Oracle Coordinate System Transformation Functions

-- how to extract srids
SELECT *
FROM mdsys.cs_srs cs
WHERE cs.cs_name LIKE '%UTM%'
AND cs.cs_name LIKE '%32%';

-- how to make a spatial point (WGS84)
SELECT mdsys.sdo_geometry(2001, 8307, mdsys.sdo_point_type(n.x, n.y, NULL), NULL, NULL) AS geometry
FROM nodes n;

-- how to make a converted spatial point (UTM Zone 32, Northern Hemisphere (WGS 84))
SELECT t.geometry.sdo_point.x as x, t.geometry.sdo_point.y as y FROM (SELECT sdo_cs.transform(mdsys.sdo_geometry(2001, 8307, mdsys.sdo_point_type(n.x, n.y, NULL), NULL, NULL), 82344) AS geometry FROM nodes n) t;

82344 is SRID for UTM Zone 32, Northern Hemisphere (WGS 84).

Polymorphism

// abstract base class
#include 
using namespace std;

class CPolygon {
protected:
int width, height;
public:
void set_values (int a, int b)
  { width=a; height=b; }
virtual int area (void) =0;
};

class CRectangle: public CPolygon {
public:
int area (void)
  { return (width * height); }
};

class CTriangle: public CPolygon {
public:
int area (void)
  { return (width * height / 2); }
};

int main () {
CRectangle rect;
CTriangle trgl;
CPolygon * ppoly1 = ▭
CPolygon * ppoly2 = &trgl;
ppoly1->set_values (4,5);
ppoly2->set_values (4,5);
ppoly1->area();
ppoly2->area();
return 0;
}

Abstract Class vs. Interface

Abstract Class: can have non-abstract method; can have member variables; all the abstract methods must be overwritten in the extended classes.

Interface: describe some common rules, thus all methods are abstract; all member variables must be final static; In java, interface can be used for multi-inheritance purpose.

Geodetic coordinates translation - useful links

http://psas.pdx.edu/CoordinateSystem/Latitude_to_LocalTangent.pdf

http://en.wikipedia.org/wiki/Geodetic_system

http://www.cplusplus.com/reference/clibrary/cmath/

IMP and EXP with data pump

$ expdp hr/hr DIRECTORY=exp_dir DUMPFILE=hr_exp.dmp LOGFILE=hr_exp.log

$ CREATE DIRECTORY dir_dump AS 'D:/tmp'

create user hr2

$ GRANT READ, WRITE ON DIRECTORY dir_dump TO hr2

$ impdp hr2/hr2 SCHEMAS=hr2 DIRECTORY=dir_dump LOGFILE=hr2_imp.log DUMPFILE=hr_exp.dmp

"case" in SQL

UPDATE inventory SET price = price *
 CASE
   WHEN quantity > 20 THEN 0.75
   WHEN quantity BETWEEN 10 AND 20 THEN 0.90
   ELSE 0.95
   END;

SELECT employee_name
 CASE admin
   WHEN 1 THEN 'yes'
   ELSE 'no'
   END 'admin'
FROM employees;

VC++ project configuration tips

1. use "local setting" files (*.vsprops) to store the directory configurations. It can be reused for more than one projects.

ProjectType="Visual C++"
Version="8.00"
Name="lokale Einstellungen"
>
Name="OcciDir"
Value="D:\apps\oracle10g\OCI"
PerformEnvironmentSet="true"
/>
Name="BoostDir"
Value="D:\boost\Boost\include\boost_1_35_0"
PerformEnvironmentSet="true"
/>
Name="OcciLib"
Value="lib\MSVC\vc8"
PerformEnvironmentSet="true"
/>


2. The includes files' path should be in "C/C++ => Allgemein => Zusaetzliche Includeverzeichnisse".

3. The libs which are needed should be in "Linker => Allgemein => Zusaetzliche Bibliotheksverzeichnisse". If the libs can not be found, there will be errors like "fatal error LNK1104: Datei libboost_program_options-vc80-mt-1_35.lib kann nicht geoeffnet werden".