I am writing a query, where I am using the division operator. For some reason I can't get it to work properly, and I can't see why.
pol = pi allergen (sigma allergy_type = 'pollen' (allergies))
tmp = (patient_allergies/pol)
tmp
The above is my query. In pol I am retrieving all allergens, who has the allergy type pollen. This gives me a 1 column, two rows table, which content is the two allergens who has allergy_type pollen.
tmp:
Patient_allergies is a 2 column, 23 row table. The first column is allergens, second column is ssn for the people with those allergens.
What I am trying to do, is to get everyone in patient_allergies, who has the two allergens I found in pol. I'm pretty sure I need to division operator for this, but it returns an empty list, which is incorrect for what I am trying to do.
EDIT: I am using this relational algebra calc, provided by our university: dbis-uibk.github.io/relax/calc/local/uibk/local/0 There is a division operator with another symbol, but yields the same result
Related
I have to be honest that I don't quite understand Lua that well yet. I am trying to overwrite a local numeric value assigned to a set table address (is this the right term?).
The addresses are of the type:
project.models.stor1.inputs.T_in.default, project.models.stor2.inputs.T_in.default and so on with the stor number increasing.
I would like to do this in a for loop but cannot find the right expression to make the entire string be accepted by Lua as a table address (again, I hope this is the right term).
So far, I tried the following to concatenate the strings but without success in calling and then overwriting the value:
for k = 1,10,1 do
project.models.["stor"..k].inputs.T_in.default = 25
end
for k = 1,10,1 do
"project.models.stor"..j..".T_in.default" = 25
end
EDIT:
I think I found the solution as per https://www.lua.org/pil/2.5.html:
A common mistake for beginners is to confuse a.x with a[x]. The first form represents a["x"], that is, a table indexed by the string "x". The second form is a table indexed by the value of the variable x. See the difference:
for k = 1,10,1 do
project["models"]["stor"..k]["inputs"]["T_in"]["default"] = 25
end
You were almost close.
Lua supports this representation by providing a.name as syntactic sugar for a["name"].
Read more: https://www.lua.org/pil/2.5.html
You can use only one syntax in time.
Either tbl.key or tbl["key"].
The limitation of . is that you can only use constant strings in it (which are also valid variable names).
In square brackets [] you can evaluate runtime expressions.
Correct way to do it:
project.models["stor"..k].inputs.T_in.default = 25
The . in models.["stor"..k] is unnecessary and causes an error. The correct syntax is just models["stor"..k].
I need someone could help me out on how to trace the error of "mismatched data type" in visual foxpro 6.0 When I issues a command like this "insert into tmpcur from memvar".
tmpcur is a cursor having bulk numbers of columns and it is ready hard to trace which one is having mismatch in data type for insertion problem.
It is pretty difficult to trace the insertion loop of each record into VFP tables one by one unliked MSSQL profiler.
Appreciate to someone could help. Thanks.
This should help you. I have a temp cursor created with some bogus field / column names testing for types of character, integer, double, currency, date and time. Trying to follow what is the result of your scenario, I am taking the memory variable of "bbbb" which should be double (or numeric at the least), and changed it to a string.
I am then HOLDING the error trapping routine that MAY be in effect, then setting my own (as I don't think try/catch existed in VFP6.. it may, but I just don't remember. So, I did an ON ERROR, set a variable to true. Then, I default it to false, try the insert, then check the flag. If the flag IS set, then I go into a loop and try for each column in the given table/alias (in my example it is "C_Tmp", so replace with your table/alias). It goes through each variable, and if the data type is different from the table structure, it will dump the column name and table / memory value for you to review.
You could put this to a log file or something.
Now, another consideration. Some types are completely valid and common for implied conversion, such as character and memo fields can both get strings. Integer, double, float, currency can all work with generic "numeric" values.
So, if you encounter these differences, then we can go one level further and look for comparable types, but let me know and we can adjust as needed.
At least this should give you a huge jump to your insert issue.
CREATE CURSOR C_tmp ( cccc c(10), iiii i, bbbb b(2), ccyyyy y, ddd d, tttt t )
SCATTER MEMVAR memo
m.bbbb = "wrong data type, was double with 2 decimal"
lcHoldError = ON("ERROR")
ON ERROR lFailInsert = .t.
lFailInsert = .f.
INSERT INTO C_Tmp FROM memvar
IF lFailInsert
FOR lnI = 1 TO FCOUNT( "C_Tmp" )
lcTmp = FIELD( lnI, "C_Tmp" )
IF NOT TYPE( "C_Tmp." + lcTmp ) == TYPE( "m.&lcTmp" )
? "Invalid " + lcTmp + ", C_Tmp.&lcTmp, m.&lcTmp
ENDIF
ENDFOR
ENDIF
ON ERROR &lcHoldError
Using Oracle 11gR2 Expression Edition.
My data looks like following
ordertype
---------
ZOCO
ZOSA
ZOST
We are trying to find out records where the column is not between a certain range of values.
If I run a query with <= and >= operators:
SELECT * FROM table where ordertype <= 'ZAAA' OR ordertype >= 'ZZZZ';
then I get 0 results. This is the right answer.
However, if I use NOT BETWEEN:
SELECT * FROM table where ordertype NOT BETWEEN 'ZAAA' AND 'ZZZZ';
, then it gives multiple hits.
My understanding is that both syntax should give the same result but they are not. What am I missing? Reason I want to use NOT BETWEEN because a lot of our existing code already has this syntax and I do not want to change it without understanding the reasons.
Thank you.
Thanks for all those who posted. I ran the queries again and after fixing the "OR" in the first query, the results are the same. I still have the question of why Oracle character sorting is not recognizing it as expected, but my question which is about difference between NOT BETWEEN and <> was a false alarm. I apologize for confusion.
SELECT * FROM table where ordertype <= 'ZAAA' AND ordertype >= 'ZZZZ';
No string can be <= 'ZAAA' and >= 'ZZZZ'.
You need to use a disjunction instead:
SELECT * FROM table where ordertype < 'ZAAA' OR ordertype > 'ZZZZ';
BTW, given that BETWEEN is inclusive, NOT BETWEEN is exclusive
This is a common pitfall. you have to remember the De Morgan's Laws:
not (A and B) is the same as (not A) or (not B)
Feel free to experiment with this simple live example to convince yourself that those results are quite coherent: http://sqlfiddle.com/#!4/d41d8/38326
That being said, the only way (I can see) for the string like ZOCO for not being between ZAAA and ZZZZ would be:
having some hidden character just behind the Z (i.e.: 'Z'||CHR(0)||'OCO')
or using a locale such as Z-something is actually considered as a different letter, with a collation order outside of the given range. I don't know if such locale exists, but for example, in Welch, LL is considered as a single letter that should be sorted after the plain L. See http://en.wikipedia.org/wiki/Alphabetical_order#Language-specific_conventions
or having homogplyphs such as 0, 𐒠 or О instead of O in your data.
If it's not between the values, it has to be either < OR >, not AND.
In the first query, you ask for the records that are at the same time less than 'ZAAA' and also greater than 'ZZZZ'. Of course, there is no such value that fullfills both requirements, hence zero records are returned.
In the second query, you ask for records, that are either less than 'ZAAA' or greater than 'ZZZZ' (ie not between those boundaries [not between...]). There is a possibility that such records exist, and as your select statement proves, there are indeed such records, that are returned by the statement.
Your understanding that both statements are same is incorrect. NOT BETWEEN is not evaluated the way you're thinking. It simply returns the results which fall outside evaluation of BETWEEN for the parameters.
IF you check Oracle documentation for BETWEEN, it says -
The value of
expr1 NOT BETWEEN expr2 AND expr3
is the value of the expression
NOT (expr1 BETWEEN expr2 AND expr3)
Is there any way that
PadRight[a \[PlusMinus] b,2,""]
Returns
{a \[PlusMinus] b,""}
Instead of
a \[PlusMinus] b \[PlusMinus] ""
?
I believe that i need to somehow deactivate the operator properties of [PlusMinus].
Why do i need this?
I'm creating a program to display tables with physical quantities. To me, that means tables with entries like
(value of a) [PlusMinus] (uncertainty of a)
When i have several columns with different heights, i'm stuffing the shorter ones with "", so i can use Transpose the numeric part of the table.
If the column has more than one entrie, there's no problem:
PadRight[{a \[PlusMinus] b,c \[PlusMinus] d},4,""]
gives what i want:
{a \[PlusMinus] b,c \[PlusMinus] d,"",""}
It is when the column has only one entrie that my problem appears.
This is the code that constructs the body stuffed with "":
If[tested[Sbody],1,
body = PadRight[body, {Length[a], Max[Map[Length, body]]
With
tested[a__] :=
If[Length[DeleteDuplicates[Map[Dimensions, {a}]]] != 1, False,
True];
, a function that discovers if is arguments have the same dimension
and
a={Quantity1,Quantity2,...}
Where the quantities are the one's that i want on my table.
Thanks
First you need to be aware of that any expression in Mathematica is in the form of Head[Body]
where body may be empty, a single expression or a sequence of expressions separated by commas
Length operate on expressions, not necessarily lists
so
Length[PlusMinus[a,b]]
returns 2 since the body of the expression contains to expressions (atoms in this case) that are a and b
Read the documentation on PadRight. The second argument define the final length of the expression
so
PadRight[{a,b},4,c] results with a list of length 4 with the last two elements equal to
PadRight[{a,b},2,c] results with the original list since it is already of length 2
Therefore
PadRight[PlusMinus[a,b],2,anything] just returns the same PlusMinus[a,b] unchanged since it is already of length 2
so, youר first example is wrong. You are not able to get a result with head List using PadRight when you try to pad to an expression with head PlusMinus
There is no problem of executing
PadRight[PlusMinus[a,b],3,""]
but the result looks funny (at best) and logically meaningless, but if this is what you wanted in the first place you get it, and following my explanations above you can figure out why
HTH
best
yehuda
I'm using basic .net DataColumns and the associated Expression property.
I have an application which lets users define which columns to select from a database table. They can also add other columns which perform expressions on the data columns resulting in a custom grid of information.
The problem I have is when they have a calculation column along the lines of "(C2/C3)*100" where C2 and C3 are data columns and the value for C3 is zero. The old "divide by zero" issue.
The simple answer would be to convert the expression to "IIF(C3 = 0, 0, (C2/C3)*100)", however we don't expect the user to know to do that and at compile time I don't know what columns are defined. So I would have to programmatically determine which columns are being used in a division in order to construct the IIF clause. That could get quite tricky.
Is there another way to not throw an error and replace the result with 0 if a "Divide By Zero" error occurs?
Ok, I found a way. The key is to use Double and not Decimal for the column type, e.g. in the example above C3 should be a Double. This will result in a result of Infinity instead, which can be evaluated against using the expression as a whole.
E.g.
IIF(CONVERT(([C4] / [C3] )*100, 'System.String') = 'NaN' OR CONVERT(([C4] / [C3] )*100, 'System.String') = 'Infinity' OR CONVERT(([C4] / [C3] )*100, 'System.String') = '-Infinity', 0, ([C4] / [C3] )*100)
Decimal it seems doesn't provide that Infinity option.