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qgspostgresprovider.cpp
3193 lines (2676 loc) · 96.2 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. *
* *
***************************************************************************/
/* $Id$ */
// for htonl
#ifdef WIN32
#include <winsock.h>
#else
#include <netinet/in.h>
#endif
#include <cassert>
#include <qgis.h>
#include <qgsapplication.h>
#include <qgsfeature.h>
#include <qgsfield.h>
#include <qgsgeometry.h>
#include <qgsmessageoutput.h>
#include <qgsrectangle.h>
#include <qgscoordinatereferencesystem.h>
#include "qgsprovidercountcalcevent.h"
#include "qgsproviderextentcalcevent.h"
#include "qgspostgresprovider.h"
#include "qgspostgrescountthread.h"
#include "qgspostgresextentthread.h"
#include "qgspostgisbox3d.h"
#include "qgslogger.h"
const QString POSTGRES_KEY = "postgres";
const QString POSTGRES_DESCRIPTION = "PostgreSQL/PostGIS data provider";
QMap<QString, QgsPostgresProvider::Conn *> QgsPostgresProvider::Conn::connectionsRO;
QMap<QString, QgsPostgresProvider::Conn *> QgsPostgresProvider::Conn::connectionsRW;
int QgsPostgresProvider::providerIds = 0;
QgsPostgresProvider::QgsPostgresProvider( QString const & uri )
: QgsVectorDataProvider( uri ),
mFetching( false ),
geomType( QGis::WKBUnknown ),
mFeatureQueueSize( 200 )
{
// assume this is a valid layer until we determine otherwise
valid = true;
providerId = providerIds++;
QgsDebugMsg( "Postgresql Layer Creation" );
QgsDebugMsg( "URI: " + uri );
mUri = QgsDataSourceURI( uri );
/* populate members from the uri structure */
mSchemaName = mUri.schema();
mTableName = mUri.table();
geometryColumn = mUri.geometryColumn();
sqlWhereClause = mUri.sql();
primaryKey = mUri.keyColumn();
// Keep a schema qualified table name for convenience later on.
mSchemaTableName = mUri.quotedTablename();
QgsDebugMsg( "Table name is " + mTableName );
QgsDebugMsg( "SQL is " + sqlWhereClause );
QgsDebugMsg( "Connection info is " + mUri.connectionInfo() );
QgsDebugMsg( "Geometry column is: " + geometryColumn );
QgsDebugMsg( "Schema is: " + mSchemaName );
QgsDebugMsg( "Table name is: " + mTableName );
connectionRW = NULL;
connectionRO = Conn::connectDb( mUri.connectionInfo(), true );
if ( connectionRO == NULL )
{
valid = false;
return;
}
QgsDebugMsg( "Checking for permissions on the relation" );
// Check that we can read from the table (i.e., we have
// select permission).
QString sql = QString( "select * from %1 limit 1" ).arg( mSchemaTableName );
Result testAccess = connectionRO->PQexec( sql );
if ( PQresultStatus( testAccess ) != PGRES_TUPLES_OK )
{
showMessageBox( tr( "Unable to access relation" ),
tr( "Unable to access the %1 relation.\nThe error message from the database was:\n%2.\nSQL: %3" )
.arg( mSchemaTableName )
.arg( QString::fromUtf8( PQresultErrorMessage( testAccess ) ) )
.arg( sql ) );
valid = false;
disconnectDb();
return;
}
sql = QString( "SELECT "
"has_table_privilege(%1,'DELETE'),"
"has_table_privilege(%1,'UPDATE'),"
"has_table_privilege(%1,'INSERT'),"
"current_schema()" )
.arg( quotedValue( mSchemaTableName ) );
testAccess = connectionRO->PQexec( sql );
if ( PQresultStatus( testAccess ) != PGRES_TUPLES_OK )
{
showMessageBox( tr( "Unable to access relation" ),
tr( "Unable to determine table access privileges for the %1 relation.\nThe error message from the database was:\n%2.\nSQL: %3" )
.arg( mSchemaTableName )
.arg( QString::fromUtf8( PQresultErrorMessage( testAccess ) ) )
.arg( sql ) );
valid = false;
disconnectDb();
return;
}
// postgres has fast access to features at id (thanks to primary key / unique index)
// the latter flag is here just for compatibility
enabledCapabilities = QgsVectorDataProvider::SelectAtId | QgsVectorDataProvider::SelectGeometryAtId;
if ( QString::fromUtf8( PQgetvalue( testAccess, 0, 0 ) ) == "t" )
{
// DELETE
enabledCapabilities |= QgsVectorDataProvider::DeleteFeatures;
}
if ( QString::fromUtf8( PQgetvalue( testAccess, 0, 1 ) ) == "t" )
{
// UPDATE
enabledCapabilities |= QgsVectorDataProvider::ChangeGeometries | QgsVectorDataProvider::ChangeAttributeValues;
}
if ( QString::fromUtf8( PQgetvalue( testAccess, 0, 2 ) ) == "t" )
{
// INSERT
enabledCapabilities |= QgsVectorDataProvider::AddFeatures;
}
mCurrentSchema = QString::fromUtf8( PQgetvalue( testAccess, 0, 3 ) );
if ( mCurrentSchema == mSchemaName )
{
mUri.clearSchema();
setDataSourceUri( mUri.uri() );
}
if ( mSchemaName == "" )
mSchemaName = mCurrentSchema;
sql = QString( "SELECT 1 FROM pg_class,pg_namespace WHERE "
"pg_class.relnamespace=pg_namespace.oid AND "
"pg_get_userbyid(relowner)=current_user AND "
"relname=%1 AND nspname=%2" )
.arg( quotedValue( mTableName ) )
.arg( quotedValue( mSchemaName ) );
testAccess = connectionRO->PQexec( sql );
if ( PQresultStatus( testAccess ) == PGRES_TUPLES_OK && PQntuples( testAccess ) == 1 )
{
enabledCapabilities |= QgsVectorDataProvider::AddAttributes | QgsVectorDataProvider::DeleteAttributes;
}
if ( !getGeometryDetails() ) // gets srid and geometry type
{
// the table is not a geometry table
featuresCounted = 0;
valid = false;
QgsDebugMsg( "Invalid Postgres layer" );
disconnectDb();
return;
}
deduceEndian();
calculateExtents();
getFeatureCount();
// load the field list
loadFields();
// 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
connectionRO->PQexecNR( "set client_min_messages to error" );
#endif
// Kick off the long running threads
#ifdef POSTGRESQL_THREADS
QgsDebugMsg( "About to touch mExtentThread" );
mExtentThread.setConnInfo( mUri.connectionInfo );
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.connectionInfo );
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" );
#endif
//fill type names into sets
mNativeTypes
// integer types
<< QgsVectorDataProvider::NativeType( tr( "Whole number (smallint - 16bit)" ), "int2", QVariant::Int )
<< QgsVectorDataProvider::NativeType( tr( "Whole number (integer - 32bit)" ), "int4", QVariant::Int )
<< QgsVectorDataProvider::NativeType( tr( "Whole number (integer - 64bit)" ), "int8", QVariant::LongLong )
<< QgsVectorDataProvider::NativeType( tr( "Decimal number (numeric)" ), "numeric", QVariant::LongLong, 1, 20, 0, 20 )
<< QgsVectorDataProvider::NativeType( tr( "Decimal number (decimal)" ), "decimal", QVariant::LongLong, 1, 20, 0, 20 )
// floating point
<< QgsVectorDataProvider::NativeType( tr( "Decimal number (real)" ), "real", QVariant::Double )
<< QgsVectorDataProvider::NativeType( tr( "Decimal number (double)" ), "double precision", QVariant::Double )
// string types
<< QgsVectorDataProvider::NativeType( tr( "Text, fixed length (char)" ), "char", QVariant::String, 1, 255 )
<< QgsVectorDataProvider::NativeType( tr( "Text, limited variable length (varchar)" ), "varchar", QVariant::String, 1, 255 )
<< QgsVectorDataProvider::NativeType( tr( "Text, unlimited length (text)" ), "text", QVariant::String )
;
if ( primaryKey.isEmpty() )
{
valid = false;
}
// Close the database connection if the layer isn't going to be loaded.
if ( !valid )
disconnectDb();
}
QgsPostgresProvider::~QgsPostgresProvider()
{
#ifdef POSTGRESQL_THREADS
QgsDebugMsg( "About to wait for mExtentThread" );
mExtentThread.wait();
QgsDebugMsg( "Finished waiting for mExtentThread" );
QgsDebugMsg( "About to wait for mCountThread" );
mCountThread.wait();
QgsDebugMsg( "Finished waiting for mCountThread" );
// 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
disconnectDb();
QgsDebugMsg( "deconstructing." );
//pLog.flush();
}
QgsPostgresProvider::Conn *QgsPostgresProvider::Conn::connectDb( const QString & conninfo, bool readonly )
{
QMap<QString, QgsPostgresProvider::Conn *> &connections =
readonly ? QgsPostgresProvider::Conn::connectionsRO : QgsPostgresProvider::Conn::connectionsRW;
if ( connections.contains( conninfo ) )
{
QgsDebugMsg( QString( "Using cached connection for %1" ).arg( conninfo ) );
connections[conninfo]->ref++;
return connections[conninfo];
}
QgsDebugMsg( QString( "New postgres connection for " ) + conninfo );
PGconn *pd = PQconnectdb( conninfo.toLocal8Bit() ); // use what is set based on locale; after connecting, use Utf8
// check the connection status
if ( PQstatus( pd ) != CONNECTION_OK )
{
QgsDebugMsg( "Connection to database failed" );
return NULL;
}
//set client encoding to unicode because QString uses UTF-8 anyway
QgsDebugMsg( "setting client encoding to UNICODE" );
int errcode = PQsetClientEncoding( pd, QString( "UNICODE" ).toLocal8Bit() );
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( "Connection to the database was successful" );
Conn *conn = new Conn( pd );
/* Check to see if we have working PostGIS support */
if ( conn->postgisVersion().isNull() )
{
showMessageBox( tr( "No PostGIS Support!" ),
tr( "Your database has no working PostGIS support.\n" ) );
conn->PQfinish();
delete conn;
return NULL;
}
connections.insert( conninfo, conn );
/* Check to see if we have GEOS support and if not, warn the user about
the problems they will see :) */
QgsDebugMsg( "Checking for GEOS support" );
if ( !conn->hasGEOS() )
{
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)" ) );
}
return conn;
}
void QgsPostgresProvider::disconnectDb()
{
if ( mFetching )
{
connectionRO->closeCursor( QString( "qgisf%1" ).arg( providerId ) );
mFetching = false;
}
if ( connectionRO )
{
Conn::disconnectRO( connectionRO );
}
if ( connectionRW )
{
Conn::disconnectRW( connectionRW );
}
}
void QgsPostgresProvider::Conn::disconnectRW( Conn *&connection )
{
disconnect( connectionsRW, connection );
}
void QgsPostgresProvider::Conn::disconnectRO( Conn *&connection )
{
disconnect( connectionsRO, connection );
}
void QgsPostgresProvider::Conn::disconnect( QMap<QString, Conn *>& connections, Conn *&conn )
{
QMap<QString, Conn *>::iterator i;
for ( i = connections.begin(); i != connections.end() && i.value() != conn; i++ )
;
assert( i.value() == conn );
assert( i.value()->ref > 0 );
if ( --i.value()->ref == 0 )
{
i.value()->PQfinish();
delete i.value();
connections.remove( i.key() );
}
conn = NULL;
}
QString QgsPostgresProvider::storageType() const
{
return "PostgreSQL database with PostGIS extension";
}
QString QgsPostgresProvider::fieldExpression( const QgsField &fld ) const
{
const QString &type = fld.typeName();
if ( type == "money" )
{
return QString( "cash_out(%1)" ).arg( quotedIdentifier( fld.name() ) );
}
else if ( type.startsWith( "_" ) )
{
return QString( "array_out(%1)" ).arg( quotedIdentifier( fld.name() ) );
}
else if ( type == "bool" )
{
return QString( "boolout(%1)" ).arg( quotedIdentifier( fld.name() ) );
}
else if ( type == "geometry" )
{
return QString( "asewkt(%1)" ).arg( quotedIdentifier( fld.name() ) );
}
else
{
return quotedIdentifier( fld.name() ) + "::text";
}
}
bool QgsPostgresProvider::declareCursor(
const QString &cursorName,
const QgsAttributeList &fetchAttributes,
bool fetchGeometry,
QString whereClause )
{
try
{
QString query = QString( "select %1" ).arg( quotedIdentifier( primaryKey ) );
if ( fetchGeometry )
{
query += QString( ",asbinary(%1,'%2')" )
.arg( quotedIdentifier( geometryColumn ) )
.arg( endianString() );
}
for ( QgsAttributeList::const_iterator it = fetchAttributes.constBegin(); it != fetchAttributes.constEnd(); ++it )
{
const QgsField &fld = field( *it );
if ( fld.name() == primaryKey )
continue;
query += "," + fieldExpression( fld );
}
query += " from " + mSchemaTableName;
if ( !whereClause.isEmpty() )
query += QString( " where %1" ).arg( whereClause );
return connectionRO->openCursor( cursorName, query );
}
catch ( PGFieldNotFound )
{
return false;
}
}
bool QgsPostgresProvider::getFeature( PGresult *queryResult, int row, bool fetchGeometry,
QgsFeature &feature,
const QgsAttributeList &fetchAttributes )
{
try
{
int oid;
if ( primaryKeyType != "tid" )
{
oid = *( int * )PQgetvalue( queryResult, row, 0 );
if ( swapEndian )
oid = ntohl( oid ); // convert oid to opposite endian
}
else if ( PQgetlength( queryResult, row, 0 ) == 6 )
{
char *data = PQgetvalue( queryResult, row, 0 );
int block = *( int * )data;
int offset = *( short * )( data + sizeof( int ) );
if ( swapEndian )
{
block = ntohl( block );
offset = ntohs( offset );
}
if ( block > 0xffff )
{
QgsDebugMsg( QString( "block number %1 exceeds 16 bit" ).arg( block ) );
return false;
}
oid = ( block << 16 ) + offset;
}
else
{
QgsDebugMsg( QString( "expecting 6 bytes for tid (found %1 bytes)" ).arg( PQgetlength( queryResult, row, 0 ) ) );
return false;
}
feature.setFeatureId( oid );
int col; // first attribute column after geometry
if ( fetchGeometry )
{
int returnedLength = PQgetlength( queryResult, row, 1 );
if ( returnedLength > 0 )
{
unsigned char *featureGeom = new unsigned char[returnedLength + 1];
memset( featureGeom, '\0', returnedLength + 1 );
memcpy( featureGeom, PQgetvalue( queryResult, row, 1 ), returnedLength );
feature.setGeometryAndOwnership( featureGeom, returnedLength + 1 );
}
else
{
feature.setGeometryAndOwnership( 0, 0 );
QgsDebugMsg( "Couldn't get the feature geometry in binary form" );
}
col = 2;
}
else
{
col = 1;
}
// iterate attributes
for ( QgsAttributeList::const_iterator it = fetchAttributes.constBegin(); it != fetchAttributes.constEnd(); it++ )
{
const QgsField &fld = field( *it );
if ( fld.name() == primaryKey )
{
// primary key was already processed
feature.addAttribute( *it, convertValue( fld.type(), QString::number( oid ) ) );
continue;
}
if ( !PQgetisnull( queryResult, row, col ) )
{
feature.addAttribute( *it, convertValue( fld.type(), QString::fromUtf8( PQgetvalue( queryResult, row, col ) ) ) );
}
else
{
feature.addAttribute( *it, QVariant( QString::null ) );
}
col++;
}
return true;
}
catch ( PGFieldNotFound )
{
return false;
}
}
void QgsPostgresProvider::select( QgsAttributeList fetchAttributes, QgsRectangle rect, bool fetchGeometry, bool useIntersect )
{
QString cursorName = QString( "qgisf%1" ).arg( providerId );
if ( mFetching )
{
connectionRO->closeCursor( cursorName );
mFetching = false;
while ( !mFeatureQueue.empty() )
{
mFeatureQueue.pop();
}
}
QString whereClause;
if ( !rect.isEmpty() )
{
if ( useIntersect )
{
// Contributed by #qgis irc "creeping"
// This version actually invokes PostGIS's use of spatial indexes
whereClause = QString( "%1 && setsrid('BOX3D(%2)'::box3d,%3) and intersects(%1,setsrid('BOX3D(%2)'::box3d,%3))" )
.arg( quotedIdentifier( geometryColumn ) )
.arg( rect.asWktCoordinates() )
.arg( srid );
}
else
{
whereClause = QString( "%1 && setsrid('BOX3D(%2)'::box3d,%3)" )
.arg( quotedIdentifier( geometryColumn ) )
.arg( rect.asWktCoordinates() )
.arg( srid );
}
}
if ( !sqlWhereClause.isEmpty() )
{
if ( !whereClause.isEmpty() )
whereClause += " and ";
whereClause += "(" + sqlWhereClause + ")";
}
mFetchGeom = fetchGeometry;
mAttributesToFetch = fetchAttributes;
if ( !declareCursor( cursorName, fetchAttributes, fetchGeometry, whereClause ) )
return;
mFetching = true;
}
bool QgsPostgresProvider::nextFeature( QgsFeature& feature )
{
feature.setValid( false );
QString cursorName = QString( "qgisf%1" ).arg( providerId );
if ( !valid )
{
QgsDebugMsg( "Read attempt on an invalid postgresql data source" );
return false;
}
if ( mFeatureQueue.empty() )
{
QString fetch = QString( "fetch forward %1 from %2" ).arg( mFeatureQueueSize ).arg( cursorName );
if ( connectionRO->PQsendQuery( fetch ) == 0 ) // fetch features asynchronously
{
QgsDebugMsg( "PQsendQuery failed (1)" );
}
Result queryResult;
while (( queryResult = connectionRO->PQgetResult() ) )
{
int rows = PQntuples( queryResult );
if ( rows == 0 )
continue;
for ( int row = 0; row < rows; row++ )
{
mFeatureQueue.push( QgsFeature() );
getFeature( queryResult, row, mFetchGeom, mFeatureQueue.back(), mAttributesToFetch );
} // for each row in queue
}
}
if ( mFeatureQueue.empty() )
{
QgsDebugMsg( "End of features" );
connectionRO->closeCursor( cursorName );
mFetching = false;
return false;
}
// Now return the next feature from the queue
if ( mFetchGeom )
{
QgsGeometry* featureGeom = mFeatureQueue.front().geometryAndOwnership();
feature.setGeometry( featureGeom );
}
else
{
feature.setGeometryAndOwnership( 0, 0 );
}
feature.setFeatureId( mFeatureQueue.front().id() );
feature.setAttributeMap( mFeatureQueue.front().attributeMap() );
mFeatureQueue.pop();
feature.setValid( true );
return true;
}
QString QgsPostgresProvider::whereClause( int featureId ) const
{
QString whereClause;
if ( primaryKeyType != "tid" )
{
whereClause = QString( "%1=%2" ).arg( quotedIdentifier( primaryKey ) ).arg( featureId );
}
else
{
whereClause = QString( "%1='(%2,%3)'" ).arg( quotedIdentifier( primaryKey ) ).arg( featureId >> 16 ).arg( featureId & 0xffff );
}
if ( !sqlWhereClause.isEmpty() )
{
if ( !whereClause.isEmpty() )
whereClause += " and ";
whereClause += "(" + sqlWhereClause + ")";
}
return whereClause;
}
bool QgsPostgresProvider::featureAtId( int featureId, QgsFeature& feature, bool fetchGeometry, QgsAttributeList fetchAttributes )
{
QString cursorName = QString( "qgisfid%1" ).arg( providerId );
if ( !declareCursor( cursorName, fetchAttributes, fetchGeometry, whereClause( featureId ) ) )
return false;
Result queryResult = connectionRO->PQexec( QString( "fetch forward 1 from %1" ).arg( cursorName ) );
if ( queryResult == 0 )
return false;
int rows = PQntuples( queryResult );
if ( rows == 0 )
{
QgsDebugMsg( QString( "feature %1 not found" ).arg( featureId ) );
connectionRO->closeCursor( cursorName );
return false;
}
else if ( rows != 1 )
{
QgsDebugMsg( QString( "found %1 features instead of just one." ).arg( rows ) );
}
bool gotit = getFeature( queryResult, 0, fetchGeometry, feature, fetchAttributes );
connectionRO->closeCursor( cursorName );
return gotit;
}
QgsDataSourceURI& QgsPostgresProvider::getURI()
{
return mUri;
}
void QgsPostgresProvider::setExtent( QgsRectangle& newExtent )
{
layerExtent.setXMaximum( newExtent.xMaximum() );
layerExtent.setXMinimum( newExtent.xMinimum() );
layerExtent.setYMaximum( newExtent.yMaximum() );
layerExtent.setYMinimum( newExtent.yMinimum() );
}
// TODO - make this function return the real extent_
QgsRectangle QgsPostgresProvider::extent()
{
return layerExtent; //extent_->MinX, extent_->MinY, extent_->MaxX, extent_->MaxY);
}
/**
* Return the feature type
*/
QGis::WkbType QgsPostgresProvider::geometryType() const
{
return geomType;
}
/**
* Return the feature type
*/
long QgsPostgresProvider::featureCount() const
{
return featuresCounted;
}
const QgsField &QgsPostgresProvider::field( int index ) const
{
QgsFieldMap::const_iterator it = attributeFields.find( index );
if ( it == attributeFields.constEnd() )
{
QgsDebugMsg( "Field " + QString::number( index ) + " not found." );
throw PGFieldNotFound();
}
return it.value();
}
/**
* Return the number of fields
*/
uint QgsPostgresProvider::fieldCount() const
{
return attributeFields.size();
}
const QgsFieldMap & QgsPostgresProvider::fields() const
{
return attributeFields;
}
QString QgsPostgresProvider::dataComment() const
{
return mDataComment;
}
void QgsPostgresProvider::rewind()
{
if ( mFetching )
{
//move cursor to first record
connectionRO->PQexecNR( QString( "move 0 in qgisf%1" ).arg( providerId ) );
}
mFeatureQueue.empty();
loadFields();
}
/** @todo XXX Perhaps this should be promoted to QgsDataProvider? */
QString QgsPostgresProvider::endianString()
{
switch ( QgsApplication::endian() )
{
case QgsApplication::NDR:
return QString( "NDR" );
break;
case QgsApplication::XDR:
return QString( "XDR" );
break;
default :
return QString( "Unknown" );
}
}
void QgsPostgresProvider::loadFields()
{
QgsDebugMsg( "Loading fields for table " + mTableName );
// Get the relation oid for use in later queries
QString sql = QString( "SELECT regclass(%1)::oid" ).arg( quotedValue( mSchemaTableName ) );
Result tresult = connectionRO->PQexec( sql );
QString tableoid = QString::fromUtf8( PQgetvalue( tresult, 0, 0 ) );
// Get the table description
sql = QString( "SELECT description FROM pg_description WHERE objoid=%1 AND objsubid=0" ).arg( tableoid );
tresult = connectionRO->PQexec( sql );
if ( PQntuples( tresult ) > 0 )
mDataComment = QString::fromUtf8( PQgetvalue( tresult, 0, 0 ) );
// Populate the field vector for this layer. The field vector contains
// field name, type, length, and precision (if numeric)
sql = QString( "select * from %1 limit 0" ).arg( mSchemaTableName );
Result result = connectionRO->PQexec( sql );
// The queries inside this loop could possibly be combined into one
// single query - this would make the code run faster.
attributeFields.clear();
for ( int i = 0; i < PQnfields( result ); i++ )
{
QString fieldName = QString::fromUtf8( PQfname( result, i ) );
int fldtyp = PQftype( result, i );
QString typOid = QString().setNum( fldtyp );
int fieldModifier = PQfmod( result, i );
QString fieldComment( "" );
sql = QString( "SELECT typname,typtype,typelem,typlen FROM pg_type WHERE oid=%1" ).arg( typOid );
// just oid; needs more work to support array type
// "oid = (SELECT Distinct typelem FROM pg_type WHERE " //needs DISTINCT to guard against 2 or more rows on int2
// "typelem = " + typOid + " AND typlen = -1)";
Result oidResult = connectionRO->PQexec( sql );
QString fieldTypeName = QString::fromUtf8( PQgetvalue( oidResult, 0, 0 ) );
QString fieldTType = QString::fromUtf8( PQgetvalue( oidResult, 0, 1 ) );
QString fieldElem = QString::fromUtf8( PQgetvalue( oidResult, 0, 2 ) );
int fieldSize = QString::fromUtf8( PQgetvalue( oidResult, 0, 3 ) ).toInt();
sql = QString( "SELECT attnum FROM pg_attribute WHERE attrelid=%1 AND attname=%2" )
.arg( tableoid ).arg( quotedValue( fieldName ) );
Result tresult = connectionRO->PQexec( sql );
QString attnum = QString::fromUtf8( PQgetvalue( tresult, 0, 0 ) );
sql = QString( "SELECT description FROM pg_description WHERE objoid=%1 AND objsubid=%2" )
.arg( tableoid ).arg( attnum );
tresult = connectionRO->PQexec( sql );
if ( PQntuples( tresult ) > 0 )
fieldComment = QString::fromUtf8( PQgetvalue( tresult, 0, 0 ) );
if ( fieldName != geometryColumn )
{
QVariant::Type fieldType;
if ( fieldTType == "b" )
{
bool isArray = fieldTypeName.startsWith( "_" );
if ( isArray )
fieldTypeName = fieldTypeName.mid( 1 );
if ( fieldTypeName == "int8" )
{
fieldType = QVariant::LongLong;
fieldSize = -1;
}
else if ( fieldTypeName.startsWith( "int" ) ||
fieldTypeName == "serial" )
{
fieldType = QVariant::Int;
fieldSize = -1;
}
else if ( fieldTypeName == "real" ||
fieldTypeName == "double precision" ||
fieldTypeName.startsWith( "float" ) ||
fieldTypeName == "numeric" )
{
fieldType = QVariant::Double;
fieldSize = -1;
}
else if ( fieldTypeName == "text" ||
fieldTypeName == "bpchar" ||
fieldTypeName == "varchar" ||
fieldTypeName == "bool" ||
fieldTypeName == "geometry" ||
fieldTypeName == "money" ||
fieldTypeName.startsWith( "time" ) ||
fieldTypeName.startsWith( "date" ) )
{
fieldType = QVariant::String;
fieldSize = -1;
}
else if ( fieldTypeName == "char" )
{
fieldType = QVariant::String;
}
else
{
QgsDebugMsg( "Field " + fieldName + " ignored, because of unsupported type " + fieldTypeName );
continue;
}
if ( isArray )
{
fieldTypeName = "_" + fieldTypeName;
fieldType = QVariant::String;
fieldSize = -1;
}
}
else if ( fieldTType == "e" )
{
// enum
fieldType = QVariant::String;
fieldSize = -1;
}
else
{
QgsDebugMsg( "Field " + fieldName + " ignored, because of unsupported type type " + fieldTType );
continue;
}
attributeFields.insert( i, QgsField( fieldName, fieldType, fieldTypeName, fieldSize, fieldModifier, fieldComment ) );
}
}
}
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 = QString( "select indkey from pg_index where indisunique and indrelid=regclass(%1)::oid and indpred is null" )
.arg( quotedValue( mSchemaTableName ) );
QgsDebugMsg( "Getting unique index using '" + sql + "'" );
Result pk = connectionRO->PQexec( sql );
QgsDebugMsg( "Got " + QString::number( PQntuples( pk ) ) + " rows." );
QStringList log;
// if we got no tuples we ain't got no unique index :)
if ( PQntuples( pk ) == 0 )
{
QgsDebugMsg( "Relation has no unique index -- investigating alternatives" );
// 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 = QString( "SELECT relkind FROM pg_class WHERE oid=regclass(%1)::oid" )