qgsgrassprovider.cpp

一个非常好的GIS开源新版本

#endif

  dbCursor databaseCursor;
  if ( db_open_select_cursor(driver, &dbstr, &databaseCursor, DB_SCROLL) != DB_OK ){
    db_close_database_shutdown_driver ( driver );
    std::cerr << "Cannot select attributes from table" << std::endl;
    return att;
  } 

  int nRecords = db_get_num_rows ( &databaseCursor );
#ifdef QGISDEBUG
  std::cerr << "Number of records: " << nRecords << std::endl;
#endif

  if ( nRecords < 1 ) {
    db_close_database_shutdown_driver ( driver );
    std::cerr << "No DB record" << std::endl;
    return att;
  }

  dbTable  *databaseTable = db_get_cursor_table (&databaseCursor);
  int nColumns = db_get_table_number_of_columns(databaseTable);

  int more;
  if ( db_fetch (&databaseCursor, DB_NEXT, &more) != DB_OK ) {
    db_close_database_shutdown_driver ( driver );
    std::cout << "Cannot fetch DB record" << std::endl;
    return att;
  }

  // Read columns' description 
  for (int i = 0; i < nColumns; i++) {
    dbColumn *column = db_get_table_column (databaseTable, i);
    db_convert_column_value_to_string (column, &dbstr);

    QString v = mEncoding->toUnicode(db_get_string(&dbstr));
    std::cerr << "Value: " << v.toLocal8Bit().data() << std::endl;
    att->insert(i, QVariant( v ) );
  }

  db_close_cursor (&databaseCursor);
  db_close_database_shutdown_driver ( driver );
  db_free_string(&dbstr);

  return att;
}

QString *QgsGrassProvider::updateAttributes ( int field, int cat, const QString &values )
{
#ifdef QGISDEBUG
  std::cerr << "QgsGrassProvider::updateAttributes() field = " << field << " cat = " << cat << std::endl;
#endif

  QString *error = new QString();
  struct  field_info *fi = Vect_get_field( mMap, field); // should work also with field = 0

  // Read attributes
  if ( fi == NULL ) {
#ifdef QGISDEBUG
    std::cerr << "No field info -> no attributes" << std::endl;
#endif
    error->setLatin1( "Cannot get field info" );
    return error;
  }

#ifdef QGISDEBUG
  std::cerr << "Field info found -> open database" << std::endl;
#endif
  QgsGrass::setMapset ( mGisdbase, mLocation, mMapset ); 
  dbDriver *driver = db_start_driver_open_database ( fi->driver, fi->database );

  if ( driver == NULL ) {
    std::cerr << "Cannot open database " << fi->database << " by driver " << fi->driver << std::endl;
    error->setAscii("Cannot open database");
    return error;
  }

#ifdef QGISDEBUG
  std::cerr << "Database opened -> read attributes" << std::endl;
#endif

  dbString dbstr; 
  db_init_string (&dbstr);
  QString query;

  query = "update " + QString(fi->table) + " set " + values + " where " + QString(fi->key) 
    + " = " + QString::number(cat);

#ifdef QGISDEBUG
  std::cerr << "query: " << query.toLocal8Bit().data() << std::endl;
#endif

  // For some strange reason, mEncoding->fromUnicode(query) does not work, 
  // but probably it is not correct, because Qt widgets will use current locales for input
  //  -> it is possible to edit only in current locales at present
  // QCString qcs = mEncoding->fromUnicode(query);

  Q3CString qcs = query.toLocal8Bit().data();
#ifdef QGISDEBUG
  std::cerr << "qcs: " << qcs.data() << std::endl;
#endif

  char *cs = new char[qcs.length() + 1];
  strcpy(cs, (const char *)qcs);
  db_set_string (&dbstr, cs );
  delete[] cs;

#ifdef QGISDEBUG
  std::cerr << "SQL: " << db_get_string(&dbstr) << std::endl;
#endif

  int ret = db_execute_immediate (driver, &dbstr);

  if ( ret != DB_OK) { 
    std::cerr << "Error: " <<  db_get_error_msg() << std::endl;
    error->setLatin1( db_get_error_msg() );
  }

  db_close_database_shutdown_driver ( driver );
  db_free_string(&dbstr);

  return error;
}

int QgsGrassProvider::numDbLinks ( void )
{
#ifdef QGISDEBUG
  std::cerr << "QgsGrassProvider::numDbLinks()" << std::endl;
#endif

  return ( Vect_get_num_dblinks(mMap) );
}

int QgsGrassProvider::dbLinkField ( int link )
{
#ifdef QGISDEBUG
  std::cerr << "QgsGrassProvider::dbLinkField()" << std::endl;
#endif

  struct  field_info *fi = Vect_get_dblink ( mMap, link );

  if ( fi == NULL ) return 0;

  return ( fi->number );
}

QString *QgsGrassProvider::executeSql ( int field, const QString &sql )
{
#ifdef QGISDEBUG
  std::cerr << "QgsGrassProvider::executeSql field = " << field << std::endl;
#endif

  QString *error = new QString();
  struct  field_info *fi = Vect_get_field( mMap, field); // should work also with field = 0

  // Read attributes
  if ( fi == NULL ) {
#ifdef QGISDEBUG
    std::cerr << "No field info -> no attributes" << std::endl;
#endif
    error->setLatin1( "Cannot get field info" );
    return error;
  }

#ifdef QGISDEBUG
  std::cerr << "Field info found -> open database" << std::endl;
#endif

  QgsGrass::setMapset ( mGisdbase, mLocation, mMapset ); 
  dbDriver *driver = db_start_driver_open_database ( fi->driver, fi->database );

  if ( driver == NULL ) {
    std::cerr << "Cannot open database " << fi->database << " by driver " << fi->driver << std::endl;
    error->setAscii("Cannot open database");
    return error;
  }

#ifdef QGISDEBUG
  std::cerr << "Database opened" << std::endl;
#endif

  dbString dbstr; 
  db_init_string (&dbstr);
  db_set_string (&dbstr, (char *)sql.latin1());

#ifdef QGISDEBUG
  std::cerr << "SQL: " << db_get_string(&dbstr) << std::endl;
#endif

  int ret = db_execute_immediate (driver, &dbstr);

  if ( ret != DB_OK) { 
    std::cerr << "Error: " <<  db_get_error_msg() << std::endl;
    error->setLatin1( db_get_error_msg() );
  }

  db_close_database_shutdown_driver ( driver );
  db_free_string(&dbstr);

  return error;

}

QString *QgsGrassProvider::createTable ( int field, const QString &key, const QString &columns )
{
#ifdef QGISDEBUG
  std::cerr << "QgsGrassProvider::createTable() field = " << field << std::endl;
#endif

  QString *error = new QString();
  struct  field_info *fi = Vect_get_field( mMap, field); // should work also with field = 0

  // Read attributes
  if ( fi != NULL ) {
#ifdef QGISDEBUG
    std::cerr << "The table for this field already exists" << std::endl;
#endif
    error->setLatin1( "The table for this field already exists" );
    return error;
  }

#ifdef QGISDEBUG
  std::cerr << "Field info not found -> create new table" << std::endl;
#endif

  // We must set mapset before Vect_default_field_info
  QgsGrass::setMapset ( mGisdbase, mLocation, mMapset ); 

  int nLinks = Vect_get_num_dblinks( mMap );
  if ( nLinks == 0 ) {
    fi = Vect_default_field_info ( mMap, field, NULL, GV_1TABLE );
  } else {
    fi = Vect_default_field_info ( mMap, field, NULL, GV_MTABLE );
  }

  dbDriver *driver = db_start_driver_open_database ( fi->driver, fi->database );

  if ( driver == NULL ) {
    std::cerr << "Cannot open database " << fi->database << " by driver " << fi->driver << std::endl;
    error->setAscii("Cannot open database");
    return error;
  }

#ifdef QGISDEBUG
  std::cerr << "Database opened -> create table" << std::endl;
#endif

  dbString dbstr; 
  db_init_string (&dbstr);
  QString query;

  query.sprintf("create table %s ( %s )", fi->table, columns.latin1() );
  db_set_string (&dbstr, (char *)query.latin1());

#ifdef QGISDEBUG
  std::cerr << "SQL: " << db_get_string(&dbstr) << std::endl;
#endif

  int ret = db_execute_immediate (driver, &dbstr);

  if ( ret != DB_OK) { 
    std::cerr << "Error: " <<  db_get_error_msg() << std::endl;
    error->setLatin1( db_get_error_msg() );
  }

  db_close_database_shutdown_driver ( driver );
  db_free_string(&dbstr);

  if ( !error->isEmpty() ) return error;

  ret = Vect_map_add_dblink ( mMap, field, NULL, fi->table, (char *)key.latin1(), 
    fi->database, fi->driver);

  if ( ret == -1 ) { 
    std::cerr << "Error: Cannot add dblink" << std::endl;
    error->setLatin1( "Cannot create link to the table. The table was created!" );
  }

  return error;
}

QString *QgsGrassProvider::addColumn ( int field, const QString &column )
{
#ifdef QGISDEBUG
  std::cerr << "QgsGrassProvider::addColumn() field = " << field << std::endl;
#endif

  QString *error = new QString();
  struct  field_info *fi = Vect_get_field( mMap, field); // should work also with field = 0

  // Read attributes
  if ( fi == NULL ) {
#ifdef QGISDEBUG
    std::cerr << "No field info" << std::endl;
#endif
    error->setLatin1( "Cannot get field info" );
    return error;
  }

  QString query;

  query.sprintf("alter table %s add column %s", fi->table, column.latin1() );

  delete error;
  return executeSql ( field, query );
}

QString *QgsGrassProvider::insertAttributes ( int field, int cat )
{
#ifdef QGISDEBUG
  std::cerr << "QgsGrassProvider::insertAttributes() field = " << field << " cat = " << cat << std::endl;
#endif

  QString *error = new QString();
  struct  field_info *fi = Vect_get_field( mMap, field); // should work also with field = 0

  // Read attributes
  if ( fi == NULL ) {
#ifdef QGISDEBUG
    std::cerr << "No field info -> no attributes" << std::endl;
#endif
    error->setLatin1( "Cannot get field info" );
    return error;
  }

  QString query;

  query.sprintf("insert into %s ( %s ) values ( %d )", fi->table, fi->key, cat );

  delete error;
  return executeSql ( field, query );
}

QString *QgsGrassProvider::deleteAttributes ( int field, int cat )
{
#ifdef QGISDEBUG
  std::cerr << "QgsGrassProvider::deleteAttributes() field = " << field << " cat = " << cat << std::endl;
#endif

  QString *error = new QString();
  struct  field_info *fi = Vect_get_field( mMap, field); // should work also with field = 0

  // Read attributes
  if ( fi == NULL ) {
#ifdef QGISDEBUG
    std::cerr << "No field info -> no attributes" << std::endl;
#endif
    error->setLatin1( "Cannot get field info" );
    return error;
  }

  QString query;

  query.sprintf("delete from %s where %s = %d", fi->table, fi->key, cat );

  delete error;
  return executeSql ( field, query );
}

QString *QgsGrassProvider::isOrphan ( int field, int cat, int *orphan)
{
#ifdef QGISDEBUG
  std::cerr << "QgsGrassProvider::isOrphan() field = " << field << " cat = " << cat << std::endl;
#endif

  QString *error = new QString();

  // Check first if another line with such cat exists
  int fieldIndex = Vect_cidx_get_field_index ( mMap, field );
  if ( fieldIndex >= 0 ) 
  {
    int t, id;
    int ret = Vect_cidx_find_next ( mMap, fieldIndex, cat, 
      GV_POINTS|GV_LINES, 0, &t, &id );

    if ( ret >= 0 ) {
      // Category exists
      *orphan = false;
      return error; 
    }
  }

  // Check if attribute exists
  struct  field_info *fi = Vect_get_field( mMap, field); // should work also with field = 0

  // Read attributes
  if ( fi == NULL ) {
#ifdef QGISDEBUG
    std::cerr << "No field info -> no attributes" << std::endl;
#endif
    *orphan = false;
    return error; 
  }

#ifdef QGISDEBUG
  std::cerr << "Field info found -> open database" << std::endl;
#endif
  QgsGrass::setMapset ( mGisdbase, mLocation, mMapset ); 
  dbDriver *driver = db_start_driver_open_database ( fi->driver, fi->database );

  if ( driver == NULL ) {
    std::cerr << "Cannot open database " << fi->database << " by driver " << fi->driver << std::endl;
    error->setAscii("Cannot open database");
    return error;
  }

#ifdef QGISDEBUG
  std::cerr << "Database opened -> select record" << std::endl;
#endif

  dbString dbstr; 
  db_init_string (&dbstr);
  QString query;

  query.sprintf("select %s from %s where %s = %d", fi->key, fi->table, fi->key, cat );
  db_set_string (&dbstr, (char *)query.latin1());

#ifdef QGISDEBUG
  std::cerr << "SQL: " << db_get_string(&dbstr) << std::endl;
#endif

  dbCursor cursor;
  if ( db_open_select_cursor(driver, &dbstr, &cursor, DB_SCROLL) != DB_OK )
  {
    db_close_database_shutdown_driver ( driver );
    error->setAscii("Cannot query database: " + query );
    return error;
  }
  int nRecords = db_get_num_rows ( &cursor );
#ifdef QGISDEBUG
  std::cerr << "Number of records: " << nRecords << std::endl;
#endif

  if ( nRecords > 0 ) { *orphan = true; }

  db_close_database_shutdown_driver ( driver );
  db_free_string(&dbstr);

  return error;
}


// -------------------------------------------------------------------------------

int QgsGrassProvider::cidxGetNumFields( ) 
{
  return ( Vect_cidx_get_num_fields(mMap) );
}

int QgsGrassProvider::cidxGetFieldNumber( int idx ) 
{
  return ( Vect_cidx_get_field_number(mMap, idx) );
}

int QgsGrassProvider::cidxGetMaxCat( int idx ) 
{
  int ncats = Vect_cidx_get_num_cats_by_index ( mMap, idx);

  int cat, type, id;
  Vect_cidx_get_cat_by_index ( mMap, idx, ncats-1, &cat, &type, &id );

  return ( cat );
}
    


QString QgsGrassProvider::name() const
{
  return GRASS_KEY;
} // QgsGrassProvider::name()



QString QgsGrassProvider::description() const
{
  return GRASS_DESCRIPTION;
} // QgsGrassProvider::description()