUG
// Too verbose
//int wkbType = *((int *) (feature + 1));
//std::cout << "WKBtype is: " << wkbType << std::endl;
#endif
f->setGeometryAndOwnership(feature, returnedLength + 1);
}
else
{
//--std::cout <<"Couldn't get the feature geometry in binary form" << std::endl;
}
#ifdef QGISDEBUG
// std::cout << "QgsPostgresProvider::getNextFeature: pushing " << f->featureId() << std::endl;
#endif
mFeatureQueue.push(f);
} // for each row in queue
#ifdef QGISDEBUG
// std::cout << "QgsPostgresProvider::getNextFeature: retrieved batch of features." << std::endl;
#endif
PQclear(queryResult);
} // if new queue is required
// Now return the next feature from the queue
f = mFeatureQueue.front();
mFeatureQueue.pop();
}
else
{
//--std::cout << "Read attempt on an invalid postgresql data source\n";
}
#ifdef QGISDEBUG
// std::cout << "QgsPostgresProvider::getNextFeature: returning " << f->featureId() << std::endl;
#endif
return f;
}
/**
* Select features based on a bounding rectangle. Features can be retrieved
* with calls to getFirstFeature and getNextFeature.
* @param mbr QgsRect containing the extent to use in selecting features
*/
void QgsPostgresProvider::select(QgsRect * rect, bool useIntersect)
{
// spatial query to select features
#ifdef QGISDEBUG
std::cerr << "Selection rectangle is " << *rect << std::endl;
std::cerr << "Selection polygon is " << rect->asPolygon().toLocal8Bit().data() << std::endl;
#endif
QString declare = QString("declare qgisf binary cursor for select "
+ primaryKey
+ ",asbinary(%1,'%2') as qgs_feature_geometry from %3").arg(geometryColumn).arg(endianString()).arg(mSchemaTableName);
#ifdef QGISDEBUG
std::cout << "Binary cursor: " << declare.toLocal8Bit().data() << std::endl;
#endif
if(useIntersect){
// declare += " where intersects(" + geometryColumn;
// declare += ", GeometryFromText('BOX3D(" + rect->asWKTCoords();
// declare += ")'::box3d,";
// declare += srid;
// declare += "))";
// Contributed by #qgis irc "creeping"
// This version actually invokes PostGIS's use of spatial indexes
declare += " where " + geometryColumn;
declare += " && setsrid('BOX3D(" + rect->asWKTCoords();
declare += ")'::box3d,";
declare += srid;
declare += ")";
declare += " and intersects(" + geometryColumn;
declare += ", setsrid('BOX3D(" + rect->asWKTCoords();
declare += ")'::box3d,";
declare += srid;
declare += "))";
}else{
declare += " where " + geometryColumn;
declare += " && setsrid('BOX3D(" + rect->asWKTCoords();
declare += ")'::box3d,";
declare += srid;
declare += ")";
}
if(sqlWhereClause.length() > 0)
{
declare += " and (" + sqlWhereClause + ")";
}
#ifdef QGISDEBUG
std::cerr << "Selecting features using: " << declare.toLocal8Bit().data() << std::endl;
#endif
// set up the cursor
if(ready){
PQexec(connection, "end work");
}
PQexec(connection,"begin work");
PQexec(connection, (const char *)(declare.utf8()));
// TODO - see if this deallocates member features
mFeatureQueue.empty();
}
QgsDataSourceURI * QgsPostgresProvider::getURI()
{
return &mUri;
}
/**
* Identify features within the search radius specified by rect
* @param rect Bounding rectangle of search radius
* @return std::vector containing QgsFeature objects that intersect rect
*/
std::vector<QgsFeature>& QgsPostgresProvider::identify(QgsRect * rect)
{
features.clear();
// select the features
select(rect);
return features;
}
/* unsigned char * QgsPostgresProvider::getGeometryPointer(OGRFeature *fet){
// OGRGeometry *geom = fet->GetGeometryRef();
unsigned char *gPtr=0;
// get the wkb representation
gPtr = new unsigned char[geom->WkbSize()];
geom->exportToWkb((OGRwkbByteOrder) endian(), gPtr);
return gPtr;
} */
void QgsPostgresProvider::setExtent( QgsRect* newExtent )
{
layerExtent.setXmax( newExtent->xMax() );
layerExtent.setXmin( newExtent->xMin() );
layerExtent.setYmax( newExtent->yMax() );
layerExtent.setYmin( newExtent->yMin() );
}
// TODO - make this function return the real extent_
QgsRect *QgsPostgresProvider::extent()
{
return &layerExtent; //extent_->MinX, extent_->MinY, extent_->MaxX, extent_->MaxY);
}
/**
* Return the feature type
*/
int QgsPostgresProvider::geometryType() const
{
return geomType;
}
/**
* Return the feature type
*/
long QgsPostgresProvider::featureCount() const
{
return numberFeatures;
}
/**
* Return the number of fields
*/
int QgsPostgresProvider::fieldCount() const
{
return attributeFields.size();
}
/**
* Fetch attributes for a selected feature
*/
void QgsPostgresProvider::getFeatureAttributes(int key, int &row, QgsFeature *f) {
QString sql = QString("select * from %1 where %2 = %3").arg(mSchemaTableName).arg(primaryKey).arg(key);
#ifdef QGISDEBUG
std::cerr << "QgsPostgresProvider::getFeatureAttributes using: " << sql.toLocal8Bit().data() << std::endl;
#endif
PGresult *attr = PQexec(connection, (const char *)(sql.utf8()));
for (int i = 0; i < PQnfields(attr); i++) {
QString fld = PQfname(attr, i);
// Dont add the WKT representation of the geometry column to the identify
// results
if(fld != geometryColumn){
// Add the attribute to the feature
//QString val = mEncoding->toUnicode(PQgetvalue(attr,0, i));
QString val = QString::fromUtf8 (PQgetvalue(attr, row, i));
f->addAttribute(fld, val);
}
}
PQclear(attr);
}
/**Fetch attributes with indices contained in attlist*/
void QgsPostgresProvider::getFeatureAttributes(int key, int &row,
QgsFeature *f,
std::list<int> const & attlist)
{
std::list<int>::const_iterator iter;
for(iter=attlist.begin();iter!=attlist.end();++iter)
{
QString sql = QString("select %1 from %2 where %3 = %4")
.arg(fields()[*iter].name())
.arg(mSchemaTableName)
.arg(primaryKey)
.arg(key);//todo: only query one attribute
PGresult *attr = PQexec(connection, (const char *)(sql.utf8()));
QString fld = PQfname(attr, 0);
// Dont add the WKT representation of the geometry column to the identify
// results
if(fld != geometryColumn)
{
// Add the attribute to the feature
QString val = QString::fromUtf8(PQgetvalue(attr, 0, 0));
f->addAttribute(fld, val);
}
PQclear(attr);
}
}
void QgsPostgresProvider::getFeatureGeometry(int key, QgsFeature *f)
{
if (!valid)
{
return;
}
QString cursor = QString("declare qgisf binary cursor for "
"select asbinary(%1,'%2') from %3 where %4 = %5")
.arg(geometryColumn)
.arg(endianString())
.arg(mSchemaTableName)
.arg(primaryKey)
.arg(key);
#ifdef QGISDEBUG
std::cerr << "QgsPostgresProvider::getFeatureGeometry using: " << cursor.toLocal8Bit().data() << std::endl;
#endif
PQexec(connection, "begin work");
PQexec(connection, (const char *)(cursor.utf8()));
QString fetch = "fetch forward 1 from qgisf";
PGresult *geomResult = PQexec(connection, (const char *)fetch);
if (PQntuples(geomResult) == 0)
{
// Nothing found - therefore nothing to change
PQexec(connection,"end work");
PQclear(geomResult);
return;
}
int row = 0;
int returnedLength = PQgetlength(geomResult, row, 0);
if(returnedLength > 0)
{
unsigned char *wkbgeom = new unsigned char[returnedLength];
memcpy(wkbgeom, PQgetvalue(geomResult, row, 0), returnedLength);
f->setGeometryAndOwnership(wkbgeom, returnedLength);
}
else
{
//--std::cout <<"Couldn't get the feature geometry in binary form" << std::endl;
}
PQclear(geomResult);
PQexec(connection,"end work");
}
std::vector<QgsField> const & QgsPostgresProvider::fields() const
{
return attributeFields;
}
void QgsPostgresProvider::reset()
{
// reset the cursor to the first record
//--std::cout << "Resetting the cursor to the first record " << std::endl;
QString declare = QString("declare qgisf binary cursor for select " +
primaryKey +
",asbinary(%1,'%2') as qgs_feature_geometry from %3").arg(geometryColumn)
.arg(endianString()).arg(mSchemaTableName);
if(sqlWhereClause.length() > 0)
{
declare += " where " + sqlWhereClause;
}
//--std::cout << "Selecting features using: " << declare << std::endl;
#ifdef QGISDEBUG
std::cerr << "Setting up binary cursor: " << declare.toLocal8Bit().data() << std::endl;
#endif
// set up the cursor
PQexec(connection,"end work");
PQexec(connection,"begin work");
PQexec(connection, (const char *)(declare.utf8()));
//--std::cout << "Error: " << PQerrorMessage(connection) << std::endl;
// TODO - see if this deallocates member features
mFeatureQueue.empty();
ready = true;
}
/* QString QgsPostgresProvider::getFieldTypeName(PGconn * pd, int oid)
{
QString typOid = QString().setNum(oid);
QString sql = "select typelem from pg_type where typelem = " + typOid + " and typlen = -1";
////--std::cout << sql << std::endl;
PGresult *result = PQexec(pd, (const char *) sql);
// get the oid of the "real" type
QString poid = PQgetvalue(result, 0, PQfnumber(result, "typelem"));
PQclear(result);
sql = "select typname, typlen from pg_type where oid = " + poid;
// //--std::cout << sql << std::endl;
result = PQexec(pd, (const char *) sql);
QString typeName = PQgetvalue(result, 0, 0);
QString typeLen = PQgetvalue(result, 0, 1);
PQclear(result);
typeName += "(" + typeLen + ")";
return typeName;
} */
/** @todo XXX Perhaps this should be promoted to QgsDataProvider? */
QString QgsPostgresProvider::endianString()
{
switch ( endian() )
{
case QgsDataProvider::NDR :
return QString("NDR");
break;
case QgsDataProvider::XDR :
return QString("XDR");
break;
default :
return QString("UNKNOWN");
}
}
QString QgsPostgresProvider::getPrimaryKey()
{
// check to see if there is an unique index on the relation, which
// can be used as a key into the table. Primary keys are always
// unique indices, so we catch them as well.
QString sql = "select indkey from pg_index where indisunique = 't' and "
"indrelid = (select oid from pg_class where relname = '"
+ mTableName + "' and relnamespace = (select oid from pg_namespace where "
"nspname = '" + mSchemaName + "'))";
#ifdef QGISDEBUG
std::cerr << "Getting unique index using '" << sql.toLocal8Bit().data() << "'\n";
#endif
PGresult *pk = executeDbCommand(connection, sql);
#ifdef QGISDEBUG
std::cerr << "Got " << PQntuples(pk) << " rows.\n";
#endif
QStringList log;
// if we got no tuples we ain't got no unique index :)
if (PQntuples(pk) == 0)
{
#ifdef QGISDEBUG
std::cerr << "Relation has no unique index -- "
<< "investigating alternatives\n";
#endif
// Two options here. If the relation is a table, see if there is
// an oid column that can be used instead.
// If the relation is a view try to find a suitable column to use as
// the primary key.
sql = "select relkind from pg_class where relname = '" + mTableName +
"' and relnamespace = (select oid from pg_namespace where "
"nspname = '" + mSchemaName + "')";
PGresult* tableType = executeDbCommand(connection, sql);
QString type = PQgetvalue(tableType, 0, 0);
PQclear(tableType);
primaryKey = "";
if (type == "r") // the relation is a table
{
#ifdef QGISDEBUG
std::cerr << "Relation is a table. Checking to see if it has an "
<< "oid column.\n";
#endif
// If there is an oid on the table, use that instead,
// otherwise give up
sql = "select attname from pg_attribute where attname = 'oid' and "
"attrelid = (select oid from pg_class where relname = '" +
mTableName + "' and relnamespace = (select oid from pg_namespace "
"where nspname = '" + mSchemaName + "'))";
PGresult* oidCheck = executeDbCommand(connection, sql);
if (PQntuples(oidCheck) != 0)
{
// Could warn the user here that performance will suffer if
// oid isn't indexed (and that they may want to add a
// primary key to the table)
primaryKey = "oid";
primaryKeyType = "int4";
}
else
{
showMessageBox(tr("No suitable key column in table"),
tr("The table has no column suitable for use as a key.\n\n"
"Qgis requires that the table either has a column of type\n"
"int4 with a unique constraint on it (which includes the\n"
"primary key) or has a PostgreSQL oid column.\n"));
}
PQclear(oidCheck);
}
else if (type == "v") // the relation is a view
{
// Have a poke around the view to see if any of the columns
// could be used as the primary key.
tableCols cols;
// Given a schema.view, populate the cols variable with the
// schema.table.column's that underly the view columns.
findColumns(cols);
// From the view columns, choose one for which the underlying
// column is suitable for use as a key into the view.
primaryKey = chooseViewColumn(cols);
}
else
qWarning("Unexpected relation type of '" + type + "'.");
}
else // have some unique indices on the table. Now choose one...
{
// choose which (if more than one) unique index to use
std::vector<std::pair<QString, QString> > suitableKeyColumns;
for (int i = 0; i < PQntuples(pk); ++i)