Rdb: Ruby-Nachbau der MWC /rdb-Werkzeuge

man/validate.man

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+.TH validate "" "" "/rdb Command"
+.PC "Find invalid data"
+\fBvalidate  '\fIpattern \fB{ \fIaction \fB} ...' < \fItableorlist\fR
+.PP
+.II "table^validate"
+.II "data^validate"
+The command
+.B validate
+checks your tables and a list of invalid data.
+It also prints messages of your choosing, and shows
+you the line that caused the error.
+It is almost identical to a combination of the commands
+.B row
+and
+.BR compute .
+.PP
+.B validate
+passes your commands to
+.B awk
+after it has converted your column names to
+.BR $1 ,
+.BR $2 ,
+and so on, which is how
+.B awk
+refers to columns.
+.PP
+.I pattern
+is a logical condition that indicates invalidity in the data;
+for example, it may give values that are negative and should not be,
+or greater than they should be.
+.I action
+is what to do about it;
+usually, this is to print a message.
+.SH Example
+The first example is simple.
+Once again, consider table
+.BR inventory ,
+which is as follows:
+.DM
+Item#   Onhand  Cost    Value   Description   
+-----   ------  ----    -----   --------------
+    1        3    50      150   rubber gloves 
+    2      100     X      500   test tubes    
+    3       -5    80     -400   clamps        
+    4       23    19      437   plates        
+    5      -99    24    -2376   cleaning cloth
+    6       89   147    13083   bunsen burners
+    7        5   175      875   scales        
+.DE
+.PP
+Several invalid values have crept into this table.
+You might wish to check that no item in column
+.B Onhand
+is less than zero.
+To do so, type the command:
+.DM
+validate 'Onhand < 0 {print "negative Onhand in line " NR}' < badinventory
+.DE
+.PP
+This prints the following on the standard output:
+.DM
+Item#   Onhand  Cost    Value   Description   
+-----   ------  ----    -----   --------------
+    1        3    50      150   rubber gloves 
+    2      100     X      500   test tubes    
+negative Onhand in line 3
+    3       -5    80     -400   clamps        
+    4       23    19      437   plates        
+negative Onhand in line 5
+    5      -99    24    -2376   cleaning cloth
+    6       89   147    13083   bunsen burners
+    7        5   175      875   scales        
+.DE
+.PP
+The variable
+.B NR
+means number of record or row.
+This variable is built into
+.BR awk ,
+which
+replaces it with the number of the line it is processing.
+.PP
+The next example is complex.
+Note that if you wish, you can write a command line for
+.B validate
+into a file, to create a customized validation command.
+You can put many tests and messages in one validation file.
+For example, the following command file, called
+.BR validateinv ,
+thoroughly checks table inventory:
+.DM
+echo validating badinventory
+.sp \n(pDu
+validate '{if (Onhand < 0 ) print "negative Onhand in line " NR; \e
+        if (Value < 0 ) print "negative Value in line " NR; \e
+        if (Cost ~ /[A-Za-z]/) print "letter in Cost in line " NR; }' \e
+        < badinventory
+.DE
+.PP
+To validate table
+.BR inventory ,
+just type:
+.DM
+	validating badinventory
+.DE
+.PP
+This prints the following on the standard output:
+.DM
+Item#   Onhand  Cost    Value   Description   
+-----   ------  ----    -----   --------------
+    1        3    50      150   rubber gloves 
+letter in Cost in line 2
+    2      100     X      500   test tubes    
+negative Onhand in line 3
+negative Value in line 3
+    3       -5    80     -400   clamps        
+    4       23    19      437   plates        
+negative Onhand in line 5
+negative Value in line 5
+    5      -99    24    -2376   cleaning cloth
+    6       89   147    13083   bunsen burners
+    7        5   175      875   scales        
+.DE
+.PP
+You may wish to redirect the output of
+.B validate
+to a file, bring it into your editor, and
+correct the errors and remove the error lines as you go.
+To make it easier to find those error lines in
+the editor, you could have all error lines contain a string
+that is easy to find, such as
+.BR ERROR .
+.PP
+If you only want to see the error lines, use the command
+.BR row .
+.SH "See Also"
+.SH "Logical Conditions"
+.B
+compute,
+row
+.R
+.br
+COHERENT Tutorials:
+.B
+Introduction to the awk Language
+.R