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+ initial support for 'SELECT' statements in <table> param.

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+ use limit 0 to avoid lengthy queries (does it work ?)
This commit is contained in:
Artem Pavlenko 2009-02-23 22:13:21 +00:00
parent 4de010b840
commit f4f1cd4c59
1 changed files with 57 additions and 15 deletions
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72
plugins/input/sqlite/sqlite_datasource.cpp
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@ -52,6 +52,29 @@ using mapnik::attribute_descriptor;
using mapnik::datasource_exception;
std::string table_from_sql(std::string const& sql)
{
std::string table_name = boost::algorithm::to_lower_copy(sql);
boost::algorithm::replace_all(table_name,"\n"," ");
std::string::size_type idx = table_name.rfind("from");
if (idx!=std::string::npos)
{
idx=table_name.find_first_not_of(" ",idx+4);
if (idx != std::string::npos)
{
table_name=table_name.substr(idx);
}
idx=table_name.find_first_of(" ),");
if (idx != std::string::npos)
{
table_name = table_name.substr(0,idx);
}
}
return table_name;
}
sqlite_datasource::sqlite_datasource(parameters const& params)
: datasource(params),
extent_(),
@ -115,12 +138,14 @@ sqlite_datasource::sqlite_datasource(parameters const& params)
extent_initialized_ = true;
}
}
std::string table_name = table_from_sql(table_);
if (metadata_ != "" && ! extent_initialized_)
{
std::ostringstream s;
s << "select xmin, ymin, xmax, ymax from " << metadata_;
s << " where lower(f_table_name) = lower('" << table_ << "')";
s << " where lower(f_table_name) = lower('" << table_name << "')";
boost::scoped_ptr<sqlite_resultset> rs (dataset_->execute_query (s.str()));
if (rs->is_valid () && rs->step_next())
{
@ -147,10 +172,10 @@ sqlite_datasource::sqlite_datasource(parameters const& params)
#ifdef MAPNIK_DEBUG
if (! use_spatial_index_)
clog << "cannot use the spatial index " << endl;
clog << "cannot use the spatial index " << endl;
#endif
}
{
/*
XXX - This is problematic, if we don't have at least a row,
@ -158,7 +183,7 @@ sqlite_datasource::sqlite_datasource(parameters const& params)
as all column_type are SQLITE_NULL
*/
std::ostringstream s;
s << "select * from " << table_ << " limit 1";
s << "select * from " << table_ << " limit 0";
boost::scoped_ptr<sqlite_resultset> rs (dataset_->execute_query (s.str()));
if (rs->is_valid () && rs->step_next())
{
@ -229,6 +254,7 @@ featureset_ptr sqlite_datasource::features(query const& q) const
mapnik::Envelope<double> const& e = q.get_bbox();
std::ostringstream s;
s << "select " << geometry_field_ << "," << key_field_;
std::set<std::string> const& props = q.property_names();
std::set<std::string>::const_iterator pos = props.begin();
@ -237,17 +263,33 @@ featureset_ptr sqlite_datasource::features(query const& q) const
{
s << "," << *pos << "";
++pos;
}
s << " from " << table_;
}
s << " from ";
std::string query (table_);
if (use_spatial_index_)
{
s << std::setprecision(16);
s << " where rowid in (select pkid from idx_" << table_ << "_" << geometry_field_;
s << " where xmax>=" << e.minx() << " and xmin<=" << e.maxx() ;
s << " and ymax>=" << e.miny() << " and ymin<=" << e.maxy() << ")";
std::string table_name = table_from_sql(query);
std::ostringstream spatial_sql;
spatial_sql << std::setprecision(16);
spatial_sql << " where rowid in (select pkid from idx_" << table_name << "_" << geometry_field_;
spatial_sql << " where xmax>=" << e.minx() << " and xmin<=" << e.maxx() ;
spatial_sql << " and ymax>=" << e.miny() << " and ymin<=" << e.maxy() << ")";
if (boost::algorithm::ifind_first(query,"where"))
{
boost::algorithm::ireplace_first(query, "where", spatial_sql.str() + " and");
}
else if (boost::algorithm::find_first(query,table_name))
{
boost::algorithm::ireplace_first(query, table_name , table_name + " " + spatial_sql.str());
}
}
s << query ;
if (row_limit_ > 0) {
s << " limit " << row_limit_;
}
@ -256,9 +298,9 @@ featureset_ptr sqlite_datasource::features(query const& q) const
s << " offset " << row_offset_;
}
//#ifdef MAPNIK_DEBUG
#ifdef MAPNIK_DEBUG
std::cerr << s.str() << "\n";
//#endif
#endif
boost::shared_ptr<sqlite_resultset> rs (dataset_->execute_query (s.str()));