I want SQLAlchemy to generate the following SQL code:
SELECT t171 AS "3Harm" FROM production
I've been playing around with something similar to this SQLAlchemy ORM snippet:
session.query(Production.t171.label('3harm'))
The problem here is that this doesn't properly quote "3harm" in the generated SQL. Instead of "3harm" this generates the unquoted 3harm, which is invalid because it starts with a numerical character and therefore raises the following Oracle exception:
ORA-00923: FROM keyword not found where expected
I can get this to work by capitalizing any character in the alias name:
session.query(Production.t171.label('3Harm'))
But I would still prefer to use all lowercase column names since the rest of my program is standardized for all lowercase. Any idea how to force quote the lowercase version?
Found the solution while looking for something else.
Any column can be forced to use quotes with column.quote = True.
So for the original example:
column = Production.t171.label('3harm')
column.quote = True
session.query(column)
Success!
The SQL you want to generate isn't valid; rather than this:
SELECT t171 AS '3Harm' FROM production
... you need the identifier to be enclosed in double quotes, not single quotes:
SELECT t171 AS "3Harm" FROM production
So it looks like you should be able to do this:
session.query(Production.t171.label('"3harm"'))
or maybe:
session.query(Production.t171.label("3harm"))
But I don't use SQLAlchemy and I don't have any way to check if either is valid; you might need to escape the double quotes in the first one, for instance, though from this perhaps the second is more likely to work... and I don't understand why 3Harm would work unquoted.
Related
I'm just curious about switch/case in UiPath.
Everywhere else in UiPath, strings must have double quotes or stored in variables, however in switch/case, it seems different.
Every "case" is interpreted as string, regardles of the quotes.
How to use variables in there when they're interpreted as string?
You cant use variable in switch case in UiPath. However you can use following expression in Expression property helps switch dynamically.
Array.IndexOf({var1,var2,var3},item.ToString)
Something like below screenshot
Hope this helps
I have a script I'm trying to run via sqlplus. At the top of the script, I have "SET DEFINE OFF" set. However, when I run it, I'm receiving this error:
SP2-0552: Bind variable "CHANDAWALA" not declared.
I believe this is happening because I have a couple update statements that include colons within a string like this:
UPDATE ADDRESS SET ADDRESS_STREET_LINE1 = 'Moh: Chandawala'...
UPDATE ADDRESS SET ADDRESS_STREET_LINE1 = 'Moh:chandawala'...
So it's treating them like bind variables. I was under the impression that SET DEFINE OFF would make it treat anything within a quoted string as characters and not interpret anything within, including perceived bind variables.
This obviously isn't the case - So in this situation, what am I supposed to do? Do I have to escape these manually?
Thanks.
EDIT - The posted question at When or Why to use a "SET DEFINE OFF" in Oracle Database doesn't help me since that person is trying to escape ampersands for variable substitution, and not colons as bind variables. I'm looking for a way to tell the client to ignore anything (including colons) in quoted strings.
EDIT - Okay, so it sounds like Oracle shouldn't be interpreting that as a bind variable within quotes. So now the question is, why is it doing that?
Set Define Off is a SQLPlus command and it prevents SQLPlus from treating & as a special character. & is also specific to SQLPlus and have no meaning outside it.
When define is on, the SQLPlus replaces the substitution variables with actual values and then pass it to the Oracle SQL engine.
On the other hand, : are real bind variable that only Oracle SQL engine recognises and look for a to-be-bound value. The : are not recognized as bind meta character by SQLPlus and is passed as such to the SQL engine.
I cannot duplicate your issue. I created a table called dually with a column of a single character. When I attempt to run the update statement, no substitution is permitted.
SQL> UPDATE brianl.dually
2 SET dummy = ':x';
SET dummy = ':x'
*
ERROR at line 2:
ORA-12899: value too large for column "BRIANL"."DUALLY"."DUMMY" (actual: 2,
maximum: 1)
Have you tried using concatenation?
UPDATE ADDRESS SET ADDRESS_STREET_LINE1 = 'Moh' || ':' || Chandawala'
using raw SQL when I use the IN statement inside a query using sequel's fetch function, I can't escape a single quote by writing where stuff IN ...
#values='stuff1\'','stuff2\''
db.fetch("query...where IN (?)", "#{#values}")
outputs query...where stuff IN ('stuff1'',''stuff2') instead of ('stuff1','stuff2')
Quite frustrating that I'd probably have to write a Sequel equivalent for the raw query or use a different ORM just because of this escape issue. Any thoughts?
You should probably do something like:
#values = ['stuff1', 'stuff2']
db.fetch("query...where IN ?", #values)
If I understand the Sequel documentation correctly, using String#lit or Sequel.lit should turn a Ruby string into a literal string and bypass the automatic escaping mechanism; therefore, this should work (untested):
#values='stuff1\'','stuff2\''.lit
db.fetch("query...where IN (?)", "#{#values}")
The usual caveats when working with raw SQL strings (SQL injection attacks, inefficient SQL due to forced re-parsing of statements etc.) apply :-)
This works:
values = Sequel.lit("'stuff1', 'stuff2'")
db.fetch("SELECT * FROM TABLE1 WHERE COL1 IN ?", values)
See also: How to pass a list to an IN clause via a placeholder with Ruby Sequel
How can I escape an apostrophe in golang?
I have a string
s = "I've this book"
and I want to make it
s = "I\'ve this book"
How to achieve this?
Thanks in advance.
Escaping a character is only necessary if it can be interpreted in two or more ways. The apostrophe in your string can only be interpreted as an apostrophe, escaping is therefore not necessary as such. This is probably why you see the error message unknown escape sequence: '.
If you need to escape the apostrophe because it is inserted into a database, first consider using library functions for escaping or inserting data directly. Correct escaping has been the culprit of many security problems in the last decades. You will almost certainly do it wrong.
Having said that, you have to escape \ to do what you want (click to play):
fmt.Println("\\'") # outputs \'
As you're using cassandra, you can use packages like gocql which provide you with parametrized queries:
session.Query(`INSERT INTO sometable (text) VALUES (?)`, "'escaping'").Exec();
In my Ruby app, I've used the following method and regular expression to remove all HTML tags from a string:
str.gsub(/<\/?[^>]*>/,"")
This regular expression did just about all I was expecting it to, except it caused all quotation marks to be transformed into “
and all single quotes to be changed to ”
.
What's the obvious thing I'm missing to convert the messy codes back into their proper characters?
Edit: The problem occurs with or without the Regular Expression, so it's clear my problem has nothing to do with it. My question now is how to deal with this formatting error and correct it. Thanks!
Use CGI::unescapeHTML after you perform your regular expression substitution:
CGI::unescapeHTML(str.gsub(/<\/?[^>]*>/,""))
See http://www.ruby-doc.org/core/classes/CGI.html#M000547
In the above code snippet, gsub removes all HTML tags. Then, unescapeHTML() reverts all HTML entities (such as <, “) to their actual characters (<, quotes, etc.)
With respect to another post on this page, note that you will never ever be passed HTML such as
<tag attribute="<value>">2 + 3 < 6</tag>
(which is invalid HTML); what you may receive is, instead:
<tag attribute="<value>">2 + 3 < 6</tag>
The call to gsub will transform the above to:
2 + 3 < 6
And unescapeHTML will finish the job:
2 + 3 < 6
You're going to run into more trouble when you see something like:
<doohickey name="<foobar>">
You'll want to apply something like:
gsub(/<[^<>]*>/, "")
...for as long as the pattern matches.
This regular expression did just about
all I was expecting it to, except it
caused all quotation marks to be
transformed into “ and all
single quotes to be changed to ”
.
This doesn't sound as if the RegExp would be doing this. Are you sure it's different before?
See this question here for information about the problem, it has got an excellent answer:
Get non UTF-8 form fields as UTF-8 in php.
I've run into a similar problem with character changes, this happened when my code ran through another module that enforced UTF-8 encoding and then when it came back, I had a different file (slurped array of lines) on my hands.
You could use a multi-pass system to get the results you are looking for.
After running your regular expression, run an expression to convert &8220; to quotes and another to convert &8221; to single quotes.