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• Round date to fiscal year

  - by Dave Jarvis

  The following database view rounds the date back to the closest fiscal year (April 1st): CREATE OR REPLACE VIEW FISCAL_YEAR_VW AS SELECT CASE WHEN to_number(to_char( SYSDATE, 'MM' )) < 4 THEN to_date('1-APR-'||to_char(add_months(SYSDATE, -12), 'YYYY'), 'dd-MON-yyyy') ELSE to_date('1-APR-'||to_char(SYSDATE, 'YYYY'), 'dd-MON-yyyy') END AS fiscal_year FROM dual; This allows us to calculate the current fiscal year based on today's date. How can this calculation be simplified or optimized?

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• JSON VIEW using GROUP_CONCAT question

  - by Dan Beam

  Hey DBAs and overall smart dudes. I have a question for you. We use MySQL VIEWs to format our data as JSON when it's returned (as a BLOB), which is convenient (though not particularly nice on performance, but we already know this). But, I can't seem to get a particular query working right now (each row contains NULL when it should contain a created JSON object with the values of multiple JOINs). Here's the general idea: SELECT CONCAT( "{", "\"some_list\":[", GROUP_CONCAT( DISTINCT t1.id ), "],", "\"other_list\":[", GROUP_CONCAT( DISTINCT t2.id ), "],", "}" ) cool_json FROM table_name tn INNER JOIN ( some_table st ) ON st.some_id = tn.id LEFT JOIN ( another_table at, another_one ao, used_multiple_times t1 ) ON st.id = at.some_id AND at.different_id = ao.different_id AND ao.different_id = t1.id LEFT JOIN ( another_table2 at2, another_one2 ao2, used_multiple_times t2 ) ON st.id = at2.some_id AND at2.different_id = ao2.different_id AND ao2.different_id = t2.id GROUP BY tn.id ORDER BY tn.name Anybody know the problem here? Am I missing something I should be grouping by? It was working when I was only doing 1 LEFT JOIN & GROUP_CONCAT, but now with multiple JOINs / GROUP_CONCATs it's messing it up. When I move the GROUP_CONCATs from the "cool_json" field they work as expected, but I'd like my data formatted as JSON so I can decode it server-side or client-side in one step.

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• using "in" with a case statement

  - by magic1

  Hi Is it possible to write something like Case when a in (value1,value2) then b else a end

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• SQL2008 merge replication fails to update depdendent items when table is added

  - by Dan Puzey

  Setup: an existing SQL2008 merge replication scenario. A large server database, including views and stored procs, being replicated to client machines. What I'm doing: * adding a new table to the database * mark the new table for replication (using SP_AddMergeArticle) * alter a view (which is already part of the replicated content) is updated to include fields from this new table (which is joined to the tables in the existing view). A stored procedure is similarly updated. The problem: the table gets replicated to client machines, but the view is not updated. The stored procedure is also not updated. Non-useful workaround: if I run the snapshot agent after calling SP_AddMergeArticle and before updating the view/SP, both the view and the stored procedure changes correctly replicate to the client. The bigger problem: I'm running a list of database scripts in a transaction, as part of a larger process. The snapshot agent can't be run during a transaction, and if I interrupt the transaction (e.g. by running the scripts in multiple transactions), I lose the ability to roll back the changes should something fail. Does anyone have any suggestions? It seems like I must be missing something obvious, because I don't see why the changes to the view/sproc wouldn't be replicating anyway, regardless of what's going on with the new table.

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• C# : DBConnection.Open() timeout is too long.

  - by leo

  Hi, I'm trying to connect to a server that the user inputs. When the server doesn't exist, I'd like to give a quick feedback to the end-user so he can correct what he's typed. Is there any way to test if a server exists before trying to connect ? Thanks

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• Porting join from Oracle to Postgres

  - by Grasper

  INSERT INTO MISSION_OBJECTIVE( MSN_INT_ID, MO_INT_ID, MO_MSN_CLASS_NM, MO_MSN_CLASS_CD, MO_MSN_TYPE, MO_PRIORITY, MO_COMMENT, MO_START_DT, MO_END_DT, ASP_AIRSPACE_NM, MO_OBJ_LOCATION, MO_ALO_LEG_ID, MO_ALO_ARRIVE_LOC) SELECT '1025', '1', 'AIRDROP', 'ADP', 'LAPES', NULL, COALESCE( NULL, ' '), TO_TIMESTAMP( '1002260900', 'YYMMDDHH24MI'), TO_TIMESTAMP( '1002260915', 'YYMMDDHH24MI'), 'TRANSIT ALPHA', 'TRANSIT ALPHA', '1', 'TRANSIT ALPHA' FROM AIRSPACE ASP, apsmain .MISSION_CLASS MC WHERE ASP.ASP_AIRSPACE_NM(+)= 'TRANSIT ALPHA' AND MC.MCS_MISSION_CLASS_NAME= 'AIRDROP' AND 'TRANSIT ALPHA' IS NOT NULL Is that exactly the same as: INSERT INTO MISSION_OBJECTIVE( MSN_INT_ID, MO_INT_ID, MO_MSN_CLASS_NM, MO_MSN_CLASS_CD, MO_MSN_TYPE, MO_PRIORITY, MO_COMMENT, MO_START_DT, MO_END_DT, ASP_AIRSPACE_NM, MO_OBJ_LOCATION, MO_ALO_LEG_ID, MO_ALO_ARRIVE_LOC) SELECT '1025', '1', 'AIRDROP', 'ADP', 'LAPES', NULL, COALESCE( NULL, ' '), TO_TIMESTAMP( '1002260900', 'YYMMDDHH24MI'), TO_TIMESTAMP( '1002260915', 'YYMMDDHH24MI'), 'TRANSIT ALPHA', 'TRANSIT ALPHA', '1', 'TRANSIT ALPHA' FROM AIRSPACE ASP, apsmain .MISSION_CLASS MC WHERE ASP.ASP_AIRSPACE_NM = 'TRANSIT ALPHA' AND MC.MCS_MISSION_CLASS_NAME= 'AIRDROP' AND 'TRANSIT ALPHA' IS NOT NULL I just deleted the (+). The part that is confusing me is that ASP.ASP_AIRSPACE_NM is being right joined to a constant.

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• MySQL - Finding time overlaps

  - by Jude

  Hi, I have 2 tables in the database with the following attributes: Booking ======= booking_id booking_start booking_end resource_booked =============== booking_id resource_id The second table is an associative entity between "Booking" and "Resource" (i.e., 1 booking can contain many resources). Attributes booking_start and booking_end are timestamps with date and time in it. May I know how I might be able to find out for each resource_id (resource_booked) if the date/time overlaps or clashes with other bookings of similar resource_id? I was doodling the answer on paper, pictorially, to see if it might help me visualize how I could solve this and I got this: Joining the 2 tables (Booking, Booked_resource) into one table with the 4 attributes needed. Follow the answer suggested here : http://stackoverflow.com/questions/689458/find-overlapping-date-time-rows-within-one-table I did step 1 but step 2 is leaving me baffled! I would really appreciate any help on this! Thanks!

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• "Attach or Add an entity that is not new...loaded from another DataContext. This is not supported."

  - by sah302

  Similar error as other questions, but not quite the same, I am not trying to attach anything. What I am trying to do is insert a new row into a linking table, specifically UserAccomplishment. Relations are set in LINQ to User and Accomplishment Tables. I have a generic insert function: Public Function insertRow(ByVal entity As ImplementationType) As Boolean If entity IsNot Nothing Then Dim lcfdatacontext As New LCFDataContext() Try lcfdatacontext.GetTable(Of ImplementationType)().InsertOnSubmit(entity) lcfdatacontext.SubmitChanges() lcfdatacontext.Dispose() Return True Catch ex As Exception Return False End Try Else Return False End If End Function If you try and give UserAccomplishment the two appropriate objects this will naturally crap out if either the User or Accomplishment already exist. It only works when both user and accomplishment don't exist. I expected this behavior. What does work is simply giving the userAccomplishment object a user.id and accomplishment.id and populating the rest of the fields. This works but is kind of awkward to use in my app, it would be much easier to simply pass in both objects and have it work out what already exists and what doesn't. Okay so I made the following (please ignore the fact that this is horribly inefficient because I know it is): Public Class UserAccomplishmentDao Inherits EntityDao(Of UserAccomplishment) Public Function insertLinkerObjectRow(ByVal userAccomplishment As UserAccomplishment) Dim insertSuccess As Boolean = False If Not userAccomplishment Is Nothing Then Dim userDao As New UserDao() Dim accomplishmentDao As New AccomplishmentDao() Dim user As New User() Dim accomplishment As New Accomplishment() 'see if either object already exists in db' user = userDao.getOneByValueOfProperty("Id", userAccomplishment.User.Id) accomplishment = accomplishmentDao.getOneByValueOfProperty("Id", userAccomplishment.Accomplishment.Id) If user Is Nothing And accomplishment Is Nothing Then 'neither the user or the accomplishment exist, both are new so insert them both, typical insert' insertSuccess = Me.insertRow(userAccomplishment) ElseIf user Is Nothing And Not accomplishment Is Nothing Then 'user is new, accomplishment is not new, so just insert the user, and the relation in userAccomplishment' Dim userWithExistingAccomplishment As New UserAccomplishment(userAccomplishment.User, userAccomplishment.Accomplishment.Id, userAccomplishment.LastUpdatedBy) insertSuccess = Me.insertRow(userWithExistingAccomplishment) ElseIf Not user Is Nothing And accomplishment Is Nothing Then 'user is not new, accomplishment is new, so just insert the accomplishment, and the relation in userAccomplishment' Dim existingUserWithAccomplishment As New UserAccomplishment(userAccomplishment.UserId, userAccomplishment.Accomplishment, userAccomplishment.LastUpdatedBy) insertSuccess = Me.insertRow(existingUserWithAccomplishment) Else 'both are not new, just add the relation' Dim userAccomplishmentBothExist As New UserAccomplishment(userAccomplishment.User.Id, userAccomplishment.Accomplishment.Id, userAccomplishment.LastUpdatedBy) insertSuccess = Me.insertRow(userAccomplishmentBothExist) End If End If Return insertSuccess End Function End Class Alright, here I basically check if the supplied user and accomplishment already exists in the db, and if so call an appropriate constructor that will leave whatever already exists empty, but supply the rest of the information so the insert can succeed. However, upon trying an insert: Dim result As Boolean = Me.userAccomplishmentDao.insertLinkerObjectRow(userAccomplishment) In which the user already exists, but the accomplishment does not (the 99% typical scenario) I get the error: "An attempt has been made to Attach or Add an entity that is not new, perhaps having been loaded from another DataContext. This is not supported." I have debugged this multiple times now and am not sure why this is occuring, if either User or Accomplishment exist, I am not including it in the final object to try to insert. So nothing appears to be attempted to be added. Even in debug, upon insert, the object was set to empty. So the accomplishment is new and the user is empty. 1) Why is it still saying that and how can I fix it ..using my current structure 2) Pre-emptive 'use repository pattern answers' - I know this way kind of sucks in general and I should be using the repository pattern. However, I can't use that in the current project because I don't have time to refactor that due to my non existence knowledge of it and time constraints. The usage of the app is going to so small that the inefficient use of datacontext's and what have you won't matter so much. I can refactor it once it's up and running, but for now I just need to 'push through' with my current structure. Edit: I also just tested this when having both already exists, and only insert each object's IDs into the table, that works. So I guess I could manually insert whichever object doesn't exist as a single insert, then put the ids only into the linking table, but I still don't know why when one object exists, and I make it empty, it doens't work.

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• SQLce Select query problem

  - by DieHard

  Wrote a Truck show Contest voting app, financial etc using sqlite. decided to write backup app for show day using ce 3.5. Created db moved to data directory, created tables configured dgridviews all is well. Entered some test data started management studio 08 ran select query against table and got null returns. Started app from vs studio and found that test data is gone. Re entered data ran query in MS data gone again. If I use VS Studio can start and enter data, close app restart and data is still there, seems only when using outside tool on select query data deletes. I don't know ce that well but this cannot be right. select * from votes = delete * from votes??????????????

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• Insert a datetime value with GetDate() function to a SQL server (2005) table?

  - by David.Chu.ca

  I am working (or fixing bugs) on an application which was developed in VS 2005 C#. The application saves data to a SQL server 2005. One of insert SQL statement tries to insert a time-stamp value to a field with GetDate() TSQL function as date time value. Insert into table1 (field1, ... fieldDt) values ('value1', ... GetDate()); The reason to use GetDate() function is that the SQL server may be at a remove site, and the date time may be in a difference time zone. Therefore, GetDate() will always get a date from the server. As the function can be verified in SQL Management Studio, this is what I get: SELECT GetDate(), LEN(GetDate()); -- 2010-06-10 14:04:48.293 19 One thing I realize is that the length is not up to the milliseconds, i.e., 19 is actually for '2010-06-10 14:04:48'. Anyway, the issue I have right now is that after the insert, the fieldDt actually has a date time value up to minutes, for example, '2010-06-10 14:04:00'. I am not sure why. I don't have permission to update or change the table with a trigger to update the field. My question is that how I can use a INSERT T-SQL to add a new row with a date time value ( SQL server's local date time) with a precision up to milliseconds?

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• A better way to build this MySQL statement with subselects

  - by Corey Maass

  I have five tables in my database. Members, items, comments, votes and countries. I want to get 10 items. I want to get the count of comments and votes for each item. I also want the member that submitted each item, and the country they are from. After posting here and elsewhere, I started using subselects to get the counts, but this query is taking 10 seconds or more! SELECT `items_2`.*, (SELECT COUNT(*) FROM `comments` WHERE (comments.Script = items_2.Id) AND (comments.Active = 1)) AS `Comments`, (SELECT COUNT(votes.Member) FROM `votes` WHERE (votes.Script = items_2.Id) AND (votes.Active = 1)) AS `votes`, `countrys`.`Name` AS `Country` FROM `items` AS `items_2` INNER JOIN `members` ON items_2.Member=members.Id AND members.Active = 1 INNER JOIN `members` AS `members_2` ON items_2.Member=members.Id LEFT JOIN `countrys` ON countrys.Id = members.Country GROUP BY `items_2`.`Id` ORDER BY `Created` DESC LIMIT 10 My question is whether this is the right way to do this, if there's better way to write this statement OR if there's a whole different approach that will be better. Should I run the subselects separately and aggregate the information?

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• Problem with nested lambda expressions.

  - by Lehto

  Hey I'm trying to do a nested lambda expression like to following: textLocalizationTable.Where( z => z.SpokenLanguage.Any( x => x.FromCulture == "en-GB") ).ToList(); but i get the error: Member access 'System.String FromCulture' of 'DomainModel.Entities.SpokenLanguage' not legal on type 'System.Data.Linq.EntitySet`1[DomainModel.Entities.SpokenLanguage]. TextLocalization has this relation to spokenlanguage: [Association(OtherKey = "LocalizationID", ThisKey = "LocalizationID", Storage = "_SpokenLanguage")] private EntitySet<SpokenLanguage> _SpokenLanguage = new EntitySet<SpokenLanguage>(); public EntitySet<SpokenLanguage> SpokenLanguage { set { _SpokenLanguage = value; } get { return _SpokenLanguage; } } Any idea what is wrong?

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• How to define a query om a n-m table

  - by user559889

  Hi, I have some troubles defining a query. I have a Product and a Category table. A product can belong to multiple categories and vice versa so there is also a Product-Category table. Now I want to select all products that belong to a certain category. But if the user does not provide a category I want all products. I try to create a query using a join but this results in the product being selected multiple times if it belongs to multiple categories (in the case no specific category is queried). What kind of query do I have to create? Thanks

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• MySQL Column Value Pivot

  - by manyxcxi

  I have a MySQL InnoDB table laid out like so: id (int), run_id (int), element_name (varchar), value (text), line_order, column_order `MyDB`.`MyTable` ( `id` bigint(20) NOT NULL, `run_id` int(11) NOT NULL, `element_name` varchar(255) NOT NULL, `value` text, `line_order` int(11) default NULL, `column_order` int(11) default NULL It is used to store data generated by a Java program that used to output this in CSV format, hence the line_order and column_order. Lets say I have 2 entries (according to the table description): 1,1,'ELEMENT 1','A',0,0 2,1,'ELEMENT 2','B',0,1 I want to pivot this data in a view for reporting so that it would look like more like the CSV would, where the output would look this: --------------------- |ELEMENT 1|ELEMENT 2| --------------------- | A | B | --------------------- The data coming in is extremely dynamic; it can be in any order, can be any of over 900 different elements, and the value could be anything. The Run ID ties them all together, and the line and column order basically let me know where the user wants that data to come back in order.

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• Db2 sql dump tools

  - by adisembiring

  I am searching for tools to dump db2 tables (like sqlyog or MySQL browser in MySQL). Can you suggest me some? Thanks

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• Data Modeling of Entity with Attributes

  - by StackOverflowNewbie

  I'm storing some very basic information "data sources" coming into my application. These data sources can be in the form of a document (e.g. PDF, etc.), audio (e.g. MP3, etc.) or video (e.g. AVI, etc.). Say, for example, I am only interested in the filename of the data source. Thus, I have the following table: DataSource Id (PK) Filename For each data source, I also need to store some of its attributes. Example for a PDF would be "numbe of pages." Example for audio would be "bit rate." Example for video would be "duration." Each DataSource will have different requirements for the attributes that need to be stored. So, I have modeled "data source attribute" this way: DataSourceAttribute Id (PK) DataSourceId (FK) Name Value Thus, I would have records like these: DataSource->Id = 1 DataSource->Filename = 'mydoc.pdf' DataSource->Id = 2 DataSource->Filename = 'mysong.mp3' DataSource->Id = 3 DataSource->Filename = 'myvideo.avi' DataSourceAttribute->Id = 1 DataSourceAttribute->DataSourceId = 1 DataSourceAttribute->Name = 'TotalPages' DataSourceAttribute->Value = '10' DataSourceAttribute->Id = 2 DataSourceAttribute->DataSourceId = 2 DataSourceAttribute->Name = 'BitRate' DataSourceAttribute->Value '16' DataSourceAttribute->Id = 3 DataSourceAttribute->DataSourceId = 3 DataSourceAttribute->Name = 'Duration' DataSourceAttribute->Value = '1:32' My problem is that this doesn't seem to scale. For example, say I need to query for all the PDF documents along with thier total number of pages: Filename, TotalPages 'mydoc.pdf', '10' 'myotherdoc.pdf', '23' ... The JOINs needed to produce the above result is just too costly. How should I address this problem?

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• Submitting changes to 2 tables with C# linq only one table is changing

  - by Laurence Burke

  SO I am changing the values in 2 different tables and the only table changing is the address table any one know why? protected void btnSubmit_Click(object sender, EventArgs e) { TestDataClassDataContext dc = new TestDataClassDataContext(); var addr = (from a in dc.Addresses where a.AddressID == Convert.ToInt32(ddlAddList.SelectedValue) select a).FirstOrDefault(); var caddr = (from ca in dc.CustomerAddresses where addr.AddressID == ca.AddressID select ca).FirstOrDefault(); if (txtZip.Text != "" && txtAdd1.Text != "" && txtCity.Text != "") { addr.AddressLine1 = txtAdd1.Text; addr.AddressLine2 = txtAdd2.Text; addr.City = txtCity.Text; addr.PostalCode = txtZip.Text; addr.StateProvinceID = Convert.ToInt32(ddlState.SelectedValue); caddr.AddressTypeID = Convert.ToInt32(ddlAddrType.SelectedValue); dc.SubmitChanges(); lblErrMsg.Visible = false; lblSuccess.Visible = true; } else { lblErrMsg.Text = "Invalid Input"; lblErrMsg.Visible = true; } }

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• Cannot open database "test" requested by the login. The login failed. Login failed for user 'xyz\ASP

  - by coure06

  I have created a webservice which is saving some data into to db. But i am getting this error Cannot open database "test" requested by the login. The login failed. Login failed for user 'xyz\ASPNET'.

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• Can't find which row is causing conversion error

  - by Marwan

  I have the following table: CREATE TABLE [dbo].[Accounts1]( [AccountId] [nvarchar](50) NULL, [ExpiryDate] [nvarchar](50) NULL ) I am trying to convert nvarchar to datetime using this query: select convert(datetime, expirydate) from accounts I get this error: Conversion failed when converting datetime from character string. The status bar says "2390 rows". I go to rows 2390, 2391 and 2392. There is nothing wrong with the data there. I even try to convert those particular rows and it works. How can I find out which row(s) is causing the conversion error?

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• C# SqlDataAdapter not populating DataSet

  - by Wesley

  I have searched the net and searched the net only to not quite find the probably I am running into. I am currently having an issue getting a SqlDataAdapter to populate a DataSet. I am running Visual Studio 2008 and the query is being sent to a local instance of SqlServer 2008. If I run the query itself in SqlServer, I do get information. Code is as follows: string theQuery = "select Password from Employees where employee_ID = '@EmplID'"; SqlDataAdapter theDataAdapter = new SqlDataAdapter(); theDataAdapter.SelectCommand = new SqlCommand(theQuery, conn); theDataAdapter.SelectCommand.Parameters.Add("@EmplID", SqlDbType.VarChar).Value = "EmployeeName"; theDataAdapter.Fill(theSet); The code to read the dataset: foreach (DataRow theRow in theSet.Tables[0].Rows) { //process row info } If there is any more info I can supply please let me know.

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• Modeling Tools that understand both Relational and LDAP

  - by jm04469

  I am looking to do some modeling and would like to have a tool that can capture not only a relational model like ERWIN but also allow us to easily port to LDAP as an option. NOTE: Visio can connect to an existing LDAP server and draw, but does not allow for you to model first and then deploy, unlike its relational capabilities.

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• Stored Procedure in Entity Framework

  - by kamal

  Hi I had added the Stored procedure in my Entity framework and i also imported the functions in the edmx. Is it must to add all the three functions insert, update, and delete functions to a table. I had tried with insert alone and also with all, but why can't i get the name of the stored procedure in the connection string. Let me know what i done clearly. I had added the sp i had imported the functions in the model browser. i had also mapped the insert, update and delete function to the table with return type only for insert and update. Still i can't get the name of SP in the connection string. Please let me know how could i resolve this issue. Thanks in Advance, Kamal.

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• Can this be done with the ORM? - Django

  - by RadiantHex

  Hi folks, I have a few item listed in a database, ordered through Reddit's algorithm. This is it: def reddit_ranking(post): t = time.mktime(post.created_on.timetuple()) - 1134000000 x = post.score if x>0: y=1 elif x==0: y=-0 else: y=-1 if x<0: z=1 else: z=x return (log(z) + y * t/45000) I'm wondering if there is any clever way of using Django's ORM, in order to UPDATE the models in bulk. Without doing this: items = Item.objects.filter(created_on__gte=datetime.now()-timedelta(days=7)) for item in items: item.reddit_rank = reddit_rank(item) item.save() I know about the F() object, but I can't figure out if this function can be performed inside the ORM. Any ideas? Help would be very much appreciated!

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• PostgreSQL - fetch the row which has the Max value for a column

  - by Joshua Berry

  I'm dealing with a Postgres table (called "lives") that contains records with columns for time_stamp, usr_id, transaction_id, and lives_remaining. I need a query that will give me the most recent lives_remaining total for each usr_id There are multiple users (distinct usr_id's) time_stamp is not a unique identifier: sometimes user events (one by row in the table) will occur with the same time_stamp. trans_id is unique only for very small time ranges: over time it repeats remaining_lives (for a given user) can both increase and decrease over time example: time_stamp|lives_remaining|usr_id|trans_id ----------------------------------------- 07:00 | 1 | 1 | 1 09:00 | 4 | 2 | 2 10:00 | 2 | 3 | 3 10:00 | 1 | 2 | 4 11:00 | 4 | 1 | 5 11:00 | 3 | 1 | 6 13:00 | 3 | 3 | 1 As I will need to access other columns of the row with the latest data for each given usr_id, I need a query that gives a result like this: time_stamp|lives_remaining|usr_id|trans_id ----------------------------------------- 11:00 | 3 | 1 | 6 10:00 | 1 | 2 | 4 13:00 | 3 | 3 | 1 As mentioned, each usr_id can gain or lose lives, and sometimes these timestamped events occur so close together that they have the same timestamp! Therefore this query won't work: SELECT b.time_stamp,b.lives_remaining,b.usr_id,b.trans_id FROM (SELECT usr_id, max(time_stamp) AS max_timestamp FROM lives GROUP BY usr_id ORDER BY usr_id) a JOIN lives b ON a.max_timestamp = b.time_stamp Instead, I need to use both time_stamp (first) and trans_id (second) to identify the correct row. I also then need to pass that information from the subquery to the main query that will provide the data for the other columns of the appropriate rows. This is the hacked up query that I've gotten to work: SELECT b.time_stamp,b.lives_remaining,b.usr_id,b.trans_id FROM (SELECT usr_id, max(time_stamp || '*' || trans_id) AS max_timestamp_transid FROM lives GROUP BY usr_id ORDER BY usr_id) a JOIN lives b ON a.max_timestamp_transid = b.time_stamp || '*' || b.trans_id ORDER BY b.usr_id Okay, so this works, but I don't like it. It requires a query within a query, a self join, and it seems to me that it could be much simpler by grabbing the row that MAX found to have the largest timestamp and trans_id. The table "lives" has tens of millions of rows to parse, so I'd like this query to be as fast and efficient as possible. I'm new to RDBM and Postgres in particular, so I know that I need to make effective use of the proper indexes. I'm a bit lost on how to optimize. I found a similar discussion here. Can I perform some type of Postgres equivalent to an Oracle analytic function? Any advice on accessing related column information used by an aggregate function (like MAX), creating indexes, and creating better queries would be much appreciated! P.S. You can use the following to create my example case: create TABLE lives (time_stamp timestamp, lives_remaining integer, usr_id integer, trans_id integer); insert into lives values ('2000-01-01 07:00', 1, 1, 1); insert into lives values ('2000-01-01 09:00', 4, 2, 2); insert into lives values ('2000-01-01 10:00', 2, 3, 3); insert into lives values ('2000-01-01 10:00', 1, 2, 4); insert into lives values ('2000-01-01 11:00', 4, 1, 5); insert into lives values ('2000-01-01 11:00', 3, 1, 6); insert into lives values ('2000-01-01 13:00', 3, 3, 1);

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• like operator issue

  - by Domnic

  I have dom table select * from dom dom table details: id name skills 1 dom c,c++ here i want to retrive query using like operator select * from dom where skills like '%c,c++%' then i got the desired result.....thats not a problem suppose if i want to use the belove query select * from dom where skills like '%C++,C%' i didnt get result So i have to show details even if i search reverse order in database how can i?

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