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<TITLE>NoSQL: Examples of perl expressions and statements</TITLE>
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<H2><A NAME="s11">11. Examples of perl expressions and statements</A> </H2>
<P>Following are some examples of PERL expressions and
statements of the type that might be used with NoSQL operators,
and their meaning. Note that the operator 'nsq-row' takes
a PERL expression while the operator 'nsq-compute' takes a
complete PERL statement.
<P>Expressions:
<P>
<BLOCKQUOTE><CODE>
<PRE>
COLA mat /XXX/
-- column COLA contains the pattern 'XXX'.
COLA nmat /XXX/
-- column COLA does NOT contain the pattern 'XXX'.
COLA mat /^XXX/
-- column COLA starts with the pattern 'XXX'.
COLA mat /XXX$/
-- column COLA ends with the pattern 'XXX'.
COLA ne null
-- column COLA is not null (but it could contain blanks).
COLA mat /^\s*$/
-- column COLA is null or contains only blank space.
COLA eq 'YYY'
-- column COLA equals the literal 'YYY'.
COLA mat /X..Y/
-- column COLA contains the pattern 'X..Y', which means
'X', followed by any two characters, then 'Y'.
COLA mat /X.*Y/
-- column COLA contains the pattern 'X.*Y', which means
'X', followed by any number of (including zero)
characters, then 'Y'.
NUMC eq 12
-- column NUMC equals 12.
COLA ne null && COLB ne null
-- column COLA and column COLB are not null (empty).
COLA eq 'ABC' || COLA eq 'BCD'
-- column COLA equals the literal 'ABC' or column COLB
equals the literal 'BCD'
</PRE>
</CODE></BLOCKQUOTE>
<P>Statements:
<P>
<BLOCKQUOTE><CODE>
<PRE>
COLA = COLB ;
-- set the value of column COLA to that of COLB.
NUMC = NUMC - 7 ;
-- decrement the value of column NUMC by 7.
NUMC -= 7 ;
-- (same as above).
NUMC = NUMC / 4 ;
-- divide the value of column NUMC by 4.
NUMC *= 2.3 ;
-- multiply the value of column NUMC by 2.3.
$abc++ ;
-- increment the value of variable $abc by 1.
++$abc ;
-- (same as above).
COLA = 'WORDS' ;
-- set the value of column COLA to the literal 'WORDS'.
NUMC = 12 ;
-- set the value of column NUMC to 12.
if( COLA mat /XXX/ ){ COLA .= 'YYY' ; }
-- If column COLA contains the pattern 'XXX' then add the
literal 'YYY' to the end.
COLA .= 'YYY' if COLA =~ /XXX/ ;
-- (same as above).
if( COLA eq 'ABC' || COLA eq 'BCD' ){ COLA = 'XXX' ; }
-- If column COLA equals 'ABC' or 'BCD' set the value of
COLA to 'XXX'.
</PRE>
</CODE></BLOCKQUOTE>
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