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  • Why is selecting specified columns, and all, wrong in Oracle SQL?

    - by TomatoSandwich
    Say I have a select statement that goes.. select * from animals That gives a a query result of all the columns in the table. Now, if the 42nd column of the table animals is is_parent, and I want to return that in my results, just after gender, so I can see it more easily. But I also want all the other columns. select is_parent, * from animals This returns ORA-00936: missing expression. The same statement will work fine in Sybase, and I know that you need to add a table alias to the animals table to get it to work ( select is_parent, a.* from animals ani), but why must Oracle need a table alias to be able to work out the select?

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  • C# underlying types of enums

    - by Marlon
    What is the point of having enum SomeEnum : byte // <---- { SomeValue = 0x01, ... } when you have to make a cast just to assign it to the same type of variable as the enums underlying type? byte b = (byte)SomeEnum.SomeValue;

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  • Is there a standard SQL Table design for overriding 'big picture' default values with lower level de

    - by RichardHowells
    Here's an example. Suppose we are trying to calculate a service charge. Say sales in the USA attract a 10 dollar charge, sales in the UK attract a 20 dollar charge So far it's easy - we are starting to imagine a table that lists charges by country. Now lets assume that Alaska and Hawaii are treated as special cases they are both 15 dollars That suggests a table with states, Alaska and Hawaii are charged at 15, but presumably we need 48 (redundant) rows all saying 10. This gives us a maintainance problem, our user only wants to type 10 once NOT 48 times. It does not sit well with the UK either. The UK does not have states. Suppose we throw in another couple of cross cutting rules. If you order by phone there is a 10% supplement on the charge. If you order via the web there is a 10% discount. But for some reason best known to the owners of the business the web/phone supplement/discount are not applied in Hawaii. It seems to me that this is quite a common kind of problem and there is probably a well known arrangement of tables to store the data. Most cases get handled by broad brush answers, but there are some very detailed low level variations that give rise to a huge number of theoretical combinations, most of which are not used.

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  • How do I create a create and execute an SQL command using OleDB directly?

    - by Pagis
    I want to use the OleDB interfaces directly to open a connection to a DB, create a command and executing it (for example using the ICommandText interface). The main thing I can't find is how to create the connection and the command object and how to connect the object that implements the ICommandText to the connection. In ADO I would just use the ActiveConnection property but I want to do this directly on the OleDB interfaces. Also, if anyone can recommend a tutorial to OleDB, ether online or a book, free or not that would be great (but a tutorial and not just a reference / API) I'm using C++ but any native code would be fine.

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  • How to insert a value based on lookup from another table [SQL]?

    - by Shaitan00
    I need to find a way to do an INSERT INTO table A but one of the values is something that comes from a lookup on table B, allow me to illustrate. I have the 2 following tables: Table A: A1: String A2: Integer value coming from table B A3: More Data Table B: B1: String B2: Integer Value Example row of A: {"Value", 101, MoreData} Example row of B: {"English", 101} Now, I know I need to INSERT the following into A {"Value2", "English", MoreData} but obviously that won't work because it is expecting an Integer in the second column not the word "English", so I need to do a lookup in Table B first. Something like this: INSERT INTO tableA (A1, A2, A3) VALUES ("Value2", SELECT B2 FROM tableB where B1="English", MoreData); Obviously this doesn't work as-is ... Any suggestions?

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  • what's the use of 0 in wait system call?

    - by Supereme
    Hi, The syntax for the wait system call is pid= wait(&var) where pid is the process id of child and var is the variable which will contain the reason for exiting child. But what happens when we use wait((int *)0)? What does it exactly mean? Thank you.

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  • Dynamic SQL Rows & Columns...cells require subsequent query. Best approach?

    - by Pyrrhonist
    I have the following tables below City --------- CityID StateID Name Description Reports --------- ReportID HeaderID FooterID Description I’m trying to generate a grid for use in a .Net control (Gridview, Listview…separate issue about which will be the ‘best’ one to use for my purposes) which will assign the reports as the columns and the cities as the rows. Which cities get displayed is based on the state selected, and is easy enough SELECT * FROM CITIES WHERE STATEID=@StateID However, the user is able to select which reports are being generated for each City (Demographics, Sales, Land Area, etc.). Further, the resultant cells (City * Report) is a sub-query on different tables based on the city selected and the report. Ie. Column Sales selected yields SELECT * FROM SALES WHERE CITYID=@CityID I’ve programmed a VERY inelegant solution using multiple queries and brute-forcing the grid to be created (line by line, row by row creation of data elements), but I’m positive there’s got to be a better way of accomplishing this…? Any / all suggestions appreciated here as the brute force approach I’ve gotten is slow and cumbersome…and this will have to be used often by the client, so I’m not sure it’ll be acceptable in it’s current implementation.

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  • File System Types in .Net

    - by Avi
    I don't get the abstractions and the terminology :-( For example, DirectoryInfo.FullName is defined as the full path of the directory or file, but it's a string! So is DirectoryInfo.Name, FileInfo.FullName, Path.GetDirectoyName and so on. This means that in .Net there is no "depth" (or "meat" - my English isn't so good) for the file system objects. There's no protection from a type system. I can't, for example, define two Path objects and ask if one of them is "above" the other - I have to manipulate the strings. I can't differentiate between a Path that identifies a directory and a path that identifies a file. I can't do anything!-( Just manipulate strings. Is this correct (or am I simply missing something). If correct, are there any alternatives?

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  • Intersection between sets containing different types of variables

    - by Gacek
    Let's assume we have two collections: List<double> values List<SomePoint> points where SomePoint is a type containing three coordinates of the point: SomePoint { double X; double Y; double Z; } Now, I would like to perform the intersection between these two collections to find out for which points in points the z coordinate is eqal to one of the elements of values I created something like that: HashSet<double> hash = new HashSet<double>(points.Select(p=>p.Z)); hash.IntersectWith(values); var result = new List<SomePoints>(); foreach(var h in hash) result.Add(points.Find(p => p.Z == h)); But it won't return these points for which there is the same Z value, but different X and Y. Is there any better way to do it?

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  • Is it a problem if i query again and again to SQL Server 2005 and 2000?

    - by learner
    Window app i am constructing is for very low end machines (Celeron with max 128 RAM). From the following two approaches which one is the best (I don't want that application becomes memory hog for low end machines):- Approach One:- Query the database Select GUID from Table1 where DateTime <= @givendate which is returning me more than 300 thousands records (but only one field i.e. GUID - 300 thousands GUIDs). Now running a loop to achieve next process of this software based on GUID. Second Approach:- Query the database Select Top 1 GUID from Table1 where DateTime <= @givendate with top 1 again and again until all 300 thousands records done. It will return me only one GUID at a time, and I can do my next step of operation. What do you suggest which approach will use the less Memory Resources?? (Speed / performance is not the issue here).

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  • SQL Server 2005: Why would a delete from a temp table hang forever?

    - by Dr. Zim
    DELETE FROM #tItem_ID WHERE #tItem_ID.Item_ID NOT IN (SELECT DISTINCT Item_ID FROM Item_Keyword JOIN Keyword ON Item_Keyword.Keyword_ID = Keyword.Record_ID WHERE Keyword LIKE @tmpKW) The Keyword is %macaroni%. Both temp tables are 3300 items long. The inner select executes in under a second. All strings are nvarchar(249). All IDs are int. Any ideas? I executed it (it's in a stored proc) for over 12 minutes without it finishing.

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  • Add to exisiting db values, rather than overwrite - PDO

    - by sam
    Im trying to add to existing decimal value in table, for which im using the sql below: UPDATE Funds SET Funds = Funds + :funds WHERE id = :id Im using a pdo class to handle my db calls, with the method below being used to update the db, but i couldnt figure out how to amend it to output the above query, any ideas ? public function add_to_values($table, $info, $where, $bind="") { $fields = $this->filter($table, $info); $fieldSize = sizeof($fields); $sql = "UPDATE " . $table . " SET "; for($f = 0; $f < $fieldSize; ++$f) { if($f > 0) $sql .= ", "; $sql .= $fields[$f] . " = :update_" . $fields[$f]; } $sql .= " WHERE " . $where . ";"; $bind = $this->cleanup($bind); foreach($fields as $field) $bind[":update_$field"] = $info[$field]; return $this->run($sql, $bind); }

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  • Are these 2 sql queries equivalent in all respects (e.g. estimated and actual execution plan)?

    - by Xerion
    Are query 1) == 2) in terms of estimated query plan AND actual plan? (can statistics affect the actual plan here, ever?) declare @cat int -- input param from prc ... 1) select * from A as a join B as b on b.id = a.id on b.cat = @cat join C as c on c.fid = b.fid on c.cat = @cat where a.cat = @cat 2) select * from A as a join B as b on b.id = a.id on b.cat = a.cat join C as c on c.fid = b.fid on c.cat = b.cat where a.cat = @cat It seems to me that these should logically be equivalent and the execution plan should always be the same regardless of actual difference in tables. And adding more conditions either in join, or where, or add more tables to join shouldn't change this. Are there cases this is not true?

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  • WTF why does this SQL work in VS but not in CODE?

    - by acidzombie24
    The line cmd.ExecuteNonQuery(); cmd.CommandText CREATE TRIGGER subscription_trig_0 ON subscription AFTER INSERT AS UPDATE user_data SET msg_count=msg_count+1 FROM user_data JOIN INSERTED ON user_data.id = INSERTED.recipient; The exception: Incorrect syntax near the keyword 'TRIGGER'. Then using VS 2010, connected to the very same file (a mdf file) i run the query above and i get a success message. WTF!

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  • How to group rows into two groups in sql?

    - by user1055638
    Lets say I have such a table: id|time|operation 1 2 read 2 5 write 3 3 read 4 7 read 5 2 save 6 1 open and now I would like to do two things: Divide all these records into two groups: 1) all rows where operation equals to "read" 2) all other rows. Sum the time in each group. So that my query would result only into two rows. What I got so far is: select sum(time) as total_time, operation group by operation ; Although that gives me many groups, depending on the number of distinct operations. How I could group them only into two categories? Cheers!

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  • MYSQL - SQL query Getting single record for the similar records and populating other columns with which has more length

    - by Bujji
    Here is my case , I have a database table with below fields name place_code email phone address details estd others and example data if you look at the above example table First three records are talking about XYZ and place code 1020 . I want create a single record for these three records based on substring(name,1,4) place_code ( I am lucky here for all the similar records satisfies this condition and unique in the table .) For the other columns which record column length has max . For example again for the above 3 records email should be [email protected] , phone should be 657890 and details should be "testdetails" This should be done for all the table . (Some has single records and some has max 10 records ) Any help on query that helps me to get the desired result ? Thank You Regards Kiran

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  • SQL -- How is DISTINCT so fast without an index?

    - by Jonathan
    Hi, I have a database with a table called 'links' with 600 million rows in it in SQLite. There are 2 columns in the database - a "src" column and a "dest" column. At present there are no indices. There are a fair number of common values between src and dest, but also a fair number of duplicated rows. The first thing I'm trying to do is remove all the duplicate rows, and then perform some additional processing on the results, however I've been encountering some weird issues. Firstly, SELECT * FROM links WHERE src=434923 AND dest=5010182. Now this returns one result fairly quickly and then takes quite a long time to run as I assume it's performing a tablescan on the rest of the 600m rows. However, if I do SELECT DISTINCT * FROM links, then it immediately starts returning rows really quickly. The question is: how is this possible?? Surely for each row, the row must be compared against all of the other rows in the table, but this would require a tablescan of the remaining rows in the table which SHOULD takes ages! Any ideas why SELECT DISTINCT is so much quicker than a standard SELECT?

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  • Testing variable types in Python

    - by Jasper
    Hello, I'm creating an initialising function for the class 'Room', and found that the program wouldn't accept the tests I was doing on the input variables. Why is this? def __init__(self, code, name, type, size, description, objects, exits): self.code = code self.name = name self.type = type self.size = size self.description = description self.objects = objects self.exits = exits #Check for input errors: if type(self.code) != type(str()): print 'Error found in module rooms.py!' print 'Error number: 110' elif type(self.name) != type(str()): print 'Error found in module rooms.py!' print 'Error number: 111' elif type(self.type) != type(str()): print 'Error found in module rooms.py!' print 'Error number: 112' elif type(self.size) != type(int()): print 'Error found in module rooms.py!' print 'Error number: 113' elif type(self.description) != type(str()): print 'Error found in module rooms.py!' print 'Error number: 114' elif type(self.objects) != type(list()): print 'Error found in module rooms.py!' print 'Error number: 115' elif type(self.exits) != type(tuple()): print 'Error found in module rooms.py!' print 'Error number: 116' When I run this I get this error: Traceback (most recent call last): File "/Users/Jasper/Development/Programming/MyProjects/Game Making Challenge/Europa I/rooms.py", line 148, in <module> myRoom = Room(101, 'myRoom', 'Basic Room', 5, '<insert description>', myObjects, myExits) File "/Users/Jasper/Development/Programming/MyProjects/Game Making Challenge/Europa I/rooms.py", line 29, in __init__ if type(self.code) != type(str()): TypeError: 'str' object is not callable

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  • Compiler error when using abstract types

    - by Dylan
    I'm trying to implement a "protocol helper" trait that is responsible for matching up Prompts and Responses. The eventual goal is to have an object that defines the various Prompt and Response classes as subclasses of a sealed trait, then have a class that mixes in the ProtocolSupport trait for that Protocol object. The problem is that my current approach won't compile, even though I'm fairly sure it should. Here's a distilled version of what I've got: trait Protocol { type Response type Prompt <: BasePrompt trait BasePrompt { type Data def validate(response: Response): Validated[Data] } } trait ProtocolSupport[P <: Protocol] { def foo(prompt: P#Prompt, response: P#Response) = { // compiler error prompt.validate(response) } } The compiler doesn't like the response as an argument to prompt.validate: [error] found : response.type (with underlying type P#Response) [error] required: _4.Response where val _4: P [error] prompt.validate(response) [error] ^ This isn't very helpful.. it seems to say that it wants a P.Response but that's exactly what I'm giving it, so what's the problem?

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