lower_upper

lower_upper{l:str, u:str}

A relation generator. Can convert string l into upper case (u) and vice-versa.

Examples

lower to upper

lower_upper(l:="hello world")

u

HELLO WORLD

u
HELLO WORLD

upper to lower

lower_upper(u:="HELLO WORLD")

l

hello world

l
hello world

bulk operation

$S{*, l:=SNAME} & lower_upper

SNO l STATUS CITY u

S1 Smith 20 London SMITH
S2 Jones 10 Paris JONES
S3 Blake 30 Paris BLAKE
S4 Clark 20 London CLARK
S5 Adams 30 Athens ADAMS

SNO	l	STATUS	CITY	u
S1	Smith	20	London	SMITH
S2	Jones	10	Paris	JONES
S3	Blake	30	Paris	BLAKE
S4	Clark	20	London	CLARK
S5	Adams	30	Athens	ADAMS

Joining with a relation with either l or u causes the operation to apply to every tuple.

bulk operation - composed

$S{*, l:=SNAME}(lower_upper){*, SNAME:=u}

SNO STATUS CITY SNAME

S1 20 London SMITH
S2 10 Paris JONES
S3 30 Paris BLAKE
S4 20 London CLARK
S5 30 Athens ADAMS

SNO	STATUS	CITY	SNAME
S1	20	London	SMITH
S2	10	Paris	JONES
S3	30	Paris	BLAKE
S4	20	London	CLARK
S5	30	Athens	ADAMS

Note: this first renames SNAME to l to match the lower_upper{l}, then it composes that with lower_upper (which removes the common l attribute) and then it finally renames the added u back to SNAME, effectively replacing the original SNAME with an uppercased version.