% @(#)createcrul.hlq	17.1.1.1 (ESO-IPG) 01/25/02 17:50:00
%++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
%.COPYRIGHT  (c)  1993 European Southern Observatory
%.IDENT      createrule.hlq
%.AUTHOR     05-MAY-93, IPG/ESO
%.KEYWORDS   MIDAS, help files, 
%.PURPOSE    On-line help file for the command: CREATE/RULE
%.VERSION    1.0  MP : Creation, 05-MAY-93
%----------------------------------------------------------------
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SECTION./RULE
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CREATE/CRULE					   MP  05-MAY-93
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CREATE/CRULE  table rule
	 create an classification rule for a given Observation Summary Table
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Purpose:    
	 create an classification rule for a given Observation Summary Table
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Syntax:     
            CREATE/CRULE  table descr
 \\
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            table  = input Observation Summary Table 
 \\
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            descr  = descriptor of input table that will contain the 
                     created rule.
 \\
\ap\sa
See also: 
            CREATE/OST, EDIT/TABLE, CLASSIFY/IMAGE, SELECT/TABLE
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Note:       
            1) The command creates and edits using EDIT/TABLE a temporary table
               containing two columns. The first one, labelled ":COLUMN" 
               contains the labels of the columns of the input table. 
               In the second one, labelled ":RULE" ,constraints to be applied
               to the values of these columns should be entered. Relational 
               operators may be used (e.g., >, <, <=, != or =, default is =)
               as well as logical operators (\&, |)
               Values or range of values have to be specified. ("*" is the
               wildcard character, "~" ignores case and the ".." specifies 
               a range of values).
               Constraints applied to more than one column will be ANDed. 
               
              
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            2) These constraints will be converted into selection  criteria
               suitable for the SELECT/TAB command and will be stored in 
               the character descriptor descr (maximum length 256) of the table.\\
               The descriptor will be overwritten if it already exists.
               Furthermore, the command cannot store the selection criteria 
               into the standard descriptors of the table
               (TBLENGTH, TBLOFFST, TBLCONTR, TSELTABL, TLABLxxx)
 \\
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Examples:
\ex
            CREATE/CRULE  ntt  DARK
            creates a rule for flagging BIAS  exposures and stores the
            derived selection criteria into the descriptor BIAS of the table ntt. \\
            The command  will enter the table editor  and the constraints on
            the values of the columns of the OST may be entered as follows: 
\\{\tt    
            COLUMN          |RULE                    |     
\\
            ----------------------------------------- 
\\
            MJD             |                        |
\\
            IDENT           | =~*BIAS*|*DARK*        |
\\
            RA              |                        |
\\
            DEC             |                        |
\\
            EXPTIME         | =0                     |
\\
            -----------------------------------------   
\\}         
            These constraints will be translated into the following selection 
            criteria:\\
            :IDENT.EQ."*~BIAS*.OR.:IDENT.EQ."*~DARK*".AND.:EXPTIME.EQ.0
            which is the format required by command SELECT/TABLE
\xe \sxe