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  • Struggling to create correct relationships in MS Access

    - by Yandawl
    http://img714.imageshack.us/img714/7820/croppercapture1.png Basically: an award(course) has many units, which can be either optional or core(mandatory), depending on the award. So for example: the unit 'Advanced Software Engineering' maybe a core unit for the award 'Software Engineering BSc' but only an optional unit for the course 'Web Technology BSc'. I've used flags for that purpose. A student is enrolled on an award so I need to get a complete list of core and optional units (bearing in mind that a student chooses 1 out of many possible optional units). Also, these units have events, e.g, a lecture, workshop or seminar, etc. and those events have sessions or instances of events where students enrolled on that particular unit are required to attend, and those attendances are stored in a separate table to form a register. So I need a hierarchy of expanding the tables something like this I guess: Awards - Students - Units - Sessions - Attendances Any help with this would be appreciated... It's blowing my mind and I'm really close to going insane! My tutor didn't spot I'd got it wrong when I showed my original data model to him and it's due in next week! Thank you :D

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  • How do views reduce code duplication?

    - by Debuger
    Hi! I read something like this about db views: Views are incredibly powerful and useful for one reason that stands out above all the other very good reasons. They reduce code duplication. That is, in most cases, the bottom line. If a query will be used in three or more places, then a view will drastically simplify your changes if the schema or query parameters change. I once had to edit 22 stored procedures to change some query logic. If the original architecture had utilized views, then I would have had only three changes. Can anyone explain to me how it works, and maybe give me some examples? Best regards!

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  • Problem with duplicates in a SQL Join

    - by Chris Ballance
    I have the following result set from a join of three tables, an articles table, a products table, an articles to products mapping table. I would like to have the results with duplicates removed similar to a select distinct on content id. Current result set: [ContendId] [Title] [productId] 1 article one 2 1 article one 3 1 article one 9 4 article four 1 4 article four 10 4 article four 14 5 article five 1 6 article six 8 6 article six 10 6 article six 11 6 article six 13 7 article seven 14 Desired result set: [ContendId] [Title] [productId] 1 article one * 4 article four * 5 article five * 6 article six * 7 article seven * Here is condensed example of the relevant SQL: IF EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'tempdb.dbo.products') AND type = (N'U')) drop table tempdb.dbo.products go CREATE TABLE tempdb.dbo.products ( productid int, productname varchar(255) ) go IF EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'articles') AND type = (N'U')) drop table tempdb.dbo.articles go create table tempdb.dbo.articles ( contentid int, title varchar(255) ) IF EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'articles') AND type = (N'U')) drop table tempdb.dbo.articles go create table tempdb.dbo.articles ( contentid int, title varchar(255) ) IF EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'articleproducts') AND type = (N'U')) drop table tempdb.dbo.articleproducts go create table tempdb.dbo.articleproducts ( contentid int, productid int ) insert into tempdb.dbo.products values (1,'product one'), (2,'product two'), (3,'product three'), (4,'product four'), (5,'product five'), (6,'product six'), (7,'product seven'), (8,'product eigth'), (9,'product nine'), (10,'product ten'), (11,'product eleven'), (12,'product twelve'), (13,'product thirteen'), (14,'product fourteen') insert into tempdb.dbo.articles VALUES (1,'article one'), (2, 'article two'), (3, 'article three'), (4, 'article four'), (5, 'article five'), (6, 'article six'), (7, 'article seven'), (8, 'article eight'), (9, 'article nine'), (10, 'article ten') INSERT INTO tempdb.dbo.articleproducts VALUES (1,2), (1,3), (1,9), (4,1), (4,10), (4,14), (5,1), (6,8), (6,10), (6,11), (6,13), (7,14) GO select DISTINCT(a.contentid), a.title, p.productid from articles a JOIN articleproducts ap ON a.contentid = ap.contentid JOIN products p ON a.contentid = ap.contentid AND p.productid = ap.productid ORDER BY a.contentid

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  • mongodb php finding a subobject and removing it, $inc other subobject

    - by Mark
    I'm trying to delete the subobject 'apples' from my documents and update the 'fruitInventory' property, decrease by the amount of apples. I'm confused on how to proceed, should I use dot notation or do a full text search for apples? I don't know if this matters but you can assume apples will always be in field 1. // Document 1 { "1": { "apples": 3, "fruitInventory": 21, "oranges": 12, "kiwis": 3, "lemons": 3 }, "2": { "bananas": 4, "fruitInventory": 12, "oranges": 8, }, "_id": "1" } // Document 2 { "1": { "apples": 5, "fruitInventory": 10, "oranges": 2, "pears": 3 }, "2": { "bananas": 4, "fruitInventory": 6, "cherries": 2, }, "_id": "2" } Result should be like this: // Document 1 { "1": { "fruitInventory": 18, "oranges": 12, "kiwis": 3, "lemons": "3" }, "2": { "bananas": 4, "fruitInventory": 12, "oranges": 8, }, "_id": "1" } // Document 2 { "1": { "fruitInventory": 5, "oranges": "2", "pears": "3" }, "2": { "bananas": 4, "fruitInventory": 6, "cherries": 2, }, "_id": "2" } Thanks in advance for your help.

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  • MySQL Connection error in spring MVC

    - by nidhi
    i am working on spring MVC facing the following exception while connecting to my sql. Blocorg.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Communications link failure The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.) at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:80) at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:572) at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:636) at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:665) at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:673) at org.springframework.jdbc.core.JdbcTemplate.queryForObject(JdbcTemplate.java:728) at org.springframework.jdbc.core.JdbcTemplate.queryForObject(JdbcTemplate.java:744) at org.springframework.jdbc.core.JdbcTemplate.queryForInt(JdbcTemplate.java:775) at com.trackmeetings.dao.InboxDAOImpl.getNotificationsCount(InboxDAOImpl.java:51) at com.trackmeetings.service.InboxService.getNotificationsCount(InboxService.java:56) at com.trackmeetings.controller.HomePageController.getLogInUserDetails(HomePageController.java:80) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:175) at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:421) at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:409) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:774) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:719) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:644) at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:560) at javax.servlet.http.HttpServlet.service(HttpServlet.java:710) at javax.servlet.http.HttpServlet.service(HttpServlet.java:803) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at com.trackmeetings.util.NoCacheFilter.doFilter(NoCacheFilter.java:56) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447) at java.lang.Thread.run(Thread.java:680) Caused by: org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Communications link failure The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.) at org.apache.commons.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1225) at org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource.java:880) at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:111) at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:77) ... 38 more Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failurekquote how can i resolve this. please help,

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  • Implementing Model-level caching

    - by Byron
    I was posting some comments in a related question about MVC caching and some questions about actual implementation came up. How does one implement a Model-level cache that works transparently without the developer needing to manually cache, yet still remains efficient? I would keep my caching responsibilities firmly within the model. It is none of the controller's or view's business where the model is getting data. All they care about is that when data is requested, data is provided - this is how the MVC paradigm is supposed to work. (Source: Post by Jarrod) The reason I am skeptical is because caching should usually not be done unless there is a real need, and shouldn't be done for things like search results. So somehow the Model itself has to know whether or not the SELECT statement being issued to it worthy of being cached. Wouldn't the Model have to be astronomically smart, and/or store statistics of what is being most often queried over a long period of time in order to accurately make a decision? And wouldn't the overhead of all this make the caching useless anyway? Also, how would you uniquely identify a query from another query (or more accurately, a resultset from another resultset)? What about if you're using prepared statements, with only the parameters changing according to user input? Another poster said this: I would suggest using the md5 hash of your query combined with a serialized version of your input arguments. This would require twice the number of serialization options. I was under the impression that serialization was quite expensive, and for large inputs this might be even worse than just re-querying. And is the minuscule chance of collision worth worrying about? Conceptually, caching in the Model seems like a good idea to me, but it seems in practicality the developer should have direct control over caching and write it into the controller. Thoughts/ideas? Edit: I'm using PHP and MySQL if that helps to narrow your focus.

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  • Event triggering in server-side scripts

    - by Qiao
    In SO, when your question got answer. or you got new badge, event is triggered. Or when you got new PM in forum, it also lets you know by alerting message. You see message that something happened with your account when you enter site for first time after this event. How is this implemented? How do scripts know, that they have something new to show you?

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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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  • How to move an element in a sorted list and keep the CouchDb write "atomic"

    - by karlthorwald
    I have elements of a list in couchdb documents. Let's say these are 3 elements in 3 documents: { "id" : "783587346", "type" : "aList", "content" : "joey", "sort" : 100.0 } { "id" : "358734ff6", "type" : "aList", "content" : "jill", "sort" : 110.0 } { "id" : "abf587346", "type" : "aList", "content" : "jack", "sort" : 120.0 } A view retrieves all "aList" documents and displays them sorted by "sort". Now I want to move the elements, when I want to move "jack" to the middle, I could do this atomic in one write and change it's sort key to 105.0. The view now returns the documents in the new sort order. After a lot of sorting I could end up with sort keys like 50.99999 and 50.99998 after some years and in extreme situations run out of digits? What can you recommend, is there a better way to do this? I'd rather keep the elements in seperate documents. Different users might edit different elements in parallel (which also can get tricky). Maybe there is a much better way?

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  • SQL: How do I INSERT primary key values from two tables INTO a master table.

    - by Stefan
    Hello, I would appreciate some help with an SQL statement I really can't get my head around. What I want to do is fairly simple, I need to take the values from two different tables and copy them into an master table when a new row is inserted into one of the two tables. The problem is perhaps best explained like this: I have three tables, productcategories, regioncategories and mastertable. --------------------------- TABLE: PRODUCTCATEGORIES --------------------------- COLUMNS: CODE | DESCRIPTION --------------------------- VALUES: BOOKS | Books --------------------------- --------------------------- TABLE: REGIONCATEGORIES --------------------------- COLUMNS: CODE | DESCRIPTION --------------------------- VALUES: EU | European Union --------------------------- --------------------------- TABLE: MASTERTABLE --------------------------- COLUMNS: REGION | PRODUCT --------------------------- VALUES: EU | BOOKS --------------------------- I want the values to be inserted like this when a new row is created in either productcategories or regioncategories. New row is created. --------------------------- TABLE: PRODUCTCATEGORIES --------------------------- COLUMNS: CODE | DESCRIPTION --------------------------- VALUES: BOOKS | Books --------------------------- VALUES: DVD | DVDs --------------------------- And a SQL statement copies the new values into the mastertable. --------------------------- TABLE: MASTERTABLE --------------------------- COLUMNS: REGION | PRODUCT --------------------------- VALUES: EU | BOOKS --------------------------- VALUES: EU | DVD --------------------------- The same goes if a row is created in the regioncategories. New row. --------------------------- TABLE: REGIONCATEGORIES --------------------------- COLUMNS: CODE | DESCRIPTION --------------------------- VALUES: EU | European Union --------------------------- VALUES: US | United States --------------------------- Copied to the mastertable. --------------------------- TABLE: MASTERTABLE --------------------------- COLUMNS: REGION | PRODUCT --------------------------- VALUES: EU | BOOKS --------------------------- VALUES: EU | DVD --------------------------- VALUES: US | BOOKS --------------------------- VALUES: US | DVD --------------------------- I hope it makes sense. Thanks, Stefan

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  • Would this hack for per-object permissions in django work?

    - by Edward
    According to the documentation, a class can have the meta option permissions, described as such: Options.permissions Extra permissions to enter into the permissions table when creating this object. Add, delete and change permissions are automatically created for each object that has admin set. This example specifies an extra permission, can_deliver_pizzas: permissions = (("can_deliver_pizzas", "Can deliver pizzas"),) This is a list or tuple of 2-tuples in the format (permission_code, human_readable_permission_name). Would it be possible to define permissions at run time by: permissions = (("can_access_%s" % self.pk, / "Has access to object %s of type %s" % (self.pk,self.__name__)),) ?

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  • How do these user/userParam references relate to the Customer and Account lookups?

    - by marmalade
    In the following code example how do the user/userParam references relate to the Customer and Account lookups and what is the relationship between Customer and Account? // PersistenceManager pm = ...; Transaction tx = pm.currentTransaction(); User user = userService.currentUser(); List<Account> accounts = new ArrayList<Account>(); try { tx.begin(); Query query = pm.newQuery("select from Customer " + "where user == userParam " + "parameters User userParam"); List<Customer> customers = (List<Customer>) query.execute(user); query = pm.newQuery("select from Account " + "where parent-pk == keyParam " + "parameters Key keyParam"); for (Customer customer : customers) { accounts.addAll((List<Account>) query.execute(customer.key)); } } finally { if (tx.isActive()) { tx.rollback(); } }

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  • How do these user/userParam references relate to the Customer and Account lookups?

    - by plath
    In the following code example how do the user/userParam references relate to the Customer and Account lookups and what is the relationship between Customer and Account? // PersistenceManager pm = ...; Transaction tx = pm.currentTransaction(); User user = userService.currentUser(); List<Account> accounts = new ArrayList<Account>(); try { tx.begin(); Query query = pm.newQuery("select from Customer " + "where user == userParam " + "parameters User userParam"); List<Customer> customers = (List<Customer>) query.execute(user); query = pm.newQuery("select from Account " + "where parent-pk == keyParam " + "parameters Key keyParam"); for (Customer customer : customers) { accounts.addAll((List<Account>) query.execute(customer.key)); } } finally { if (tx.isActive()) { tx.rollback(); } }

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  • How to select top n rows from a datatable/dataview in asp.net

    - by skamale
    How to select top n rows from a datatable/dataview in asp.net.currently I am using the following code by passing the table and number of rows to get the records but is there a better way. public DataTable SelectTopDataRow(DataTable dt, int count) { DataTable dtn = dt.Clone(); for (int i = 0; i < count; i++) { dtn.ImportRow(dt.Rows[i]); } return dtn; }

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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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  • Erlang Mnesia Equivalent of SQL Select FROM WHERE Field IN (value1, value2, value3, ...)

    - by ErJab
    I have an mnesia table with fields say f1, f2, f3. Now if I were to select all the rows with the field value as V1, I would use mnesia:select and match specifications or a simple mnesia:match_object. Now I need to select all the rows which have V1, V2, V3 ... or Vn (a list of arbitrary length) as the value for field f1. In SQL I would do something like SELECT * FROM tablename WHERE f3 IN (V1, V2, V3, ... , Vn) How do I do this in mnesia?

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  • In symfony/doctrine's schema.yml, where should I put onDelete: CASCADE for a many-to-many relationsh

    - by nselikoff
    I have a many-to-many relationship defined in my Symfony (using doctrine) project between Orders and Upgrades (an Order can be associated with zero or more Upgrades, and an Upgrade can apply to zero or more Orders). # schema.yml Order: columns: order_id: {...} relations: Upgrades: class: Upgrade local: order_id foreign: upgrade_id refClass: OrderUpgrade Upgrade: columns: upgrade_id: {...} relations: Orders: class: Order local: upgrade_id foreign: order_id refClass: OrderUpgrade OrderUpgrade: columns: order_id: {...} upgrade_id: {...} I want to set up delete cascade behavior so that if I delete an Order or an Upgrade, all of the related OrderUpgrades are deleted. Where do I put onDelete: CASCADE? Usually I would put it at the end of the relations section, but that would seem to imply in this case that deleting Orders would cascade to delete Upgrades. Is Symfony + Doctrine smart enough to know what I'm wanting if I put onDelete: CASCADE in the above relations sections of schema.yml?

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  • Using a table-alias in Kohana queries?

    - by Aristotle
    I'm trying to run a simple query with $this->db in Kohana, but am running into some syntax issues when I try to use an alias for a table within my query: $result = $this->db ->select("ci.chapter_id, ci.book_id, ci.chapter_heading, ci.chapter_number") ->from("chapter_info ci") ->where(array("ci.chapter_number" => $chapter, "ci.book_id" => $book)) ->get(); It seems to me that this should work just fine. I'm stating that "chapter_info" ought to be known as "ci," yet this isn't taking for some reason. The error is pretty straight-forward: There was an SQL error: Table 'gb_data.chapter_info ci' doesn't exist - SELECT `ci`.`chapter_id`, `ci`.`book_id`, `ci`.`chapter_heading`, `ci`.`chapter_number` FROM (`chapter_info ci`) WHERE `ci`.`chapter_number` = 1 AND `ci`.`book_id` = 1 If I use the full table name, rather than an alias, I get the expected results without error. This requires me to write much more verbose queries, which isn't ideal. Is there some way to use shorter names for tables within Kohana's query-builder?

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  • does the order a composite key is defined matter?

    I have a table with (col1,col2) as a composite primary key. create table twokeytable(col1 int,col2 int,constraint twokeytable_pk primary key (col1,col2)); and another table with col3,col4 collumns witha composite foreign key(col3,col4) which references the(col1,col2) primary key. For some processing I need to drop the foreign key and primary constraints .While restoring the constraints does order of the keys matter?. are these same? create table fktwokeytable(col3 int,col4 int,constraint fkaddfaa_fk foreign key(col4,col3) references twokeytable(col1,col2)) and create table fktwokeytable(col3 int,col4 int,constraint fkaddfaa_fk foreign key(col3,col4) references twokeytable(col1,col2))

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  • Select count / duplicates

    - by mike
    Hello! I have a table with all U.S. zip codes. each row contains the city and state name for the zip code. I'm trying to get a list of cities that show up in multiple states. This wouldn't be a problem if there weren't X amount of zip codes in the same city... So basically, I just want to the city in a state to count as 1 instead of it counting the city/state 7 times because there are 2+ zip codes in that city/state... I'm not really sure how to do this. I know I need to use count but how do I tell the mysql to only count a given city/state combo as 1?

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  • ERD-CLASS design

    - by Mahesh
    Hello guyz,i am new to daatbase and class diagram.I just get scenarios from internet and try to develop ERD and Class Diagram for them.But the following scenario has caused me some problems, and i am not sure about my design. "Whenever an employee fills leave application form, the leave application should be appeared for approval to his/her team leader. Team Leader has the option to change the date of requested leave and to approve or reject the leave. Employee also has the option to change date of previously unapproved leaves or to cancel any of unapproved leave. In case of team leader, he can approve his own leaves. Management should be able to create categories of leaves like (Casual, Sick, Planned work, etc) and should be able to adjust the days allocated to each type of leave". I have identified these as entities for ERD 1) Employee(I think i dont need to make entity for Technical lead,since he is an employee) 2) LeaveHistory 3) LeaveCategory Plz correct me if the system need more classes or entities

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  • How to detect a pending JDO transaction?

    - by Stevko
    I believe I am getting JDO commit Exceptions due to the transactions nesting although I'm not sure. Will this detect the situation where I am starting a transaction when another is pending? PersistenceManager pm = PersistenceManagerFactory.get().getPersistenceManager(); assert pm.currentTransaction().isActive() == false : "arrrgh"; pm.currentTransaction().begin(); Is there a better or more reliable way?

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