Data Management
Detailed Information About the JGOFS Distributed Database Management System (DDMS)
Examples of Selection
Selection -- choosing to display information only when particular
variables satisfy specified criteria -- is accomplished by including a
Boolean combination of comparisons as an argument to the data object.
objectname(variablename1=value1&variablename2=value2...)
Permissable comparison operators are
<,=,>,<=,*<>,>=
while the Boolean operations are
&(and),|(or),!(not)
and grouping is accomplished with left and right parentheses. As an example we show some subselected data sets:
Thus if we have a data object hyd (displayed by the programlist)
list "hyd"
# wunsch stations 3-5
# p<1000
=======================
leg, year, month
........................ [lowest (0) level data]
1, 81, 6
=======================
station, lat, lon
........................ [first level data]
3, 38.28, -73.53
=======================
press, temp, sal, o2, sigth
------------------------
5.000, 18.334, 33.570, 5.970, 24.096
25.000, 12.848, 34.159, 6.990, 25.773
49.000, 11.070, 34.523, 6.060, 26.394 [second level]
99.000, 11.093, 35.090, 5.340, 26.831
149.000, 11.906, 35.487, 5.020, 26.990
199.000, 10.819, 35.435, 4.210, 27.152
300.000, 8.293, 35.126, 3.730, 27.334
400.000, 6.363, 35.046, 4.640, 27.546
500.000, 5.724, 35.019, 4.980, 27.608
600.000, 5.031, 34.990, 5.460, 27.670
701.000, 4.633, 34.981, 5.680, 27.710
801.000, 4.515, 34.980, 5.850, 27.722
901.000, 4.376, 34.979, 5.880, 27.737
=======================
station, lat, lon
........................
4, 38.19, -73.52
=======================
press, temp, sal, o2, sigth
------------------------
5.000, 17.516, 33.160, 5.840, 23.981
25.000, 12.315, 33.958, 7.090, 25.721
49.000, 9.612, 34.192, 6.020, 26.387
99.000, 12.095, 35.402, 5.340, 26.887
149.000, 12.407, 35.625, 5.290, 27.000
199.000, 11.287, 35.487, 4.340, 27.108
300.000, 8.059, 35.120, 3.750, 27.365
400.000, 6.606, 35.053, 4.440, 27.520
500.000, 5.467, 34.997, 5.130, 27.622
600.000, 5.003, 34.983, 5.460, 27.667
701.000, 4.680, 34.979, 5.700, 27.702
801.000, 4.489, 34.977, 5.850, 27.722
901.000, 4.374, 34.978, 5.930, 27.737
=======================
station, lat, lon
........................
5, 38.16, -73.26
=======================
press, temp, sal, o2, sigth
------------------------
5.000, 18.382, 33.647, 5.770, 24.143
25.000, 12.040, 34.196, 6.660, 25.959
49.000, 11.951, 34.925, 5.510, 26.543
99.000, 11.914, 35.390, 5.100, 26.912
149.000, 12.045, 35.547, 5.070, 27.010
199.000, 11.976, 35.589, 4.940, 27.057
300.000, 9.425, 35.250, 3.620, 27.251
400.000, 7.003, 35.075, 4.210, 27.483
500.000, 5.827, 35.009, 4.910, 27.589
600.000, 5.252, 34.988, 5.300, 27.643
701.000, 4.845, 34.980, 5.610, 27.684
801.000, 4.635, 34.980, 5.710, 27.709
901.000, 4.444, 34.978, 5.940, 27.729
****** End of object ***
we can select a depth range by
list "hyd(press<=500)"
# wunsch stations 3-5
# p<1000
=======================
leg, year, month
........................
1, 81, 6
=======================
station, lat, lon
........................
3, 38.28, -73.53
=======================
press, temp, sal, o2, sigth
------------------------
5.000, 18.334, 33.570, 5.970, 24.096
25.000, 12.848, 34.159, 6.990, 25.773
49.000, 11.070, 34.523, 6.060, 26.394
99.000, 11.093, 35.090, 5.340, 26.831
149.000, 11.906, 35.487, 5.020, 26.990
199.000, 10.819, 35.435, 4.210, 27.152
300.000, 8.293, 35.126, 3.730, 27.334
400.000, 6.363, 35.046, 4.640, 27.546
500.000, 5.724, 35.019, 4.980, 27.608
=======================
station, lat, lon
........................
4, 38.19, -73.52
=======================
press, temp, sal, o2, sigth
------------------------
5.000, 17.516, 33.160, 5.840, 23.981
25.000, 12.315, 33.958, 7.090, 25.721
49.000, 9.612, 34.192, 6.020, 26.387
99.000, 12.095, 35.402, 5.340, 26.887
149.000, 12.407, 35.625, 5.290, 27.000
199.000, 11.287, 35.487, 4.340, 27.108
300.000, 8.059, 35.120, 3.750, 27.365
400.000, 6.606, 35.053, 4.440, 27.520
500.000, 5.467, 34.997, 5.130, 27.622
=======================
station, lat, lon
........................
5, 38.16, -73.26
=======================
press, temp, sal, o2, sigth
------------------------
5.000, 18.382, 33.647, 5.770, 24.143
25.000, 12.040, 34.196, 6.660, 25.959
49.000, 11.951, 34.925, 5.510, 26.543
99.000, 11.914, 35.390, 5.100, 26.912
149.000, 12.045, 35.547, 5.070, 27.010
199.000, 11.976, 35.589, 4.940, 27.057
300.000, 9.425, 35.250, 3.620, 27.251
400.000, 7.003, 35.075, 4.210, 27.483
500.000, 5.827, 35.009, 4.910, 27.589
****** End of object ***
or a particular station by
list "hyd(station=4)"
# wunsch stations 3-5
# p<1000
=======================
leg, year, month
........................
1, 81, 6
=======================
station, lat, lon
........................
4, 38.19, -73.52
=======================
press, temp, sal, o2, sigth
------------------------
5.000, 17.516, 33.160, 5.840, 23.981
25.000, 12.315, 33.958, 7.090, 25.721
49.000, 9.612, 34.192, 6.020, 26.387
99.000, 12.095, 35.402, 5.340, 26.887
149.000, 12.407, 35.625, 5.290, 27.000
199.000, 11.287, 35.487, 4.340, 27.108
300.000, 8.059, 35.120, 3.750, 27.365
400.000, 6.606, 35.053, 4.440, 27.520
500.000, 5.467, 34.997, 5.130, 27.622
600.000, 5.003, 34.983, 5.460, 27.667
701.000, 4.680, 34.979, 5.700, 27.702
801.000, 4.489, 34.977, 5.850, 27.722
901.000, 4.374, 34.978, 5.930, 27.737
****** End of object ***
or combine these operations
list "hyd(station=4&press<=500)"
# wunsch stations 3-5
# p<1000
=======================
leg, year, month
........................
1, 81, 6
=======================
station, lat, lon
........................
4, 38.19, -73.52
=======================
press, temp, sal, o2, sigth
------------------------
5.000, 17.516, 33.160, 5.840, 23.981
25.000, 12.315, 33.958, 7.090, 25.721
49.000, 9.612, 34.192, 6.020, 26.387
99.000, 12.095, 35.402, 5.340, 26.887
149.000, 12.407, 35.625, 5.290, 27.000
199.000, 11.287, 35.487, 4.340, 27.108
300.000, 8.059, 35.120, 3.750, 27.365
400.000, 6.606, 35.053, 4.440, 27.520
500.000, 5.467, 34.997, 5.130, 27.622
****** End of object ***
A more complex selection might look like
list "hyd((station=4|station=5)&press>=200&press<=500)"
# wunsch stations 3-10
# p<1000
=======================
leg, year, month
........................
1, 81, 6
=======================
station, lat, lon
........................
4, 38.19, -73.52
=======================
press, temp, sal, o2, sigth
------------------------
300.000, 8.059, 35.120, 3.750, 27.365
400.000, 6.606, 35.053, 4.440, 27.520
500.000, 5.467, 34.997, 5.130, 27.622
=======================
station, lat, lon
........................
5, 38.16, -73.26
=======================
press, temp, sal, o2, sigth
------------------------
300.000, 9.425, 35.250, 3.620, 27.251
400.000, 7.003, 35.075, 4.210, 27.483
500.000, 5.827, 35.009, 4.910, 27.589
****** End of object ***
Projection can be combined with selection by adding the list of
variables to be returned also.
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