Rdb: Ruby-Nachbau der MWC /rdb-Werkzeuge

man/domain.man

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+.TH domain "" "" "/rdb Command"
+.PC "Display invalid values in a column"
+\fBdomain \fIdomaintable \fB[\fIstring ...\fB] [< \fIone-column-table\fB]\fR
+.PP
+.II "table^validate"
+.II "validate table"
+.II "domain table"
+The command
+.B domain
+displays all strings or all rows in
+.I one-column-table
+that do not match any entry in the
+.IR domaintable .
+.PP
+.B domain
+is useful for validating that each item in a column
+is legitimate.
+First, build a file that consists of a list of all legal values.
+In relational theory, these values are called the
+.I domain
+of the column.
+(You can also use the command
+.B validate
+to validate numbers and short lists of valid strings.)
+.PP
+To check the domain of a column in a multicolumn table, simply use the
+command
+.B column
+to project the column you want.
+.PP
+The
+.I domaintable
+must be sorted because it be searched by the command
+.B search
+using the binary fast-access method (\fB\-mb\fR).
+.B domain
+is a shell script, so you can edit it to change its search method,
+.SH Example
+You might have an order file for cars like this:
+.DM
+Qty     Model   Colors  Options
+------- ------- ------- -------
+1       sedan   black   3
+1       sedan   green   1
+1       sedan   farble  4
+3       sedan   red     5
+2       convert white   1
+1       sedan   purple  2
+1       sedan   yellow  4
+3       convert blue    2
+.DE
+.PP
+You would also need a sorted file of possible car colors:
+.DM
+Colors
+------
+black
+blue
+carmel
+green
+purple
+red
+silver
+white
+.DE
+.PP
+Now we can validate the
+.B Color
+column and see all unacceptable colors:
+.DM
+	column Colors < orders | domain colors
+.DE
+.PP
+This produces the following output:
+.DM
+Colors
+------
+farble
+yellow
+.DE
+.PP
+.B domain
+complains about
+.B farble
+and
+.B yellow
+because neither color is in our domain list.
+.PP
+You can invoke
+.B orders
+in the text editor and edit it,
+or add those colors to the approved list.
+In
+.B vi
+use the
+.B /pattern
+command to find all of the
+.I patterns
+in the orders file.
+Another approach is to type something like this:
+.DM
+	:g/farble/s//purple/g
+.DE
+.PP
+This
+.B vi
+command will find all instances of
+.B farble
+and change them to
+.BR purple .
+.PP
+You can also validate strings written on the command line.
+For example, the command
+.DM
+	domain colors red blue purple farble yellow green
+.DE
+.PP
+also prints the output:
+.DM
+farble
+yellow
+.DE
+.PP
+These command-line stings should be quoted if they have
+any special characters in them.
+They are sought by the command
+.BR grep .
+If they contain a dollar sign `$',
+it should be protected with three backslashes:
+this expression is scanned both by the shell and by
+.BR grep ,
+and it takes three backslashes to get one
+backslash through to
+.BR grep .
+.SH "See Also"
+.B
+column,
+search,
+validate,
+ve
+.R
+.br
+COHERENT Lexicon:
+.B
+egrep,
+grep,
+sort,
+uniq
+.R
+.SO domain