Definition and listing of LUT (Look-up Tables)

Look-up Tables are an important features of a good data base design. Typically they are small tables, which contain parameter codes and general values.

Altogether, the Irrigation module uses the following Look-up Tables (sorted alphabetically):

Table name Notes Database location Online /offline
AGENCIES Agencies operating monitoring networks internal -
Hyyear Relation of calendar months to months of the hydrological year internal -
IRRIGATION_METHOD 3 different irrigation technologies internal -
MAIN_CROP_GROUP 10 Main crop groups internal -
Perennials Property for main crop groups internal -
Projections projection years 2005 ... 2040 internal -
Ref_year Reference years for agricultural statistics, 1994 - 2000 internal -
Salinity Class internal -
Scenarios 3 alternative planning scenarios internal -
Y_Type dry, median, wet year types internal -

N.B. Internal means, that the table is not linked from an external database but that it is built-in the irrigation module.

For example, the LUT for salinities looks as follows:

Table Salinity_Class TDS (total dissolved solids) in mg/l

1 Salinity Class 1 0 1000 Good for Drinking & generally no restriction in irrgtn
2 Salinity Class 2 1000 2000 Slight to moderate restriction on irrgtn use
3 Salinity Class 3 2000 2800 Severe restriction on irrgtn use, only for special crops
4 Salinity Class 4 2800 50000 Usable only after desalination
0 no Leaching 0 0 No consideration of salinity

In the corresponding tables (particularly the STP tables), only the entry of the salinity class field [S_CLASS] is used. If salinity classes are to be redefined, it would be sufficient just to modify the Look-up table.