I don't currently have any access to any Oracle books and my searches online are returning literally no results ( (+) in Google shows nothing). I'm looking through existing code to add some fields to a query and saw:
AND lookup.LookupID (+) = AuditID
However, I have no idea what this does. Any help would be appreciated.
Note: I'm not seeing a community wiki checkbox while posting this in Google Chrome, so if someone can change it to that for me, I'd be appreciative. Thanks.
What you're seeing is an "old" way for specifying an outer join. Oracle needed a syntax to represent outer joins and before the ANSI commitee settled on a standard syntax, Oracle came up with their own.
(+) should be seen only in legacy code and today it is recommended to simply avoid this syntax and stick with the standards.
In this Oracle FAQ you can read some historical info. Not too detailed, but it will give you an idea of how this operator came to be.
Relevant part:
In query2 we see the "Old Style"
Oracle syntax for OUTER-JOIN. It is
the PLUS SIGN in parenthesis. This
syntax was not actually invented by
Oracle but rather some smart guy whose
name escapes me at the moment. Oracle
saw its value and was an early adopter
of OUTER-JOIN but doing so required
them to use a syntax before ANSI SQL
COMMITTEE settled on one. The new and
improved ANSI SQL is fine and all,
some say even better, but being an old
bird I tend to stick with old and
proven ways till something makes me
change.
Apparently not even Oracle did invent this syntax. It's good to have standards...
It is Oracle way to specify a outer join (ANSI way would be RIGHT JOIN/LEFT JOIN)
Related
It appears that SQLite, apparently as a "compatibility feature", parses double quoted identifiers as string literals if no matching column is found.
I understand that it does so for people who write improper sql, and for backwards compatibility with legacy projects created by such people, but it makes debugging very difficult for those of us writing proper sql on brand new projects.
For example,
SELECT * FROM "users" WHERE "usernme" = 'joe';
returns a query with 0 rows, since the string 'usernme' does not equal the string 'joe'.
This leaves me scratching my head wondering why i'm not getting joe's row even when i know there's a user by that name until I painstakingly backtrack my code and realize that I left out an a.
Is there any "strict mode" PRAGMA or API option to enforce quoting rules and treat all double-quoted strings as identifiers so that it will inform me immediately if one is misspelled?
(And please, no answers telling me not to quote identifiers if I don't need to, because any such answer is basically telling me that in order to get proper debugging, you have to write bad code in the first place.)
This is hardcoded in the SQLite parser and cannot be changed from the outside.
I also asked in the SQLite channel and someone there was kind enough to look through the source code and create a patch, and even started a thread on the mailing list describing the patch:
http://www.mail-archive.com/sqlite-users#sqlite.org/msg73832.html
It's not an answer that works for the official builds, but it may be someday. For the moment, I'm just going to recompile it myself with this patch.
Ten years later, and this doesn't completely meet your criteria about "strict mode" kinds of things, but here's a trick I used to make some queries safer, if you can remember to use it. It's to give your table an alias and reference it:
SELECT t."nosuch_column" FROM some_table t;
I suppose in this form, it's clear to SQLite that a literal isn't desired.
In my SQLite 3 Database, I have some records with Turkish characters such as "Ö", "Ü", "İ" etc. When I select my values with SELECT * FROM TABLE ORDER BY COLUMN_NAME query, the records that begin with these characters are coming at the end.
Normally, they should've come after the letter that is dot-less version of each. Like "Ö" is after "O", "Ü" is after "U".
Is it something about regional settings? Is there a way to control these settings?
I use SQLite Manager in Firefox to manage my DB.
Thanks in advance.
P.S. I know it's not a solution for SQLite but for those who need to use SQLite DB in Objective-C, they can sort the data array after getting from SQLite DB. Here's a good solution: How to sort an NSMutableArray with custom objects in it?
Unfortunately, it seems there's no direct solution for this. For iOS at least. But there are ways to follow.
After I subscribed to mailing list of SQLite, user Named Jean-Christophe Deschamps came with this reply:
"In my SQLite 3 Database, I have some records with Turkish characters
such as "Ö", "Ü", "İ" etc. When I select my values with 'SELECT * FROM
TABLE ORDER BY COLUMN_NAME' query, the records that begin with these
characters are coming at the end."
Bare bone SQLite only collates correctly on the lower ASCII charset.
While that's fine for plain english, it doesn't work for most of us.
"Normally, they should've come after the letter that is dot-less
version of each. Like "Ö" is after "O", "Ü" is after "U". Is it
something about regional settings? Is there a way to control these
settings?"
You have the choice among some ways to get it right or close to right
for your language(s):
o) use ICU either as an extension (for third-party managers) or
linked to
your application.
Advantages: it works 100% correctly for a given language at a time in each
operation.
Drawbacks: it's huge and slow and it requires you register a collation for
every language you deal with. Also it won't work well for columns
containing several non-english languages.
o) write your own collation(s) invoking your OS' ICU routines to
collate
strings.
Advantages: doesn't bloat your code with huge libraries.
Drawbacks: requires you write this extension (in C or something), same
other drawbacks as ICU.
o) If you use Windows, download and use the functions in the
extension I
wrote for a close-to-correct result.
Advantages: it's small, fairly fast and ready to use, it is language-
independant yet works decently well for many languages at
the same time; it also offers a number of Unicode-aware
string manipulation functions (unaccenting or not) functions,
a fuzzy search function and much more. Comes as a C source and
x86 DLL, free for any purpose.
Drawback: it probably doesn't work 100% correctly for any language using
more than "vanilla english letters": your dotless i will collate
along dotted i, for instance. It's a good compromise between
absolute correctness for ONE language and "fair" correctness for
most languages (including some asian languages using diacritics)
Download: http://dl.dropbox.com/u/26433628/unifuzz.zip
"I use SQLite Manager in Firefox to manage my DB."
My little extension will work with this one. You might also want to
try SQLite Expert which has ICU built-in (at least in its Pro version)
and much more.
It could be the regional settings but first I would verify UTF-8 encoding is being used.
I am trying to hash out a strategy for implementing a very simple site search in ASP.NET MVC and SQL Server 2008.
Really, all I want to to do is to be able to rank search results based on the number of times a search word or phrase is found in the webpage. I attempted to do this using LINQtoSQL but I ran into a lot of issues where some LINQ commands don't have a SQL equivalent. This was a few months ago so I don't remember specific errors.
So, I'm just trying to figure out an approach. What I'm thinking is this:
Approach 1:
I should probably write a program to spider the site and somehow index the site's text - I'm thinking I should save information in a table like:
ID
Word
URL
I could then query that and rank based on how many time that word is associated with a certain URL. But then I realized that this technique would completely breakdown if a user was searching for a phrase.
Approach 2:
Then I was toying with the idea of using SPROCs to create a temporary table with a record for each URL that would somehow parse the text and determine how many times the phrase or word appeared in each individual URL. and then we would return the results from the temp table. I am thinking the temporary table would look something like this:
ID
SearchText
URL
Frequency
And then select * from temptable order by Frequency asc or something like that.
However, I'm not sure if SPROCs are capable of parsing text like that, or if simultanious searching would be possible.
I am looking for something very lightweight. I'm not really interested in using Lucene or Solr or anything like that because the learning curve seems very steep and those applications' features are far away more than what I need.
Any thoughts on how I should approach this problem? Is there a different approach that I should consider?
For your phrase versus word issue, why not use wildcards and LIKE operators?
Select Count(*) from temptable where SearchPhrase LIKE '%Apple%'
Maybe not exactly what you want, but Windows SharePoint Search Server isn't all that bad.
Yes, it has the word 'SharePoint' in it, which would usually make me grab the scissors on my desk and start stabbing my eyes out, but having to use it once in a pinch, I was actually somewhat impressed with it.
It's free, so maybe worth a couple of hours playing with it for comparison to writing something custom.
After a little poking around, it looks like SQL Server 2008's Full Text Search is what I would want to use. I'm not 100% sure yet, but it looks promising.
http://msdn.microsoft.com/en-us/library/ms142547.aspx
If you're considering Full Text Search, then also check out lucene.net.
I used FTS for one project, and later used lucene.net for another, and although the requirements were different from yours, I'd never go back to FTS now.
I'm trying to build a search that is similar to that on Google (with regards to exact match encapsulated in double quotes).
Let's use the following phrase for an example
"phrase search" single terms [different phrase]
Currently if I use the following code
Dim searchTermsArray As String() = searchTerms.Split(New String() {" ", ",", ";"}, StringSplitOptions.RemoveEmptyEntries)
For Each entry In searchTermsArray
Response.Write(entry & "<br>")
Next
my output is
"phrase
search"
single
terms
[different
phrase]
but what I really need is to build a key value pair
phrase search | table1
single | table1
terms | table1
different phrase | table2
where table1 is a table with general info, and table2 is a table of "tags" similar to that on stackoverflow.
Can anybody point me in the right direction on how to properly capture the input?
What are you trying to do is not that trivial. Implementing a search "similar to Google's" is far beyond parsing the search string.
I'd suggest you not to reinvent the wheel and instead use production ready solutions such as Apache Lucene.NET or Apache Solr. Those cope with both parsing and fulltext search.
But if you only need to parse this kind of strings then you should really consider solution Pete pointed to.
Regex is your friend. See this question
Depending on how fancy you plan in getting, you might consider the search grammar/implementation that's included with Irony.
http://irony.codeplex.com/
Search string parsing is a non-regular problem. That means that while a regular expression can get deceptively close, it won't take you all the way there without using proprietary extensions, building an unmaintainable mess of an expression, leaving nasty edge cases open that don't work how you'd like, or some combination of the three.
Instead, there are three correct ways to handle this:
Use a third-party solution like Lucene.
Build a grammar via something like antlr.
Build your own state machine.
For a problem of this level (and assuming that search is core enough to what you're doing to really want to implement it yourself), I'd probably go with option 3. This makes more sense when you realize that regular expressions are themselves instructions for how to set up state machines. All you're doing is building that right into your code. This should give you the ability to tune performance and features as well, without requiring adding a larger lexer component into your code.
For an example of how you might do this take a look at my answer to this question:
Reading CSV files in C#
hat I would do is build a state machine to parse the string character by character. This will be the easiest way to implement a fully-correct solution, and should also result in the fastest code.
I'm currently looking at a terrible legacy ColdFusion app written with very few stored procedures and lots of nasty inline SQL statements (it has a similarly bad database too).
Does anyone know of any app which could be used to search the files of the app picking out any SQL statements and listing the tables/stored procedures which are referenced?
Dreamweaver will allow you to search the code of the entire site. If the site is setup properly including the RDS password and provide a data source it can tell you a lot of information. I've only set it up once so I can't remember exactly what information it gives you, I think maybe just the DB structure. Application window > databases. Even if it isn't set up properly just searching for "cfquery" will quickly find all your queries.
You could also write a CF script using CFDirectory/CFFile to loop the .cfm files and parse everything between cfquery and /cfquery tags.
CFBuilder may have some features like that but I'm not to familiar with it yet.
edit I've heard that CFBuilder can't natively find all your cfqueries that don't have cfqueryparam but you can use CF to extend CFB to do so. I imagine you could find/write something for CFB to help you with your problem.
another edit
I know it isn't indexing the contents of the query, but you can use regex to search using the editor as well. searching for <cfquery.+(select|insert|update|delete) checking the regex box should find the queries that aren't using cfstoredProc (be sure to uncheck the match case option if there is one). I know Dreamweaver and Eclipse can both search for Regex.
HTH
As mentioned above I would try a grep with a regex looking for
"<cfquery*" "</cfquery>" and "<cfstoredproc*" "</cfstoredproc>"
In addition if you have tests that have good code coverage or even just feel like the app is fully exercised in production you could try turning on "Log Database Calls" in Admin - > Datasources or maybe even at the JDBC driver level, just monitor performance to make sure it does not slow the site down unacceptably.
In short: no. You'd have to do alot of tricky parsing to make sure you get all the SQL. And because you can glob SQL together from lots of strings, you'll almost always miss some of it.
The best you're likely to do will be a case insensitive grep for "SELECT|INSERT|UPDATE|DELETE" and then manually pulling out the table names.
Depending on how the code is structured, you might be able to get the table names by regexing the SQL from clause. But that's not foolproof. Alot of people use string concatenation to build SQL statements. This is bad because it can introduce SQL injection attacks, and it also make this particular problem harder.