Rdb: Ruby-Nachbau der MWC /rdb-Werkzeuge

man/row.man

@@ -0,0 +1,189 @@
+.TH row "" "" "/rdb Command"
+.PC "Make a new table where rows match logical condition"
+\fBrow '\fIcolumn condition column-or-value ..\fB' < \fItable\fR
+.PP
+.II "table^split"
+.II "table^create new"
+.II "row^select via expression"
+The command
+.B row
+creates a new table from
+.IR table .
+The new table
+consists of only those rows that meet
+.IR condition .
+.PP
+.B row
+uses a script written in the
+.B awk
+language, which gives you great power for specifying the logical condition.
+.PP
+Several conditional expressions can be combined with the
+logical AND (&&) and OR (||) operators.
+Because the logical conditions are represented by special characters,
+they must be enclosed by apostrophes, to protect them from being
+interpreted by the shell.
+If you have special characters within a column name,
+enclose the column name in quotation marks.
+.SH Example
+First a simple example.
+Consider table
+.B inventory :
+.DM
+Item    Onhand  Cost    Value   Description
+----    ------  ----    -----   -----------
+1       3       5       15      rubber gloves
+2       100     1       100     test tubes
+3       5       8       40      clamps
+4       23      2       51      plates
+5       99      2       97      cleaning cloth 
+6       89      18      1602    bunsen burners 
+7       5       175     875     scales
+.DE
+.PP
+To make a table of all of the parts that cost more that $5, type:
+.DM
+	row 'Cost > 5' < inventory
+.DE
+.PP
+The new table appears as follows:
+.DM
+Item    Onhand  Cost    Value   Description
+----    ------  ----    -----   -----------
+3       5       8       40      clamps
+6       89      18      1602    bunsen burners
+7       5       175     875     scales
+.DE
+.PP
+Now a more complex example.
+If you want a table of all the burners
+and of all of the items of which we have fewer than ten in stock, type:
+.DM
+	row 'Description ~ /burner/ || Onhand < 10' < inventory
+.DE
+.PP
+The new table appears as follows:
+.DM
+Item    Onhand  Cost    Value   Description
+----    ------  ----    -----   -----------
+1       3       5       15      rubber gloves
+3       5       8       40      clamps
+6       89      18      1602    bunsen burners
+7       5       175     875     scales
+.DE
+.PP
+The string
+.B "~ /burner/"
+searches for the string ``burner'' anywhere in the column.
+The double pipe (||) means logical OR.
+.SH "Column Names"
+The commands
+.BR row ,
+.BR compute ,
+and
+.B validate
+recognize column names as upper- and lower-case letters,
+digits, and the underscore `_'.
+The regular expression is [A-Za-z0-9_].
+If you have any other characters in your column names, put
+apostrophes or quotation marks around them.
+.PP
+.B row
+compares the recognized strings with the table's head line.
+Only if it finds a match does it convert the string
+to the \fB$1, $2...\fR column positions that
+.B awk
+needs.
+.SH "awk's Reserved Words"
+.B awk
+is the pattern-scanning language that does all of the work for the
+commands
+.BR row ,
+.BR compute ,
+and
+.BR validate .
+.PP
+.B awk
+recognizes the following words as having special significance.
+If you name a columns with any of these reserved words
+and then try to use them in a query, the
+.B /rdb
+commands that are built around
+.B awk
+turn them into column positions and
+.B awk
+does not see them.
+It is best to avoid these names as column heads or simply
+capitalize the first letter of each of your column names.
+.PP
+This list also indicates the many functions you have with
+.BR awk .
+However, do not rely on the following descriptions.
+The tutorial section of
+your COHERENT manual contains a summary of the
+.B awk
+language.
+.PP
+Please note that this list of
+.B awk
+functions and reserved words comes from UNIX System V.
+Other implementations of
+.B awk
+may not contain all of these functions.
+.DM
+.ta 1.5i
+\fIReserved Word	Description\fR
+.tc .
+\fBBEGIN\fR	Pattern that matches before first input record
+\fBEND\fR	Pattern that matches after last input record
+\fBbreak\fR	Exit the nearest \fBfor\fR or \fBwhile\fR loop
+\fBcontinue\fR	Go to next iteration of \fBfor\fR or \fBwhile\fR loop
+\fBelse\fR	Used in \fBif then else\fR expression
+\fBexit\fR	Leave program entirely, as if at end of input
+\fBexp\fR	Raise number to a power
+\fBfor\fR	\fBfor (\fIexpression\fB ; \fIcondition\fB; \fIexpression\fB)\fR
+\fBgetline\fR	Get next input line
+\fBif\fR	\fBif (\fIcondition\fB) \fIstatement \fB[else \fIstatement\fB]\fR
+\fBin\fR	\fBfor (\fIvariable \fBin \fIarray\fB) \fIstatement\fR
+\fBindex\fR	\fBindex ( \fIstring1\fB, \fIstring2 \fB)\fR
+\fBint\fR	Truncate argument to integer
+\fBlength\fR	Return current line length, or length of argument
+\fBlog\fR	Return log (to base 2) of argument
+\fBnext\fR	Skip to next record and reexecute all commands
+\fBprint\fR	Output variables
+\fBprintf\fR	\fBprintf ("\fIformat\fB", \fIvariable\fB, ... )\fR
+\fBsplit\fR	\fBsplit (\fIstring\fB, \fIarrayname\fB, \fIseparator\fB)\fR
+\fBsprintf\fR	\fBsprintf ("\fIformat\fB", \fIvariable, ... \fB)\fR
+\fBsqrt\fR	Return square root of argument
+\fBsubstr\fR	\fBsubstr ( \fIstring\fB, \fIstart\fB, \fInumber \fB)\fR
+\fBwhile\fR	\fBwhile ( \fIcondition\fB ) \fIstatement\fR
+.tc
+.DE
+.PP
+Although
+.B row
+is built around the
+.B awk
+language,
+.B row
+has the advantage of knowing about the names of the columns.
+Therefore, you can use column names instead
+of column positional numbers.
+To grasp the full power of
+.B row
+and
+.BR compute ,
+read the COHERENT manual's tutorial on
+.BR awk .
+.SH "See Also"
+.B
+compute,
+row,
+select,
+validate
+.R
+.br
+COHERENT Tutorials:
+.B
+Introduction to the awk Language
+.R