I am totally new to FoxPro (and quite fluent with MySQL).
I am trying to execute this query in FoxPro:
update expertcorr_memoinv.dbf set 'Memo' = (select 'Memo' from expertcorr_memoinv.dbf WHERE Keymemo='10045223') WHERE Keydoc like "UBOA"
I got the error:
function name is missing )
How can I fix it?
In FoxPro SQL statements you would not 'single-quote' column names. In Visual FoxPro version 9 the following sequence would run without errors:
CREATE TABLE expertcorr_memoinv (keydoc Char(20), keymemo M, Memo M)
Update expertcorr_memoinv.dbf set Memo = (select Memo from expertcorr_memoinv.dbf WHERE Keymemo='10045223') WHERE Keydoc like "UBOA"
If you would provide a few sample data and an expected result, we could see whether the line you posted would do what you want after correcting the single-quoted 'Memo' names.
NB 1: "Memo" is a reserved word in FoxPro.
NB 2: As you know, the ";" semicolon is a line-continuation in Visual FoxPro, so that a longer SQL statement can be full; of; those;
So that the Update one-liner could be written as:
Update expertcorr_memoinv ;
Set Memo = (Select Memo From expertcorr_memoinv ;
WHERE Keymemo='10045223') ;
WHERE Keydoc Like "UBOA"
NB 3: Alternatively, you can SQL Update .... From... in Visual FoxPro, similar to the Microsoft SQL Server feature. See How do I UPDATE from a SELECT in SQL Server?
I would do that just as Stefan showed.
In VFP, you also have a chance to use non-SQL statements which make it easier to express yourself. From your code it feels like KeyMemo is a unique field:
* Get the Memo value into an array
* where KeyMemo = '10045223'
* or use that as a variable also
local lcKey
lcKey = '10045223'
Select Memo From expertcorr_memoinv ;
WHERE Keymemo=m.lcKey ;
into array laMemo
* Update with that value
Update expertcorr_memoinv ;
Set Memo = laMemo[1] ;
WHERE Keydoc Like "UBOA"
This is only for divide & conquer strategy that one may find easier to follow. Other than that writing it with a single SQL is just fine.
PS: In VFP you don't use backticks at all.
Single quotes, double quotes and opening closing square brackets are not used as identifiers but all those three are used for string literals.
'This is a string literal'
"This is a string literal"
[This is a string literal]
"My name is John O'hara"
'We need 3.5" disk'
[Put 3.5" disk into John's computer]
There are subtle differences between them, which I think is an advanced topic and that you may never need to know.
Also [] is used for array indexer.
Any one of them could also be used for things like table name, alias name, file name ... (name expression) - still they are string literals, parentheses make it a name expression. ie:
select * from ('MyTable') ...
copy to ("c:\my folder\my file.txt") type delimited
Related
I have the following:
string text = "Select [id] AS [FROMId] FROM [TASK] ORDER BY id"
and I want to use text.IndexOf("FROM") in order to find where the FROM starts.
I want to find the position of FROM and not the position of FROMId.
LastIndexOf or FirstIndexOf are not correct answers cause the text could be anything like
string text = #"Select [id] AS [FROMId],
newId as [newFROMId] FROM [TASK] ORDER BY [FROMId]"
I need the indexof to do exact matching.
Any ideas?
Since FROM is an SQL reserved word that will generally have spaces on either side, you could look for that then, since that will give you the address of the space before the F, add one to get the location of the F itself:
int index = text.IndexOf(" FROM ") + 1
This may not necessarily take care of all edge cases(a) but, to do that properly, you may have to implement an SQL parser to ensure you can correctly locate the real from keyword and distinguish it from other possibilities.
(a) Such as things like:
select [a]FROM[tble] ...
select 'got data from unit #' | unit from tbl ...
and so on.
Excuse me, occasionally I refer with some problem that maybe it's already been fixed. In any case, I would appreciate a clarification on vs.
I have a TariffeEstere table with the fields country, Min, Max, tariff
from which to extract the rate for the country concerned, depending on whether the value is between a minimum and a maximum and I should return a single record from which to extract its tariff:
The query is:
stsql = "Select * from QPagEstContanti Where country = ' Spain '
and min <= ImpAss and max >= ImpAss"
Where ImpAss is a variable of type double.
When I do
rstariffa.open ststql,.....
the recodset contains a record if e.g. ImpAss = 160 (i.e. an integer without decimals), and then the query works, but if it contains 21,77 ImpAss (Italian format) does not work anymore and gives me a syntax error.
To verify the contents of the query string (stsql) in fact I find:
Select * from QPagEstContanti Where country = 'Spain' and min < = 21,77 and max > = 21,77
in practice the bothering and would like a comma decimal, but do not know how do.
I tried to pass even a
format (ImpAss, "####0.00"),
but the value you found in a stsql is 21,77 always.
How can I fix the problem??
It sounds like the underlying language setting in SQL is expecting '.' decimals instead of ',' decimal notation.
To check this out - run the DBCC useroptions command and see what the 'language' value is set to. If the language is set to English or another '.' decimal notation - it explains why your SQL string is failing with values of double.
If that's the problem, the simplest way to fix it is to insert the following line after your stsql = statement:
stsql = REPLACE(stsql, ",", ".")
Another way to fix it would be to change the DEFAULT_LANGUAGE for the login using the ALTER LOGIN command (but this changes the setting permanently)
Another way to fix it would be to add this command to the beginning of your stsql, which should change the language for the duration of the rs.Open:
"SET LANGUAGE Italian;"
I have:
BEFORE Gsub sql ::::
SELECT record_type.* FROM record_type WHERE (name = 'Registrars')
sql = sql.gsub(/SELECT\s+[^\(][A-Z]+\./mi,"SELECT ")
AFTER GSUB SQL ::::
SELECT record_type.* FROM record_type WHERE (name = 'Registrars')
The desired result is to remove the "record_type." from the statement:
So it should be :
SELECT * FROM record_type WHERE (name = 'Registrars')
After the regex is run.
I didn't write this, it's in the asf-soap-adaptor gem. Can someone tell me why it doesn't work, and how to fix?
I suppose it should be written like this...
sql = sql.gsub(/SELECT\s+[^\(][A-Z_]+\./mi,"SELECT ")
... as the code in the question won't match if the field name contains _ (underscore) symbol. I suppose that's why this code is in gem: it can work in some conditions (i.e., with underscoreless field names).
Still, I admit I don't understand why exactly this replacement should be done - and shouldn't it include 0-9 check as well (as, for example, 'record_id1' field still won't be matched - and replaced - by the character class in the regular expression; you may have to either expand it, like [0-9A-Z_], or just replace completely with \w).
so your before and after gsubs are the same? I can't tell you why it doesn't work if you dont tell me your expected result. Also for help with interpreting ruby regular expressions check out rubular.com
I would like to know whats the XPath equivalent to SQL In query. Basically in sql i can do this:
select * from tbl1 where Id in (1,2,3,4)
so i want something similar in XPath/Xsl:
i.e.
//*[#id= IN('51417','1121','111')]
Please advice
(In XPath 2,) the = operator always works like in.
I.e. you can use
//*[#id = ('51417','1121','111')]
A solution is to write out the options as separate conditions:
//*[(#id = '51417') or (#id = '1121') or (#id = '111')]
Another, slightly less verbose solution that looks a bit like a hack, though, would be to use the contains function:
//*[contains('-51417-1121-111-', concat('-', #id, '-'))]
Literally, this means you're checking whether the value of the id attribute (preceeded and succeeded by a delimiter character) is a substring of -51417-1121-111-. Note that I am using a hyphen (-) as a delimiter of the allowable values; you can replace that with any character that will not appear in the id attribute.
I would like to store a mySQL query in a file. I plan on having to string replace parts of it with variables from my program.
I played around with the 'eval' method in ruby, and it works, but it feels a little clumsy.
Using irb I did the following.
>> val = 7
=> 7
>> myQuery = "select * from t where t.val = \#{val}" #escaped hash simulates reading it from file
=> "select * from t where t.val = \#{val}"
>> myQuery = eval "\"#{myQuery}\""
=> "select * from t where t.val = 7"
As you can see it works! But to make it work I had to wrap the 'myQuery' variable in escaped quotes, and the whole thing looks a little messy.
Is there an easier way?
Generally, you should not use string interpolation to build SQL queries. Doing so will leave you open to SQL injection attacks, in which someone supplies input that has a closing quote character, followed by another query. For instance, using your example:
>> val = '7; DROP TABLE users;'
=> "7; DROP TABLE users;"
>> myQuery = "select * from t where t.val = \#{val}"
=> "select * from t where t.val = \#{val}"
>> eval "\"#{myQuery}\""
=> "select * from t where t.val = 7; DROP TABLE users;"
Even without malicious input, you could simply accidentally execute code that you weren't intending to, if for instance someone included quote marks in their input.
It is also generally a good idea to avoid using eval unless absolutely necessary; it makes it possible that if you have a bug in your program, someone could execute arbitrary code by getting it passed to eval, and it makes code less maintainable since some of your source code will be loaded from places other than your regular source tree.
So, how do you do this instead? Database APIs generally include a prepare command, which can prepare to execute an SQL statement. Within that statement, you can include ? characters, which represent parameters that can be substituted within that statement. You can then call execute on the statement, passing in values for those parameters, and they will be executed safely, with no way for someone to get an arbitrary piece of SQL executed.
Here's how it would work in your example. This is assuming you are using this MySQL/Ruby module; if you are using a different one, it will probably have a similar interface, though it may not be exactly the same.
>> val = 7
>> db = Mysql.new(hostname, username, password, databasename)
>> query = db.prepare("select * from t where t.val = ?")
>> query.execute(val)
You can use ERB templates instead - read them from the files and interpolate the variables (convert <%= something %> tags into the actual values).
Here's the official doc, it's quite complete and straightforward.
You can use printf like syntax for string replacement
"123 %s 456" % 23 # => "123 23 456"
This only works if your program knows in advance which variables to use.
Could you use parametrized queries?
I don't know off hand how to do so in ruby, but basically it involves marking your SQL statement with commands that SQL recognizes are replaces with parameters that are sent in addition to your statement.
This link might help: http://sqlite-ruby.rubyforge.org/sqlite3/faq.html#538670816