- :
useW2
opy to field ,
3 | |
. , , , dBASE, . 4 = W2[, ]
. , , .
. (, ,...) (,0,...). [0] , [0] , .
, , . . :
1. _ < > ,
=,#,>,=>,<,<=. , > 100.
2. __1 < > _ _2. , > .
.
T=R[p],
R - ;
- ;
- .
5 = W 1 [ = ""]
dBASE copy for,
, use W1 copy to X6 for =>
copy , .
, . dBASE .
R1 R2, .
= U(R1, R2) , R1, R2.
= I(R1, R2) , R1 R2 .
= M(R1, R2) R 1, R2.
4 W3,
7 | |
7 = U (4, W3).
W3 | |
dBASE append,
|
|
useX4
append from W3,
4 W3. .
. , , . :
__1 < > __2,
__1 , __2 - . :
T=Rl[p]R2,
R1 R2 - ,
- , - .
:
"=",
__1 __2 , , ,
.
= R1 * R2.
W1 ,
8 | |||||
1200 2000 | 1400 200 170 100 |
W1 7 = , . 7 W1 ( ). W1 7 . . , 8 .
DBASE :
SELECT 1
USE W1 && W1
SELECT 2
USE 7 && 7
SELECT 1
JOIN WITH 7 TO X9 FOR =7-> FIELDS , , 7->, ,
with , for , fields . .
, :
X10=W1*W2
, .10
1.6.110 | |||||
1 | |||||
23 | |||||
23 | |||||
23 | |||||
23 | |||||
2 | |||||
|
|
, , , , . . 2.2 , .
, . R S , R * S I(R,S).
R S , , , R * S R S.
, .
,
1.6.1.1 X1=R*S X2=S*R
, , .
,
Y1=(R*S)*T Y2=R*(S*T)
. , , XI 2 (Y1 Y2 ). , Y1 Y2 ( ), Y1 Y2 .
. Y(, ), , .
, .
X11 = Y[ = "" AND = ""]
( AND "") , , X11 .
, " ". (,) , b ( ) .
imB(a)={bl,b2,...,bk},
im - "",
- , , - , b1, b2,...,bk - .
"" "" .
im ("") = {"","po, }
im () = {"","",""}
im ("")Ç("")= {"","")
( , , , 2, ) ,
- .
, - W(A,B) ( Y) - V(A). - ;
Q(B), - V(A), - W(A,B).
Q = D (W,V).
D - .
XI 2 = D (Y,Z) :
|
|
XI 2 |
DBASE ,
. , .