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• Filter on count(*) in oracle

  - by chris

  I have a grouped query, and would like to filter it based on count(*) Can I do this without a subquery? This is what I have currently: select * from (select ID, count(*) cnt from name group by ID) where cnt > 1;

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• create temporary table from cursor

  - by Claudiu

  Is there any way, in PostgreSQL accessed from Python using SQLObject, to create a temporary table from the results of a cursor? Previously, I had a query, and I created the temporary table directly from the query. I then had many other queries interacting w/ that temporary table. Now I have much more data, so I want to only process 1000 rows at a time or so. However, I can't do CREATE TEMP TABLE ... AS ... from a cursor, not as far as I can see. Is the only thing to do something like: rows = cur.fetchmany(1000); cur2 = conn.cursor() cur2.execute("""CREATE TEMP TABLE foobar (id INTEGER)""") for row in rows: cur2.execute("""INSERT INTO foobar (%d)""" % row) or is there a better way? This seems awfully inefficient.

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• How to get common field in ten tables with different field name

  - by Fero

  Hi all, I am having a common field in ten tables with different field name. example: table1: t1_id     t1_location 1         india 2         china 3         america table2: t2_id     t2_location 4         london 5         australia 6         america Now my o/p should be: location india china america london australia How should i get that using mysql query. thanks in advance

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• ColdFusion Timeout Error

  - by Jason

  I have a scheduled task that runs once a day that builds an XML file that I pass off to another group. Recently the amount of data has greatly increased and is now causing the task to time out (I think). I have tried to optimize my script as much as possible but with no luck. It times out long before an hour and I don't get any kind of ColdFusion error. Instead I get a "This page cannot be found" after it runs. Could this be a timeout someplace other than Coldfusion? Is there a more efficient way to build this XML file? select PersonID, FirstName, LastName from People select d.DepartmentID, DepartmentName, pd.PersonID from Department d inner join PersonDepartment pd on d.DepartmentID = pd.DepartmentID select PaperID, PaperTitle, PaperDescription, pp.PersonID from Paper p inner join PersonPaper pp on p.PaperID = pp.PaperID select DepartmentID, DepartmentName from getDepartments where PersonID = #getPeople.PersonID# select PaperID, PaperDescription from getpapers where PersonID = #getPeople.PersonID# #getPeople.PersonID# #getPeople.Firstname# #getPeople.LastName# #getPersonDepartments.DepartmentID# #getPersonDepartments.DepartmentName# #getPersonPapers.PaperID# #getPersonPapers.PaperDescription# Done!

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• Foreach loop problem for Iqueyable object

  - by Vikas

  Hi, Can we use foreach loop for Iqueryable object? I'd like to do something as follow: query = Iqueryable<Myclass> = objDataContext.Myclass; // objDataContext is an object of LINQ datacontext class int[] arr1 = new int[] { 3, 4, 5 }; foreach (int i in arr1) { query = query.Where(q => (q.f_id1 == i || q.f_id2 == i || q.f_id3 == i)); } It gives me wrong output as each time value if i is changed.

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• Create a trigger on Oracle Databae that updates the field in a table when a field in onether table i

  - by GigaPr

  Hi, i have two tables Order(id, date, note) and Delivery(Id, Note, Date) I want to create a trigger that updates the date in delivery when the date is updated in Order I was thinking to do something like CREATE OR REPLACE TRIGGER your_trigger_name BEFORE UPDATE ON Order DECLARE BEGIN UPDATE Delivery set date = ??? where id = ??? END; How do i get the date and row id? thanks

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• How to save to two tables using one SQLAlchemy model

  - by Oatman

  I have an SQLAlchemy ORM class, linked to MySQL, which works great at saving the data I need down to the underlying table. However, I would like to also save the identical data to a second archive table. Here's some psudocode to try and explain what I mean my_data = Data() #An ORM Class my_data.name = "foo" #This saves just to the 'data' table session.add(my_data) #This will save it to the identical 'backup_data' table my_data_archive = my_data my_data_archive.__tablename__ = 'backup_data' session.add(my_data_archive) #And commits them both session.commit() Just a heads up, I am not interested in mapping a class to a JOIN, as in: http://www.sqlalchemy.org/docs/05/mappers.html#mapping-a-class-against-multiple-tables

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• Oracle : select maximum value from different comulms of the same row

  - by gregseth

  The whole question is pretty much in the title. For each row of the table I'd like to select the maximum of a subset of columns. For example, from this table name m1 m2 m3 m4 A 1 2 3 4 B 6 3 4 5 C 1 5 2 1 the result would be name max A 4 B 6 C 5 The query must be compatible oracle 8i. Thanks.

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• Restricting deletion with NHibernate

  - by FrontSvin

  I'm using NHibernate (fluent) to access an old third-party database with a bunch of tables, that are not related in any explicit way. That is a child tables does have parentID columns which contains the primary key of the parent table, but there are no foreign key relations ensuring these relations. Ideally I would like to add some foreign keys, but cannot touch the database schema. My application works fine, but I would really like impose a referential integrity rule that would prohibit deletion of parent objects if they have children, e.i. something similar 'ON DELETE RESTRICT' but maintained by NHibernate. Any ideas on how to approach this would be appreciated. Should I look into the OnDelete() method on the IInterceptor interface, or are there other ways to solve this? Of course any solution will come with a performance penalty, but I can live with that.

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• help with delete where not in query

  - by kralco626

  I have a lookup table (##lookup). I know it's bad design because I'm duplicating data, but it speeds up my queries tremendously. I have a query that populates this table insert into ##lookup select distinct col1,col2,... from table1...join...etc... I would like to simulate this behavior: delete from ##lookup insert into ##lookup select distinct col1,col2,... from table1...join...etc... This would clearly update the table correctly. But this is a lot of inserting and deleting. It messes with my indexes and locks up the table for selecting from. This table could also be updated by something like: delete from ##lookup where not in (select distinct col1,col2,... from table1...join...etc...) insert into ##lookup (select distinct col1,col2,... from table1...join...etc...) except if it is already in the table The second way may take longer, but I can say "with no lock" and I will be able to select from the table. Any ideas on how to write the query the second way?

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• Embedded Java Databases for Large Data Sets

  - by ExAmerican

  I would like to port a PHP/MySQL-based client/server application to be a standalone desktop application written in Java. The database has grown to be fairly large, with several tables with hundreds of thousands of rows. I expect these could grow to over a million entries for certain tables. What embedded database would best handle this? HSQLDB and Sqlite seem to be the obvious choices, though I'm guessing there are others out there as well. My main priorities are the ability to perform queries on large amounts of data efficiently (this thread seems to confirm Sqlite can handle this) and the ease with which I can import old data from MySQL (I remember HSQLDB being kind of a pain for that). Note: I am aware that similar questions comparing embedded databases have been posted before (for example here and here) but as my priorities differ somewhat from most applications considering the large data migration I thought it justified a new question.

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• Finding the count of characters and numbers in a string

  - by Aspirant

  Hi I have a table test as below NAME --------- abc1234 XYZ12789 a12X8b78Y9c5Z I try to find out the count of number of numbers and characters in the string as select name,length(replace(translate(lower(name),'abcdefghijklmnopqrstuvwxyz',' '),' ','')) as char_count, length(replace(translate(name,'1234567890',' '),' ','')) as num_count from test6; Its executing fine giving the output NAME CHAR_COUNT NUM_COUNT abc1234 4 3 XYZ12789 5 3 a12X8b78Y9c5Z 7 6 But my question is there any option by not giving the abcdefghijklmnopqrstuvwxyz and 1234567890 manually

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• Selecting rows with references across tables in SQLite 3

  - by ChristianK

  Hey there, I have a problem with a SQLite photo/album database. The database contains 3 tables: Albums id name hide -------------------------- 1 Holiday 2010 1 2 Day Trip 0 Photos id file ----------------- 1 photo1.jpg 2 photo2.jpg 3 photo3.jpg 4 photo4.jpg Relation (connects photos with albums) album photo ----------------- 1 1 1 2 2 3 2 1 A photo can be assigned to zero, one or several albums. Each album has a column 'hide' that indicates, whether the photos of this album should be ignored. I'm trying to find a SELECT query that returns all photos that are not assigned to an album + all the photos that are in albums which are not hidden (i.e. that have their 'hide' value set to 0). I came up with a query that selects photos in visible albums, but I don't know how to include the photos that are not assigned to an album. SELECT file FROM photos, albums, relation WHERE photos.id = relation.photo AND albums.id = relation.album AND albums.hide = 0 This query returns photo3.jpg and the required result would be photo3.jpg photo4.jpg because photo4.jpg is not assigned to album in the Relation table. Do you know how to solve this? Thank you very much for your help!

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• The best practice to setup hierarchy data

  - by eski

  I'm trying to figure out the best practice to setup hierarchy data that i take from a database into some contoller that would show the hierachy. Basicly this would look like a normal tree but when you press the items that are under "chapters" you get a link to another page. I have these tables and this is the way they are connected Period Courses Subjects Chapters I select Period from a DropDownBox and then i want all the courses in that period to line up. Under each course would be the subject and under them are the chapers, typical hierarchy. The tables are linked together with refrences to each other in linear way. I have tried to use treeview to show this, but dont understand how to do it. I though i could use <ul><il> tags and do it at runtime. Reapeter or datalist, possible ? Is it better to do this with databinding in XAML or in code ?

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• asp.net mvc checkbox hierarchy

  - by mazhar

  I want to create a checkboxes hierarchy like this in mvc2.How would I be able to achieve this in the most simplest manner. Administrator Manage User Add Edit Delete View Manage Feature Add Edit Delete View Moderator Manage User Add Edit Delete View Manage Feature Add Edit Delete View

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• When running UPDATE ... datetime = NOW(); will all rows updated have the same date/time?

  - by Darryl Hein

  When you run something similar to: UPDATE table SET datetime = NOW(); on a table with 1 000 000 000 records and the query takes 10 seconds to run, will all the rows have the exact same time (minutes and seconds) or will they have different times? In other words, will the time be when the query started or when each row is updated? I'm running MySQL, but I'm thinking this applies to all dbs.

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• Which index is used in select and why?

  - by Lukasz Lysik

  I have the table with zip codes with following columns: id - PRIMARY KEY code - NONCLUSTERED INDEX city When I execute query SELECT TOP 10 * FROM ZIPCodes I get the results sorted by id column. But when I change the query to: SELECT TOP 10 id FROM ZIPCodes I get the results sorted by code column. Again, when I change the query to: SELECT TOP 10 code FROM ZIPCodes I get the results sorted by code column again. And finally when I change to: SELECT TOP 10 id,code FROM ZIPCodes I get the results sorted by id column. My question is in the title of the question. I know which indexes are used in the queries, but my question is, why those indexes are used? I the second query (SELECT TOP 10 id FROM ZIPCodes) wouldn't it be faster if the clusteder index was used? How the query engine chooses which index to use?

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• How do I delete orphan entities using hibernate and JPA on a many-to-many relationship?

  - by user368453

  I want to delete orphan entities using hibernate and JPA on a many-to-many relationship but all that I found was this atibute the attribute. org.hibernate.annotations.CascadeType.DELETE_ORPHAN ( i.e. @Cascade(value={org.hibernate.annotations.CascadeType.DELETE_ORPHAN) ), which works only for one-to-many relationships. I want to know if I can delete the orphan ones on my many-to-many relationship. I´d be happy if anyone could help me... Thanks in advance !

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• What is the most "database independent" way of creating a variable length text field in a database

  - by Thibaut Colar

  I want to create a text field in the database, with no specific size (it will store text of length unknown in some case) - the particular text are serialized simple object (~ JSON) What is the most database independent way to do this : - a varchar with no size specified (don't think all db support this) - a 'text' field, this seems to be common, but I don't believe it's a standard - a blob or other object of that kind ? - a varchar of a a very large size (that's inefficient and wastes disk space probably) - Other ? I'm using JDBC, but I'd like to use something that is supported in most DB (oracle, mysql, postgresql, derby, HSQL, H2 etc...) Thanks.

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• Database select * for a Noob

  - by Kevin Brown

  I've heard that it's bad to select all the fields in a database. Is this true, and if so, why?

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• ora-30926 error

  - by user1331181

  I am trying to execute the following merge statement but is is showing me ora-30926 error merge into test_output target_table USING (SELECT c.test_code, c.v_report_id, upper_score, CASE WHEN c.test_code = 1 THEN b.mean_diff WHEN c.test_code = 2 THEN b.norm_dist WHEN c.test_code = 3 THEN b.ks_stats WHEN c.test_code = 4 THEN b.ginni WHEN c.test_code = 5 THEN b.auroc WHEN c.test_code = 6 THEN b.info_stats WHEN c.test_code = 7 THEN b.kl_stats END val1 FROM combined_approach b inner join test_output c on b.v_report_id = c.v_report_id and c.upper_score = b.band_code WHERE c.v_report_id = lv_report_id ORDER BY c.test_code) source_table on(target_table.v_report_id = source_table.v_report_id and target_table.v_report_id = lv_report_id) when matched then update SET target_table.upper_value = source_table.val1;

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• how to copy from one column to another but with different format

  - by Bob

  I hv a table like this:- Item Model Remarks ----------------------------------------- A 10022009 B 10032006 C 05081997 I need to copy the info from "Model" to "Remarks" with the following format:- Item Model Remarks ----------------------------------------- A 10022009 20090210 B 10032006 20060310 C 05081997 19970805 Thanks

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• Query for multiple joins

  - by Shailaja

  i have 3 tables named dataset,dataelem and transformdataelem with column names as below: main.Dataset ------------ datasetID (PK) applicationID main.Dataelem ------------- dataelemID(PK) datasetID(FK) dataelemname biztermID main.Transformdataelem ---------------------- OutputdataelemID InputdataelemID My requirement is: All tables are referenced. Extract all the dataelemId rows from dataelem table where applicationID of dataset table is equal to 1044 and biztermid shud be null. Then whatever resultant dataelemIDs from the above query should be matched with outputdataelemID of Transformdataelem table and we shud get the respective input dataelemId's. Again with these matched inputdataelemID's we shud get the dataelemname's from datelem table.

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• LINQ2SQL:Calling Stored procedure and reading return value

  - by Shyju

  Using LINQ 2SQL , How can i call a stored procedure which returns either 1 or 0 when being executed.My procedure has 3 input params.I want to know the return value from procedure in my code too.

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• user_objects oracle

  - by mysticfalls

  I would just like to ask what is the difference between user_constraints and user_objects. I have this two database. I run a script on both DB that resulted a unique constraint error. To solve the problem I delete the constraint on user_constraint table for both DB. After that DB1 run without error.. DB2 however failed, I checked the user_constraint for both db and the constraints was deleted. I was asked to check the user_objects.. and found that DB2 has that same constraint_name as the object_name in user_objects table.. Any info regarding their relationship, use, similarites, etc will be appreciated ... Thanks..

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