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Capture a few unusual occurences with respect to views with unique

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constraints but non-unique data. In response to ticket #143.


git-svn-id: http://svn.osgeo.org/qgis/trunk@5514 c8812cc2-4d05-0410-92ff-de0c093fc19c
This commit is contained in:
g_j_m 2006-06-11 09:43:00 +00:00
parent 5980feaf48
commit 7eb8a7c86e
1 changed files with 54 additions and 55 deletions
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109
src/providers/postgres/qgspostgresprovider.cpp
View File

@ -1167,70 +1167,69 @@ QString QgsPostgresProvider::chooseViewColumn(const tableCols& cols)
// indexed, else pick one called 'oid' if it exists, else
// pick the first one. If there are none we return an empty string.
if (suitable.size() == 1)
// Search for one with an index
tableCols::const_iterator i = suitable.begin();
for (; i != suitable.end(); ++i)
{
if (uniqueData(mSchemaName, mTableName, suitable.begin()->first))
// Get the relation oid from our cache.
QString rel_oid = relOid[i->first];
// And see if the column has an index
sql = "select * from pg_index where indrelid = " + rel_oid +
" and indkey[0] = (select attnum from pg_attribute where "
"attrelid = " + rel_oid + " and attname = '" + i->second.column + "')";
PGresult* result = PQexec(connection, (const char*)(sql.utf8()));
if (PQntuples(result) > 0 && uniqueData(mSchemaName, mTableName, i->first))
{ // Got one. Use it.
key = i->first;
#ifdef QGISDEBUG
std::cerr << "Picked column '" << key.toLocal8Bit().data()
<< "' because it has an index.\n";
#endif
break;
}
PQclear(result);
}
if (key.isEmpty())
{
// If none have indices, choose one that is called 'oid' (if it
// exists). This is legacy support and could be removed in
// future.
i = suitable.find("oid");
if (i != suitable.end() && uniqueData(mSchemaName, mTableName, i->first))
{
key = suitable.begin()->first;
key = i->first;
#ifdef QGISDEBUG
std::cerr << "Picked column " << key.toLocal8Bit().data()
<< " as it is the only one that was suitable.\n";
<< " as it is probably the postgresql object id "
<< " column (which contains unique values) and there are no"
<< " columns with indices to choose from\n.";
#endif
}
}
else if (suitable.size() > 1)
{
// Search for one with an index
tableCols::const_iterator i = suitable.begin();
for (; i != suitable.end(); ++i)
// else choose the first one in the container that has unique data
else
{
// Get the relation oid from our cache.
QString rel_oid = relOid[i->first];
// And see if the column has an index
sql = "select * from pg_index where indrelid = " + rel_oid +
" and indkey[0] = (select attnum from pg_attribute where "
"attrelid = " + rel_oid + " and attname = '" + i->second.column + "')";
PGresult* result = PQexec(connection, (const char*)(sql.utf8()));
if (PQntuples(result) > 0 && uniqueData(mSchemaName, mTableName, i->first))
{ // Got one. Use it.
key = i->first;
#ifdef QGISDEBUG
std::cerr << "Picked column '" << key.toLocal8Bit().data()
<< "' because it has an index.\n";
#endif
break;
}
PQclear(result);
}
if (key.isEmpty())
{
// If none have indices, choose one that is called 'oid' (if it
// exists). This is legacy support and could be removed in
// future.
i = suitable.find("oid");
if (i != suitable.end() && uniqueData(mSchemaName, mTableName, i->first))
tableCols::const_iterator i = suitable.begin();
for (; i != suitable.end(); ++i)
{
key = i->first;
if (uniqueData(mSchemaName, mTableName, i->first))
{
key = i->first;
#ifdef QGISDEBUG
std::cerr << "Picked column " << key.toLocal8Bit().data()
<< " as it is probably the postgresql object id "
<< " column (which contains unique values) and there are no"
<< " columns with indices to choose from\n.";
#endif
}
// else choose the first one in the container, ensuring that it
// contains unique data
else if (uniqueData(mSchemaName, mTableName, suitable.begin()->first))
{
key = suitable.begin()->first;
#ifdef QGISDEBUG
std::cerr << "Picked column " << key.toLocal8Bit().data()
<< " as it was the first suitable column found"
<< " and there are no"
<< " columns with indices to choose from\n.";
std::cerr << "Picked column " << key.toLocal8Bit().data()
<< " as it was the first suitable column found"
<< " with unique data and were are no"
<< " columns with indices to choose from\n.";
#endif
break;
}
else
{
log << QString(tr("Note: ") + "'" + key + "'"
+ tr("initially appeared suitable but does not "
"contain unique data, so is not suitable.\n"));
}
}
}
}
@ -1248,7 +1247,7 @@ QString QgsPostgresProvider::chooseViewColumn(const tableCols& cols)
"have a unique constraint on it, or be a PostgreSQL "
"oid column. To improve "
"performance the column should also be indexed.\n"));
log.prepend(tr("The view ") + "'" + mSchemaName + mTableName + "'" +
log.prepend(tr("The view ") + "'" + mSchemaName + '.' + mTableName + "' " +
tr("has no column suitable for use as a unique key.\n"));
showMessageBox(tr("No suitable key column in view"), log);
}