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  • Stop invalid data in a attribute with foreign key constraint using triggers?

    - by Eternal Learner
    How to specify a trigger which checks if the data inserted into a tables foreign key attribute, actually exists in the references table. If it exist no action should be performed , else the trigger should delete the inserted tuple. Eg: Consider have 2 tables R(A int Primary Key) and S(B int Primary Key , A int Foreign Key References R(A) ) . I have written a trigger like this : Create Trigger DelS BEFORE INSERT ON S FOR EACH ROW BEGIN Delete FROM S where New.A <> ( Select * from R;) ); End; I am sure I am making a mistake while specifying the inner sub query within the Begin and end Blocks of the trigger. My question is how do I make such a trigger ?

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  • Which of these queries is preferable?

    - by bread
    I've written the same query as a subquery and a self-join. Is there any obvious argument for one over the other here? SUBQUERY: SELECT prod_id, prod_name FROM products WHERE vend_id = (SELECT vend_id FROM products WHERE prod_id = ‘DTNTR’); SELF-JOIN: SELECT p1.prod_id, p1.prod_name FROM products p1, products p2 WHERE p1.vend_id = p2.vend_id AND p2.prod_id = ‘DTNTR’;

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  • Service Broker not working after database restore

    - by roryok
    Have a working Service Broker set up on a server, we're in the process of moving to a new server but I can't seem to get Service Broker set up on the new box. Have done the obvious (to me) things like Enabling Broker on the DB, dropping the route, services, contract, queues and even message type and re adding them, setting ALTER QUEUE with STATUS ON SELECT * FROM sys.service_queues gives me a list of the queues, including my own two, which show as activation_enabled, receive_enabled etc. Needless to say the queues aren't working. When I drop messages into them nothing goes in and nothing comes out. Any ideas? I'm sure there's something really obvious I've missed...

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  • explain these select statements!

    - by user329820
    Hi, I can not get the difference betwwn these statements? would you please help me,I have read some sample of select statements but I did not get these ones. SELECT 'B' FROM T WHERE A = (SELECT NULL); SELECT 'C' FROM T WHERE A = ANY (SELECT NULL); SELECT 'D' FROM T WHERE A = A; I use MySQL

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  • Removal of table primary key in MySQL

    - by marionmaiden
    Hello, I've removed the primary key of one table of my MySQL database, but now, when I use the MySQL Administrator and try to edit some data of this table, it doesn't allow me to do this. The button edit that appears in the bottom of the table keeps visible, but disabled to click.

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  • jpa join query on a subclass

    - by Brian
    I have the following relationships in JPA (hibernate). Object X has two subclasses, Y and Z. Object A has a manyToOne relationship to object X. (Note, this is a one-sided relationship so object X cannot see object A). Now, I want to get the max value of a column in object A, but only where the relationship is of a specific subtype, ie...Y. So, that equates to...get the max value of column1 in object A, across all instances of A where they have a relationship with Y. Is this possible? I'm a bit lost as how to query it. I was thinking of something like: String query = "SELECT MAX(a.columnName) FROM A a join a.x; Query query = super.entityManager.createQuery(query); query.execute(); However that doesn't take account of the subclass of X...so I'm a bit lost. Any help would be much appreciated.

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  • trouble connecting to MySql DB (PHP)

    - by user332817
    Hi I have the following PHP code to connect to my db. <?php ob_start(); $host="localhost"; // Host name $username="root"; // Mysql username $password=""; // Mysql password $db_name="test"; // Database name $tbl_name="members"; // Table name // Connect to server and select databse. mysql_connect("$host", "$username", "$password")or die("cannot connect"); ?> however I get the following error: Warning: mysql_connect() [function.mysql-connect]: [2002] A connection attempt failed because the connected party did not (trying to connect via tcp://localhost:3306) in C:\Program Files (x86)\EasyPHP-5.3.2i\www\checklogin.php on line 11 Warning: mysql_connect() [function.mysql-connect]: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond. in C:\Program Files (x86)\EasyPHP-5.3.2i\www\checklogin.php on line 11 Fatal error: Maximum execution time of 30 seconds exceeded in C:\Program Files (x86)\EasyPHP-5.3.2i\www\checklogin.php on line 11 I am able to add a db/tables via phpmyadmin but I cant connect using php. here is a screenshot of my phpmyadmin page: http://img294.imageshack.us/img294/1589/sqls.jpg any help would be appreciated, thanks in advance.

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  • what's the performance difference between int and varchar for primary keys

    - by user568576
    I need to create a primary key scheme for a system that will need peer to peer replication. So I'm planning to combine a unique system ID and a sequential number in some way to come up with unique ID's. I want to make sure I'll never run out of ID's, so I'm thinking about using a varchar field, since I could always add another character if I start running out. But I've read that integers are better optimized for this. So I have some questions... 1) Are integers really better optimized? And if they are, how much of a performance difference is there between varchars and integers? I'm going to use firebird for now. But I may switch later. Or possibly support multiple db's. So I'm looking for generalizations, if that's possible. 2) If integers are significantly better optimized, why is that? And is it likely that varchars will catch up in the future, so eventually it won't matter anyway? My varchar keys won't have any meaning, except for the unique system ID part. But I may want to obscure that somehow. Also, I plan to efficiently use all the bits of each character. I don't, for example, plan to code the integer 123 as the character string "123". So I don't think varchars will require more space than integers.

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  • Stored Procedure: Reducing Table Data

    - by SumGuy
    Hi Guys, A simple question about Stored Procedures. I have one stored procedure collecting a whole bunch of data in a table. I then call this procedure from within another stored procedure. I can copy the data into a new table created in the calling procedure but as far as I can see the tables have to be identical. Is this right? Or is there a way to insert only the data I want? For example.... I have one procedure which returns this: SELECT @batch as Batch, @Count as Qty, pd.Location, cast(pd.GL as decimal(10,3)) as [Length], cast(pd.GW as decimal(10,3)) as Width, cast(pd.GT as decimal(10,3)) as Thickness FROM propertydata pd GROUP BY pd.Location, pd.GL, pd.GW, pd.GT I then call this procedure but only want the following data: DECLARE @BatchTable TABLE ( Batch varchar(50), [Length] decimal(10,3), Width decimal(10,3), Thickness decimal(10,3), ) INSERT @BatchTable (Batch, [Length], Width, Thickness) EXEC dbo.batch_drawings_NEW @batch So in the second command I don't want the Qty and Location values. However the code above keeps returning the error: "Insert Error: Column name or number of supplied values does not match table"

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  • Filling a LOV in Oracle Apex based on data in another text box

    - by Martin Pugh
    I am fairly new to Oracle Apex, and have a problem. Our application currently has a method of entering data, with several text boxes and Optional List of Values. I would like to have an LOV based on information in another text box like so: select APPOINTMENT_ID PATIENT_ID from APPOINTMENT where PATIENT_ID = :P9_PAT_NUM where P9_PAT_NUM is a patient number in a text box. However, this would apparently only work if the text box has already been submitted, else it assumes the text box is null. Is there any way to get this working with an LOV, or perhaps some other method?

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  • Getting counts of 0 from a query with a double group by

    - by Maltiriel
    I'm trying to write a query that gets the counts for a table (call it item) categorized by two different things, call them type and code. What I'm hoping for as output is the following: Type Code Count 1 A 3 1 B 0 1 C 10 2 A 0 2 B 13 2 C 2 And so forth. Both type and code are found in lookup tables, and each item can have just one type but more than one code, so there's also a pivot (aka junction or join) table for the codes. I have a query that can get this result: Type Code Count 1 A 3 1 C 10 2 B 13 2 C 2 and it looks like (with join conditions omitted): SELECT typelookup.name, codelookup.name, COUNT(item.id) FROM typelookup LEFT OUTER JOIN item JOIN itemcodepivot RIGHT OUTER JOIN codelookup GROUP BY typelookup.name, codelookup.name Is there any way to alter this query to get the results I'm looking for? This is in MySQL, if that matters. I'm not actually sure this is possible all in one query, but if it is I'd really like to know how. Thanks for any ideas.

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  • Why is SQLite3 using covering indices instead of the indices I created?

    - by Geoff
    I have an extremely large database (contacts has ~3 billion entries, people has ~280 million entries, and the other tables have a negligible number of entries). Most other queries I've run are really fast. However, I've encountered a more complicated query that's really slow. I'm wondering if there's any way to speed this up. First of all, here is my schema: CREATE TABLE activities (id INTEGER PRIMARY KEY, name TEXT NOT NULL); CREATE TABLE contacts ( id INTEGER PRIMARY KEY, person1_id INTEGER NOT NULL, person2_id INTEGER NOT NULL, duration REAL NOT NULL, -- hours activity_id INTEGER NOT NULL -- FOREIGN_KEY(person1_id) REFERENCES people(id), -- FOREIGN_KEY(person2_id) REFERENCES people(id) ); CREATE TABLE people ( id INTEGER PRIMARY KEY, state_id INTEGER NOT NULL, county_id INTEGER NOT NULL, age INTEGER NOT NULL, gender TEXT NOT NULL, -- M or F income INTEGER NOT NULL -- FOREIGN_KEY(state_id) REFERENCES states(id) ); CREATE TABLE states ( id INTEGER PRIMARY KEY, name TEXT NOT NULL, abbreviation TEXT NOT NULL ); CREATE INDEX activities_name_index on activities(name); CREATE INDEX contacts_activity_id_index on contacts(activity_id); CREATE INDEX contacts_duration_index on contacts(duration); CREATE INDEX contacts_person1_id_index on contacts(person1_id); CREATE INDEX contacts_person2_id_index on contacts(person2_id); CREATE INDEX people_age_index on people(age); CREATE INDEX people_county_id_index on people(county_id); CREATE INDEX people_gender_index on people(gender); CREATE INDEX people_income_index on people(income); CREATE INDEX people_state_id_index on people(state_id); CREATE INDEX states_abbreviation_index on states(abbreviation); CREATE INDEX states_name_index on states(name); Note that I've created an index on every column in the database. I don't care about the size of the database; speed is all I care about. Here's an example of a query that, as expected, runs almost instantly: SELECT count(*) FROM people, states WHERE people.state_id=states.id and states.abbreviation='IA'; Here's the troublesome query: SELECT * FROM contacts WHERE rowid IN (SELECT contacts.rowid FROM contacts, people, states WHERE contacts.person1_id=people.id AND people.state_id=states.id AND states.name='Kansas' INTERSECT SELECT contacts.rowid FROM contacts, people, states WHERE contacts.person2_id=people.id AND people.state_id=states.id AND states.name='Missouri'); Now, what I think would happen is that each subquery would use each relevant index I've created to speed this up. However, when I show the query plan, I see this: sqlite> EXPLAIN QUERY PLAN SELECT * FROM contacts WHERE rowid IN (SELECT contacts.rowid FROM contacts, people, states WHERE contacts.person1_id=people.id AND people.state_id=states.id AND states.name='Kansas' INTERSECT SELECT contacts.rowid FROM contacts, people, states WHERE contacts.person2_id=people.id AND people.state_id=states.id AND states.name='Missouri'); 0|0|0|SEARCH TABLE contacts USING INTEGER PRIMARY KEY (rowid=?) (~25 rows) 0|0|0|EXECUTE LIST SUBQUERY 1 2|0|2|SEARCH TABLE states USING COVERING INDEX states_name_index (name=?) (~1 rows) 2|1|1|SEARCH TABLE people USING COVERING INDEX people_state_id_index (state_id=?) (~5569556 rows) 2|2|0|SEARCH TABLE contacts USING COVERING INDEX contacts_person1_id_index (person1_id=?) (~12 rows) 3|0|2|SEARCH TABLE states USING COVERING INDEX states_name_index (name=?) (~1 rows) 3|1|1|SEARCH TABLE people USING COVERING INDEX people_state_id_index (state_id=?) (~5569556 rows) 3|2|0|SEARCH TABLE contacts USING COVERING INDEX contacts_person2_id_index (person2_id=?) (~12 rows) 1|0|0|COMPOUND SUBQUERIES 2 AND 3 USING TEMP B-TREE (INTERSECT) In fact, if I show the query plan for the first query I posted, I get this: sqlite> EXPLAIN QUERY PLAN SELECT count(*) FROM people, states WHERE people.state_id=states.id and states.abbreviation='IA'; 0|0|1|SEARCH TABLE states USING COVERING INDEX states_abbreviation_index (abbreviation=?) (~1 rows) 0|1|0|SEARCH TABLE people USING COVERING INDEX people_state_id_index (state_id=?) (~5569556 rows) Why is SQLite using covering indices instead of the indices I created? Shouldn't the search in the people table be able to happen in log(n) time given state_id which in turn is found in log(n) time?

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  • Database Design Question: GUID + Natural Numbers

    - by Alan
    For a database I'm building, I've decided to use natural numbers as the primary key. I'm aware of the advantages that GUID's allow, but looking at the data, the bulk of row's data were GUID keys. I want to generate XML records from the database data, and one problem with natural numbers is that I don't want to expose my database key's to the outside world, and allow users to guess "keys." I believe GUID's solve this problem. So, I think the solution is to generate a sparse, unique iD derived from the natural ID (hopefully it would be 2-way), or just add an extra column in the database and store a guid (or some other multibyte id) The derived value is nicer because there is no storage penalty, but it would be easier to reverse and guess compared to a GUID. I'm (buy) curious as to what others on SO have done, and what insights they have.

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  • Does Table.InsertOnSubmit create a copy of the original table?

    - by Bryan
    Using InsertOnSubmit seems to have some memory overhead. I have a System.Data.Linq.Table<User> table. When I do table.InsertOnSubmit(user) and then int count = table.Count(), the memory usage of my application increases by roughly the size of the User table, but the count is the number of items before user was inserted. So I'm guess an enumeration after InsertOnSubmit will create a copy of the table. Is that true?

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  • how to combine the related version in group by

    - by randeepsp
    select count(a),b,c from APPLE join MANGO on (APPLE.link=MANGO.link) join ORANGE on (APPLE.link=ORANGE.link) where id='camel' group by b,c; the column b gives values like 1.0 1.0,R 1.0,B 2.0 2.0,B 2.0,R 3.0,C 3.0,R is there a way to modify the above quer so that all 1.0 and 1.0,R and 1.0,B are merged as 1.0 and 2.0,2.0,B are merged as 2.0 and same way for 3.0 and 4.0

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  • advanced select in Stored Procedure

    - by Auro
    Hey i got this Table: CREATE TABLE Test_Table ( old_val VARCHAR2(3), new_val VARCHAR2(3), Updflag NUMBER, WorkNo NUMBER ); and this is in my Table: INSERT INTO Test_Table (old_val, new_val, Updflag , WorkNo) VALUES('1',' 20',0,0); INSERT INTO Test_Table (old_val, new_val, Updflag , WorkNo) VALUES('2',' 20',0,0); INSERT INTO Test_Table (old_val, new_val, Updflag , WorkNo) VALUES('2',' 30',0,0); INSERT INTO Test_Table (old_val, new_val, Updflag , WorkNo) VALUES('3',' 30',0,0); INSERT INTO Test_Table (old_val, new_val, Updflag , WorkNo) VALUES('4',' 40',0,0); INSERT INTO Test_Table (old_val, new_val, Updflag , WorkNo) VALUES('4',' 40',0,0); now my Table Looks like this: Row Old_val New_val Updflag WorkNo 1 '1' ' 20' 0 0 2 '2' ' 20' 0 0 3 '2' ' 30' 0 0 4 '3' ' 30' 0 0 5 '4' ' 40' 0 0 6 '5' ' 40' 0 0 (if the value in the new_val column are same then they are together and the same goes to old_val) so in the example above row 1-4 are together and row 5-6 at the moment i have in my Stored Procedure a cursor: SELECT t1.Old_val, t1.New_val, t1.updflag, t1.WorkNo FROM Test_Table t1 WHERE t1.New_val = ( SELECT t2.New_val FROM Test_Table t2 WHERE t2.Updflag = 0 AND t2.Worknr = 0 AND ROWNUM = 1 ) the output is this: Row Old_val New_val Updflag WorkNo 1 1 20 0 0 2 2 20 0 0 my Problem is, i dont know how to get row 1 to 4 with one select. (i had an idea with 4 sub-querys but this wont work if its more data that matches together) does anyone of you have an idea?

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  • sqlite3.OperationalError: database is locked - non-threaded application

    - by James C
    Hi, I have a Python application which throws the standard sqlite3.OperationalError: database is locked error. I have looked around the internet and could not find any solution which worked (please note that there is no multiprocesses/threading going on, and as you can see I have tried raising the timeout parameter). The sqlite file is stored on the local hard drive. The following function is one of many which accesses the sqlite database, and runs fine the first time it is called, but throws the above error the second time it is called (it is called as part of a for loop in another function): def update_index(filepath): path = get_setting('Local', 'web') stat = os.stat(filepath) modified = stat.st_mtime index_file = get_setting('Local', 'index') connection = sqlite3.connect(index_file, 30) cursor = connection.cursor() head, tail = os.path.split(filepath) cursor.execute('UPDATE hwlive SET date=? WHERE path=? AND name=?;', (modified, head, tail)) connection.commit() connection.close() Many thanks.

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  • Indexed key vs indexed separate columns, which one is faster ?

    - by Jerry
    In MYSQL, from a pure performance perspective, if I have a table with large amount of data with 10/1 read/write ratio. is it faster in read/write performance to have 4 search criteria in separate columns and all indexed or have them combined in to one single string acting as a key and store in one indexed column ? e.g. say this table with 5 columns, first name, last name, sex, country and file where the first four columns will ALWAYS be given as a part of search parameters in a search or have a table with two columns, key and file. where the value of key can be john-smith-male-australia ?? I don't quite get the pros and cons. the point I try to stress is the fact that all parameters will be given.in a search.

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  • Run SSIS Package from T-SQL

    - by Dr. Zim
    I noticed you can use the following stored procedures (in order) to schedule a SSIS package: msdb.dbo.sp_add_category @class=N'JOB', @type=N'LOCAL', @name=N'[Uncategorized (Local)]' msdb.dbo.sp_add_job ... msdb.dbo.sp_add_jobstep ... msdb.dbo.sp_update_job ... msdb.dbo.sp_add_jobschedule ... msdb.dbo.sp_add_jobserver ... (You can see an example by right clicking a scheduled job and selecting "Script Job as- Create To".) AND you can use sp_start_job to execute the job immediately, effectively running SSIS packages on demand. Question: does anyone know of any msdb.dbo.[...] stored procedures that simply allow you to run SSIS packages on the fly without using sp_cmdshell directly, or some easier approach?

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  • Round date to 10 minutes interval

    - by Peter Lang
    I have a DATE column that I want to round to the next-lower 10 minute interval in a query (see example below). I managed to do it by truncating the seconds and then subtracting the last digit of minutes. WITH test_data AS ( SELECT TO_DATE('2010-01-01 10:00:00', 'YYYY-MM-DD HH24:MI:SS') d FROM dual UNION SELECT TO_DATE('2010-01-01 10:05:00', 'YYYY-MM-DD HH24:MI:SS') d FROM dual UNION SELECT TO_DATE('2010-01-01 10:09:59', 'YYYY-MM-DD HH24:MI:SS') d FROM dual UNION SELECT TO_DATE('2010-01-01 10:10:00', 'YYYY-MM-DD HH24:MI:SS') d FROM dual UNION SELECT TO_DATE('2099-01-01 10:00:33', 'YYYY-MM-DD HH24:MI:SS') d FROM dual ) -- #end of test-data SELECT d, TRUNC(d, 'MI') - MOD(TO_CHAR(d, 'MI'), 10) / (24 * 60) FROM test_data And here is the result: 01.01.2010 10:00:00    01.01.2010 10:00:00 01.01.2010 10:05:00    01.01.2010 10:00:00 01.01.2010 10:09:59    01.01.2010 10:00:00 01.01.2010 10:10:00    01.01.2010 10:10:00 01.01.2099 10:00:33    01.01.2099 10:00:00 Works as expected, but is there a better way? EDIT: I was curious about performance, so I did the following test with 500.000 rows and (not really) random dates. I am going to add the results as comments to the provided solutions. DECLARE t TIMESTAMP := SYSTIMESTAMP; BEGIN FOR i IN ( WITH test_data AS ( SELECT SYSDATE + ROWNUM / 5000 d FROM dual CONNECT BY ROWNUM <= 500000 ) SELECT TRUNC(d, 'MI') - MOD(TO_CHAR(d, 'MI'), 10) / (24 * 60) FROM test_data ) LOOP NULL; END LOOP; dbms_output.put_line( SYSTIMESTAMP - t ); END; This approach took 03.24 s.

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