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  • What are the benefits of left outer join vs nested aggregate selects to find the newest rows in a table?

    - by RenderIn
    I'm doing: select * from mytable y where y.year = (select max(yi.year) from mytable yi where yi.person = y.person) Is that better or worse from a performance aspect than: select y.* from mytable y left outer join mytable y2 on y.year < y2.year and y.person = y2.person where y2.year is null The explain plan/anecdotal evidence is inconclusive so I am wondering if in general one is better than the other.

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  • Sqlserver 2005 Replication issue

    - by Francesco
    Hi, I have a peer to peer Merge Replication from two Sqlserver 2005. The first Sqlserver is both the publisher and distribuitor. All works fine but if the VPN goes down for a couple of hours the replication goes down too and I need to manually restart the sqlserver agent. In the Sqlserver Agent properties I have set the two option about the agent failover but nothing. How I can set an automatic restart of sqlserver agent when the VPN goes down? Thanks

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  • Should I include user_id in multiple tables?

    - by Drarok
    I'm at the planning stages of a multi-user application where each user will only have access their own data. There'll be a few tables that relate to each other, so I could use JOINs to ensure they're accessing only their data, but should I include user_id in each table? Would this be faster? It would certainly make some of the queries easier in the long run. Thanks!

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  • Select from multiple tables, remove duplicates

    - by staze
    I have two tables in a SQLite DB, and both have the following fields: idnumber, firstname, middlename, lastname, email, login One table has all of these populated, the other doesn't have the idnumber, or middle name populated. I'd LIKE to be able to do something like: select idnumber, firstname, middlename, lastname, email, login from users1,users2 group by login; But I get an "ambiguous" error. Doing something like: select idnumber, firstname, middlename, lastname, email, login from users1 union select idnumber, firstname, middlename, lastname, email, login from users2; LOOKS like it works, but I see duplicates. my understanding is that union shouldn't allow duplicates, but maybe they're not real duplicates since the second user table doesn't have all the fields populated (e.g. "20, bob, alan, smith, [email protected], bob" is not the same as "NULL, bob, NULL, smith, [email protected], bob"). Any ideas? What am I missing? All I want to do is dedupe based on "login". Thanks!

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  • how relate one table to another for future records

    - by Sinan
    I have a games table which holds the data about a game. Then another table which holds the data about news. So far so good. First I thought about creating a junction table for game_news so I could relate news to games. This way works as intended when the game exists. So whenever I insert a news I can relate it to a game using the junction table. However there are cases when there is news about game but the game isn't published and it doesn't exists. So my question would be; is there a way to relate these news to a particular game when the game record is created. What is the best way to do this? Any ideas?

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  • Unique identifiers for users

    - by Christopher McCann
    If I have a table of a hundred users normally I would just set up an auto-increment userID column as the primary key. But if suddenly we have a million users or 5 million users then that becomes really difficult because I would want to start becoming more distributed in which case an auto-increment primary key would be useless as each node would be creating the same primary keys. Is the solution to this to use natural primary keys? I am having a real hard time thinking of a natural primary key for this bunch of users. The problem is they are all young people so they do not have national insurance numbers or any other unique identifier I can think of. I could create a multi-column primary key but there is still a chance, however miniscule of duplicates occurring. Does anyone know of a solution? Thanks

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  • What is the proper way to create a recursive entity in the Entity Framework?

    - by Orion Adrian
    I'm currently using VS 2010 RC, and I'm trying to create a model that contains a recursive self-referencing entity. Currently when I import the entity from the model I get an error indicating that the parent property cannot be part of the association because it's set to 'Computed' or 'Identity', though I'm not sure why it does it that way. I've been hand-editing the file to get around that error, but then the model simply doesn't work. What is the proper way to get recursive entities to work in the Entity Framework. CREATE TABLE [dbo].[Appointments]( [AppointmentId] [int] IDENTITY(1,1) NOT NULL, [Description] [nvarchar](1024) NULL, [Start] [datetime] NOT NULL, [End] [datetime] NOT NULL, [Username] [varchar](50) NOT NULL, [RecurrenceRule] [nvarchar](1024) NULL, [RecurrenceState] [varchar](20) NULL, [RecurrenceParentId] [int] NULL, [Annotations] [nvarchar](50) NULL, [Application] [nvarchar](100) NOT NULL, CONSTRAINT [PK_Appointments] PRIMARY KEY CLUSTERED ( [AppointmentId] ASC ) ) GO ALTER TABLE [dbo].[Appointments] WITH CHECK ADD CONSTRAINT [FK_Appointments_ParentAppointments] FOREIGN KEY([RecurrenceParentId]) REFERENCES [dbo].[Appointments] ([AppointmentId]) GO ALTER TABLE [dbo].[Appointments] CHECK CONSTRAINT [FK_Appointments_ParentAppointments] GO

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  • Using outer query result in a subquery in postgresql

    - by brad
    I have two tables points and contacts and I'm trying to get the average points.score per contact grouped on a monthly basis. Note that points and contacts aren't related, I just want the sum of points created in a month divided by the number of contacts that existed in that month. So, I need to sum points grouped by the created_at month, and I need to take the count of contacts FOR THAT MONTH ONLY. It's that last part that's tricking me up. I'm not sure how I can use a column from an outer query in the subquery. I tried something like this: SELECT SUM(score) AS points_sum, EXTRACT(month FROM created_at) AS month, date_trunc('MONTH', created_at) + INTERVAL '1 month' AS next_month, (SELECT COUNT(id) FROM contacts WHERE contacts.created_at <= next_month) as contact_count FROM points GROUP BY month, next_month ORDER BY month So, I'm extracting the actual month that my points are being summed, and at the same time, getting the beginning of the next_month so that I can say "Get me the count of contacts where their created at is < next_month" But it complains that column next_month doesn't exist This is understandable as the subquery knows nothing about the outer query. Qualifying with points.next_month doesn't work either. So can someone point me in the right direction of how to achieve this? Tables: Points score | created_at 10 | "2011-11-15 21:44:00.363423" 11 | "2011-10-15 21:44:00.69667" 12 | "2011-09-15 21:44:00.773289" 13 | "2011-08-15 21:44:00.848838" 14 | "2011-07-15 21:44:00.924152" Contacts id | created_at 6 | "2011-07-15 21:43:17.534777" 5 | "2011-08-15 21:43:17.520828" 4 | "2011-09-15 21:43:17.506452" 3 | "2011-10-15 21:43:17.491848" 1 | "2011-11-15 21:42:54.759225" sum, month and next_month (without the subselect) sum | month | next_month 14 | 7 | "2011-08-01 00:00:00" 13 | 8 | "2011-09-01 00:00:00" 12 | 9 | "2011-10-01 00:00:00" 11 | 10 | "2011-11-01 00:00:00" 10 | 11 | "2011-12-01 00:00:00"

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  • How to differentiate between two similar fields in Linq Join tables

    - by Azhar
    How to differentiate between two select new fields e.g. Description c.Description and lt.Description DataTable lDt = new DataTable(); try { lDt.Columns.Add(new DataColumn("AreaTypeID", typeof(Int32))); lDt.Columns.Add(new DataColumn("CategoryRef", typeof(Int32))); lDt.Columns.Add(new DataColumn("Description", typeof(String))); lDt.Columns.Add(new DataColumn("CatDescription", typeof(String))); EzEagleDBDataContext lDc = new EzEagleDBDataContext(); var lAreaType = (from lt in lDc.tbl_AreaTypes join c in lDc.tbl_AreaCategories on lt.CategoryRef equals c.CategoryID where lt.AreaTypeID== pTypeId select new { lt.AreaTypeID, lt.Description, lt.CategoryRef, c.Description }).ToArray(); for (int j = 0; j< lAreaType.Count; j++) { DataRow dr = lDt.NewRow(); dr["AreaTypeID"] = lAreaType[j].LandmarkTypeID; dr["CategoryRef"] = lAreaType[j].CategoryRef; dr["Description"] = lAreaType[j].Description; dr["CatDescription"] = lAreaType[j].; lDt.Rows.Add(dr); } } catch (Exception ex) { }

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  • select rows with column that is not null?

    - by fayer
    by default i have one column in mysql table to be NULL. i want to select some rows but only if the field value in that column is not NULL. what is the correct way of typing it? $query = "SELECT * FROM names WHERE id = '$id' AND name != NULL"; is this correct?

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  • Any way to speed up this hierarchical query?

    - by RenderIn
    I've got a serious performance problem with a hierarchical query that I can't seem to fix. I am modeling several organization charts in my database, each representing a virtual organization within our company. For example, we have several temporary committees that are created from time to time and there may be a Committee Organizer role at the top of this virtual hierarchy, with several people assigned to the Committee Member role beneath the organizer. Some of our virtual organizations have many levels and several branches at each level. I have a single table in which I represent all the role assignments. i.e. a ROLE_ID column and a PARENT_ROLE_ID column which is a foreign key to the ROLE_ID column. For each assignment we also store as a column the location in the company where this person has the assignment. For example, the Committee Organizer would have a company-level/ CEO assignment, while the committee members would have department-level assignments such as ACCOUNTING, MARKETING, etc. So to model the organizer/member relationship for two individuals we would have: ROLE_ID = 4 PARENT_ROLE_ID = NULL EMPLOYEE_NUMBER = 213423 COMPANY_LOCATION = CEO ROLE_ID = 5 PARENT_ROLE_ID = 4 EMPLOYEE_NUMBER = 838221 COMPANY_LOCATION = ACCOUNTING Here's where things get tricky. I have an application that every person in the organization can log in to. When they log in they should be able to view all the virtual organizations in our company. e.g. the committee members should be able to see the committee organizer and vice-versa. However, only the committee organizer should be able to edit the committee members. The difficulty is in determining whether an individual (who can have multiple role assignments) has edit access for each other assignment. While this seems simple in the example, consider a virtual organization in which we have President at the top, 5 departments directly beneath him, 2 subdepartments below each department. We only want people in the Accounting department to be able to edit individuals in the subdepartments belonging to the Accounting department. They should not have edit access to anybody in the Marketing department or its subdepartments. To determine edit access when a user views a virtual organization in our company I run a query that executes two inline views: A) Hierarchically query for all assignments in this virtual organization and using SYS_CONNECT_BY_PATH to store the entire path to each user/role/company_location and B) Hierarchically retrieve all the assignments the individual logged in has and using the SYS_CONNECT_BY_PATH to store the entire path to each of these assignments. The result of the query is all the records from A) plus a boolean determined by joining with B) which flags whether the logged in user has edit access for each record. Indexes don't seem to be helping... it simply appears that there is too much processing going on to separate all the records and then determine edit access. One issue is that I can't store the SYS_CONNECT_BY_PATH and index it... determining whether an individual record has edit access consists of comparing if: test_record_sys_path LIKE individual_record_sys_path || '%' Is a materialized view the answer?

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  • PIVOT / UNPIVOT IN SQL 2008

    - by Nev_Rahd
    Hello I got child / parent tables as below. MasterTable: MasterID, Description ChildTable ChildID, MasterID, Description. Using PIVOT / UNPIVOT how can i get result as below in single row. if (MasterID : 1 got x child records) MasterID, ChildID1, Description1, ChildID2, Description2....... ChildIDx, Descriptionx Thanks

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  • Using Linq2Sql to insert data into multiple tables using an auto incremented primary key

    - by Thomas
    I have a Customer table with a Primary key (int auto increment) and an Address table with a foreign key to the Customer table. I am trying to insert both rows into the database in one nice transaction. using (DatabaseDataContext db = new DatabaseDataContext()) { Customer newCustomer = new Customer() { Email = customer.Email }; Address b = new Address() { CustomerID = newCustomer.CustomerID, Address1 = billingAddress.Address1 }; db.Customers.InsertOnSubmit(newCustomer); db.Addresses.InsertOnSubmit(b); db.SubmitChanges(); } When I run this I was hoping that the Customer and Address table automatically had the correct keys in the database since the context knows this is an auto incremented key and will do two inserts with the right key in both tables. The only way I can get this to work would be to do SubmitChanges() on the Customer object first then create the address and do SubmitChanges() on that as well. This would create two roundtrips to the database and I would like to see if I can do this in one transaction. Is it possible? Thanks

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  • Obtaining Current Fiscal Year from Hierarchy with MDX

    - by Robert Iver
    I'm building a report in Reporting Services 2005 based on a SSAS 2005 cube. The basic idea of the report is that they want to see sales for this fiscal year to date vs. last year sales year to date. It sounds simple, but being that this is my first "real" report based on SSAS, I'm having a hell of a time. First, how would one calculate the current fiscal year, quarter, or month. I have a Fiscal Date Hierarchy with all that information in it, but I can't figure out how to say: "Based on today's date, find the current fiscal year, quarter, and month." My second, but slightly smaller problem, is getting last years sales vs. this years sales. I have seen MANY examples on how to do this, but they all assume that you select the date manually. Since this is a report and will run pretty much on it's own, I need a way to insert the "current" fiscal year, quarter, and month into the PERIODSTODATE or PARALLELPERIOD functions to get what I want. So, I'm begging for your help on this one. I have to have this report done by tomorrow monring and I'm beginning to freak out a bit. Thanks in advance.

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  • Strange: Planner takes decision with lower cost, but (very) query long runtime

    - by S38
    Facts: PGSQL 8.4.2, Linux I make use of table inheritance Each Table contains 3 million rows Indexes on joining columns are set Table statistics (analyze, vacuum analyze) are up-to-date Only used table is "node" with varios partitioned sub-tables Recursive query (pg = 8.4) Now here is the explained query: WITH RECURSIVE rows AS ( SELECT * FROM ( SELECT r.id, r.set, r.parent, r.masterid FROM d_storage.node_dataset r WHERE masterid = 3533933 ) q UNION ALL SELECT * FROM ( SELECT c.id, c.set, c.parent, r.masterid FROM rows r JOIN a_storage.node c ON c.parent = r.id ) q ) SELECT r.masterid, r.id AS nodeid FROM rows r QUERY PLAN ----------------------------------------------------------------------------------------------------------------------------------------------------------------- CTE Scan on rows r (cost=2742105.92..2862119.94 rows=6000701 width=16) (actual time=0.033..172111.204 rows=4 loops=1) CTE rows -> Recursive Union (cost=0.00..2742105.92 rows=6000701 width=28) (actual time=0.029..172111.183 rows=4 loops=1) -> Index Scan using node_dataset_masterid on node_dataset r (cost=0.00..8.60 rows=1 width=28) (actual time=0.025..0.027 rows=1 loops=1) Index Cond: (masterid = 3533933) -> Hash Join (cost=0.33..262208.33 rows=600070 width=28) (actual time=40628.371..57370.361 rows=1 loops=3) Hash Cond: (c.parent = r.id) -> Append (cost=0.00..211202.04 rows=12001404 width=20) (actual time=0.011..46365.669 rows=12000004 loops=3) -> Seq Scan on node c (cost=0.00..24.00 rows=1400 width=20) (actual time=0.002..0.002 rows=0 loops=3) -> Seq Scan on node_dataset c (cost=0.00..55001.01 rows=3000001 width=20) (actual time=0.007..3426.593 rows=3000001 loops=3) -> Seq Scan on node_stammdaten c (cost=0.00..52059.01 rows=3000001 width=20) (actual time=0.008..9049.189 rows=3000001 loops=3) -> Seq Scan on node_stammdaten_adresse c (cost=0.00..52059.01 rows=3000001 width=20) (actual time=3.455..8381.725 rows=3000001 loops=3) -> Seq Scan on node_testdaten c (cost=0.00..52059.01 rows=3000001 width=20) (actual time=1.810..5259.178 rows=3000001 loops=3) -> Hash (cost=0.20..0.20 rows=10 width=16) (actual time=0.010..0.010 rows=1 loops=3) -> WorkTable Scan on rows r (cost=0.00..0.20 rows=10 width=16) (actual time=0.002..0.004 rows=1 loops=3) Total runtime: 172111.371 ms (16 rows) (END) So far so bad, the planner decides to choose hash joins (good) but no indexes (bad). Now after doing the following: SET enable_hashjoins TO false; The explained query looks like that: QUERY PLAN ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- CTE Scan on rows r (cost=15198247.00..15318261.02 rows=6000701 width=16) (actual time=0.038..49.221 rows=4 loops=1) CTE rows -> Recursive Union (cost=0.00..15198247.00 rows=6000701 width=28) (actual time=0.032..49.201 rows=4 loops=1) -> Index Scan using node_dataset_masterid on node_dataset r (cost=0.00..8.60 rows=1 width=28) (actual time=0.028..0.031 rows=1 loops=1) Index Cond: (masterid = 3533933) -> Nested Loop (cost=0.00..1507822.44 rows=600070 width=28) (actual time=10.384..16.382 rows=1 loops=3) Join Filter: (r.id = c.parent) -> WorkTable Scan on rows r (cost=0.00..0.20 rows=10 width=16) (actual time=0.001..0.003 rows=1 loops=3) -> Append (cost=0.00..113264.67 rows=3001404 width=20) (actual time=8.546..12.268 rows=1 loops=4) -> Seq Scan on node c (cost=0.00..24.00 rows=1400 width=20) (actual time=0.001..0.001 rows=0 loops=4) -> Bitmap Heap Scan on node_dataset c (cost=58213.87..113214.88 rows=3000001 width=20) (actual time=1.906..1.906 rows=0 loops=4) Recheck Cond: (c.parent = r.id) -> Bitmap Index Scan on node_dataset_parent (cost=0.00..57463.87 rows=3000001 width=0) (actual time=1.903..1.903 rows=0 loops=4) Index Cond: (c.parent = r.id) -> Index Scan using node_stammdaten_parent on node_stammdaten c (cost=0.00..8.60 rows=1 width=20) (actual time=3.272..3.273 rows=0 loops=4) Index Cond: (c.parent = r.id) -> Index Scan using node_stammdaten_adresse_parent on node_stammdaten_adresse c (cost=0.00..8.60 rows=1 width=20) (actual time=4.333..4.333 rows=0 loops=4) Index Cond: (c.parent = r.id) -> Index Scan using node_testdaten_parent on node_testdaten c (cost=0.00..8.60 rows=1 width=20) (actual time=2.745..2.746 rows=0 loops=4) Index Cond: (c.parent = r.id) Total runtime: 49.349 ms (21 rows) (END) - incredibly faster, because indexes were used. Notice: Cost of the second query ist somewhat higher than for the first query. So the main question is: Why does the planner make the first decision, instead of the second? Also interesing: Via SET enable_seqscan TO false; i temp. disabled seq scans. Than the planner used indexes and hash joins, and the query still was slow. So the problem seems to be the hash join. Maybe someone can help in this confusing situation? thx, R.

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  • Best way to store sales tax information

    - by Seph
    When designing a stock management database system (sales / purchases) what would be the best way to store the various taxes and other such amounts? A few of the fields that could be saved are: Unit price excluding tax Unit price including tax Tax per item Total excluding tax (rounded to 2 decimals) Total including tax (rounded to 2 decimals) Total tax (rounded to 2 decimals) Currently the most reasonable solution so far is storing down (roughly) item, quantity, total excluding tax (rounded) and the total tax (rounded). Can anyone suggest some better way of storing this details for a generic system? Also, given the system needs to be robust, what should be done if there were multiple tax values (eg: state and city) which might need to be separated, in this case a separate table would be in order, but would it be considered excessive to just have a rowID and some taxID mapping to a totalTax column?

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  • How to sort a gridview once a radio button is selected

    - by metashockwave
    I'm trying to sort records in the gridview right after a radio button is selected. My approach is with the dataview, but because the dataset variable doesn't survive a round trip to the server, I don't know how to make this happen. please help! Public Sub GetCustomers() db.RunProcedure("usp_customers_get_all") db.doSort(radList.SelectedValue) gvCustomers.DataSource = db.MyView End Sub Protected Sub radList_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles radList.SelectedIndexChanged If radList.SelectedValue = 0 Then db.doSort(0) gvCustomers.DataSource = db.MyView End If If radList.SelectedValue = 1 Then db.doSort(1) gvCustomers.DataSource = db.MyView End If End Sub Public Sub doSort(ByVal strIn As Integer) If strIn = 0 Then MyView.Sort = "lastname, firstname" Else MyView.Sort = "username" End If End Sub Public Sub RunProcedure(ByVal strName As String) Dim objConnection As New SqlConnection(mstrConnection) Dim mdbDataAdapter As New SqlDataAdapter(strName, objConnection) Try mdbDataAdapter.SelectCommand.CommandType = CommandType.StoredProcedure Me.mDataset.Clear() mdbDataAdapter.Fill(mDataset, "tblCustomers") MyView.Table = mDataset.Tables("tblCustomers") Catch ex As Exception Throw New Exception("stored procedure is " & strName.ToString & " error is " & ex.Message) End Try End Sub

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  • Hibernate Auto-Increment Setup

    - by dharga
    How do I define an entity for the following table. I've got something that isn't working and I just want to see what I'm supposed to do. USE [BAMPI_TP_dev] GO SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO SET ANSI_PADDING ON GO CREATE TABLE [dbo].[MemberSelectedOptions]( [OptionId] [int] NOT NULL, [SeqNo] [smallint] IDENTITY(1,1) NOT NULL, [OptionStatusCd] [char](1) NULL ) ON [PRIMARY] GO SET ANSI_PADDING OFF This is what I have already that isn't working. @Entity @Table(schema="dbo", name="MemberSelectedOptions") public class MemberSelectedOption extends BampiEntity implements Serializable { @Embeddable public static class MSOPK implements Serializable { private static final long serialVersionUID = 1L; @Column(name="OptionId") int optionId; @GeneratedValue(strategy=GenerationType.IDENTITY) @Column(name="SeqNo", unique=true, nullable=false) BigDecimal seqNo; //Getters and setters here... } private static final long serialVersionUID = 1L; @EmbeddedId MSOPK pk = new MSOPK(); @Column(name="OptionStatusCd") String optionStatusCd; //More Getters and setters here... } I get the following ST. [5/25/10 15:49:40:221 EDT] 0000003d JDBCException E org.slf4j.impl.JCLLoggerAdapter error Cannot insert explicit value for identity column in table 'MemberSelectedOptions' when IDENTITY_INSERT is set to OFF. [5/25/10 15:49:40:221 EDT] 0000003d AbstractFlush E org.slf4j.impl.JCLLoggerAdapter error Could not synchronize database state with session org.hibernate.exception.SQLGrammarException: could not insert: [com.bob.proj.ws.model.MemberSelectedOption] at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:90) at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66) at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2285) at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2678) at org.hibernate.action.EntityInsertAction.execute(EntityInsertAction.java:79) at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:279) at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:263) at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:167) at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:321) at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:50) at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1028) at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:366) at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:137) at com.bcbst.bamp.ws.dao.MemberSelectedOptionDAOImpl.saveMemberSelectedOption(MemberSelectedOptionDAOImpl.java:143) at com.bcbst.bamp.ws.common.AlertReminder.saveMemberSelectedOptions(AlertReminder.java:76) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)

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  • Converting delimited string to multiple values in mysql

    - by epo
    I have a mysql legacy table which contains an client identifier and a list of items, the latter as a comma-delimited string. E.g. "xyz001", "foo,bar,baz". This is legacy stuff and the user insists on being able to edit a comma delimited string. They now have a requirement for a report table with the above broken into separate rows, e.g. "xyz001", "foo" "xyz001", "bar" "xyz001", "baz" Breaking the string into substrings is easily doable and I have written a procedure to do this by creating a separate table, but that requires triggers to deal with deletes, updates and inserts. This query is required rarely (say once a month) but has to be absolutely up to date when it is run, so e.g. the overhead of triggers is not warranted and scheduled tasks to create the table might not be timely enough. Is there any way to write a function to return a table or a set so that I can join the identifier with the individual items on demand?

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  • Calling sp and Performance strategy.

    - by Costa
    Hi I find my self in a situation where I have to choose between either creating a new sp in database and create the middle layer code. so loose some precious development time. also the procedure is likely to contain some joins. Or use two existing sp(s), the problem of this approach is that I am doing two round trips to database. which can be poor performance especially if I have database in another server. Which approach you will go?, and why? thanks

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  • MySQL slow query

    - by andrhamm
    SELECT items.item_id, items.category_id, items.title, items.description, items.quality, items.type, items.status, items.price, items.posted, items.modified, zip_code.state_prefix, zip_code.city, books.isbn13, books.isbn10, books.authors, books.publisher FROM ( ( items LEFT JOIN bookitems ON items.item_id = bookitems.item_id ) LEFT JOIN books ON books.isbn13 = bookitems.isbn13 ) LEFT JOIN zip_code ON zip_code.zip_code = items.item_zip WHERE items.rid = $rid` I am running this query to get the list of a user's items and their location. The zip_code table has over 40k records and this might be the issue. It currently takes up to 15 seconds to return a list of about 20 items! What can I do to make this query more efficient?

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  • How do I save an object that contains and EntitySet?

    - by Pete
    Say I have an User (mapped to a User table) and the Edit view (in MVC) displays a multiselectlist of Modules (mapped to a Modules table) that user can access, with the Modules pre-selected based on the User's EntitySet of Modules. I have tried saving the User then deleting all User_Modules manually and adding them back based on what's selected on submit, but the User has a null EntitySet for User.User_Modules. I cannot find the correct way to handle this scenario anywhere online. Can anyone help?

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