Search Results

Search found 37647 results on 1506 pages for 'sql performance'.

Page 703/1506 | < Previous Page | 699 700 701 702 703 704 705 706 707 708 709 710  | Next Page >

  • Help with my application please! Can’t open image(s) with error: External component has thrown an ex

    - by Brandon
    I have an application written in C# I believe and it adds images to a SQL Server 2005 Database. It requires .NET 3.5 to be installed on my computer. I installed .NET 3.5 and setup a database. It runs fine but then once it gets to image 100 when running on one computer, It stops and gives me this error: Can't open image(s) with error: External component has thrown an exception.... When I run the program on my own computer I am able to reach 300 images but then it stops after 300 images and gives me Can't open image(s) with error: External component has thrown an exception.... error once again. please help!

    Read the article

  • Query "where clause" fails when calling a function

    - by guest1
    Hi All, I have a function in Access VBA that takes four parameters.The fourth parameter is a "where clause" that I use in an SQL statement inside the function. The function fails when I include the fourth parameter (where clause). When I remove this fourth parameter, the function just works fine. I am not sure if there is anything wrong with the syntax of the fourth parameter ? Please help. here is the function as called in the Query FunctionA('Table1','Field1',0.3,'Field2=#' & [Field2] & '# and Value3="' & [Value3] & '"') AS Duration_Field

    Read the article

  • Concurrency handling

    - by Lijo
    Hi, Suppose, I am about to start a project using ASP.NET and SQL Server 2005. I have to design the concurrency requirement for this application. I am planning to add a TimeStamp column in each table. While updating the tables I will check that the TimeStamp column is same, as it was selected. Will this approach be suffice? Or is there any shortcomings for this approach under any circumstances? Please advice. Thanks Lijo

    Read the article

  • Why does do this code do if(sz !=sz2) sz = sz2 !?!

    - by acidzombie24
    For the first time i created a linq to sql classes. I decided to look at the class and found this. What... why is it doing if(sz !=sz2) { sz = sz2; }. I dont understand. Why isnt the set generated as this._Property1 = value? private string _Property1; [Column(Storage="_Property1", CanBeNull=false)] public string Property1 { get { return this._Property1; } set { if ((this._Property1 != value)) { this._Property1 = value; } } }

    Read the article

  • SQLite delete the last 25% of records in a database.

    - by Steven smethurst
    I am using a SQLite database to store values from a data logger. The data logger will eventually fills up all the available hard drive space on the computer. I'm looking for a way to remove the last 25% of the logs from the database once it reaches a certain limit. Using the following code: $ret = Query( 'SELECT id as last FROM data ORDER BY id desc LIMIT 1 ;' ); $last_id = $ret[0]['last'] ; $ret = Query( 'SELECT count( * ) as total FROM data' ); $start_id = $last_id - $ret[0]['total'] * 0.75 ; Query( 'DELETE FROM data WHERE id < '. round( $start_id, 0 ) ); A journal file gets created next to the database that fills up the remaining space on the drive until the script fails. How/Can I stop this journal file from being created? Anyway to combined all three SQL queries in to one statement?

    Read the article

  • MySQL-Cluster or Multi-Master for production? Performance issues?

    - by Phillip Oldham
    We are expanding our network of webservers on EC2 to a number of different regions and currently use master/slave replication. We've found that over the past couple of months our slave has stopped replicating a number of times which required us to clear the db and initialise the replication again. As we're now looking to have servers in 3 different regions we're a little concerned about these MySQL replication errors. We believe they're due to auto_increment values, so we're considering a number of approaches to quell these errors and stabilise replication: Multi-Master replication; 3 masters (one in each region), with the relevant auto_increment offsets, regularly backing up to S3. Or, MySQL-Cluster; 3 nodes (one in each region) with a separate management node which will also aggregate logs and statistics. After investigating it seems they both have down-sides (replication errors for the former, performance issues for the latter). We believe the cluster approach would allow us to manage and add new nodes more easily than the Multi-Master route, and would reduce/eliminate the replication issues we're currently seeing. But performance is a priority. Are the performance issues of MySQL-Cluster as bad as people say?

    Read the article

  • Disable "Do you want to change the color scheme to improve performance?" warning

    - by William Lawn Stewart
    Sometimes this dialog box will pop up (see screenshot below). Every time it appears I select "Keep the current color scheme, and don't show this message again". Windows then reminds me again -- either the next day or after reboot, or sometimes another 5 minutes later. Do you want to change the color scheme to improve performance? Windows has detected your computer's performance is slow. This could be because there are not enough resources to run the Windows Aero color scheme. To improve performance, try changing the color scheme to Windows 7 Basic. Any change you make will be in effect until the next time you log on to Windows Change the color scheme to Windows 7 Basic Keep the current color scheme, but ask me again if my computer continues to perform slowly Keep the current color scheme, and don't show this message again Is there some reason why Windows is ignoring/forgetting my attempts to suppress the dialog? I'd love to never ever see it again, it's annoying, and it alt-tabs me out of fullscreen applications. If it matters, I'm running Windows 7 x64 Professional. I believe the dialog appears because I'm forcing Vsync and Triple Buffering for DirectX applications.

    Read the article

  • At what point does the performance gap between GPU & CPU become so great that the CPU is holding back a system?

    - by Matthew Galloway
    I know that generally speaking for gaming performance the GPU is the primary factor which holds back performance, with everything else such as RAM/motherboard/PSU/CPU being secondary in importance to the graphics card. But at some point the other components ARE going to be significant in holding back the whole system! For instance nobody would be silly enough to play modern games with 512MB RAM and the very latest graphics cards (such as an HD7970) as I bet the performance increase over such a system with only 512MB but a mid range card would be non-existent! Thus it would be a "waste" for such a person to buy any high end graphics card without resolving first the system's other problems. The same point applies to other components, such as if it only had a Pentium II a current high end graphics card would be wasted on it! So my core question is how do you determine at what point for your system is spending on extra GPU power be completely "wasted"? (also, a slightly more nuanced question is trying work out at what point might the extra graphics power not be "wasted" but would be "sub optimal" value for money, when the expenditure should then be split around graphics card and other components. As obviously a gamer shouldn't always just spend on upgrading the graphics card! But needs to balance it out)

    Read the article

  • Why is my server performance degrading to the point of stopping, periodically?

    - by Pascal Aschwanden
    So, once in a while, I see in firebug that a request takes over 15 or even 60 seconds to respond and sometimes never. Here is what I've ruled out: It's not the CPU, cuz every time I check the Server load its less then 6 for all 3 numbers It's not the memory, because thats fairly low too, less the 50% It's not the I/O anymore, because I've seen the graphs that Joyent sent back to me when I requested them, and they show less then 3MB of I/O (mostly all read). It's not the SQL performance - I've profiled every last SQL command that runs, and they're all (99.9% of them anyway) running in less then 30ms, most run in less then 5ms. Oh and I've been profiling all the script execution times, and even the when the problem occurs, the script always manages to finish in 50ms or less (that's 1 / 20th of a second ). Now, I do run alot of ajax calls. 1 every 2 seconds per user and I have 300 DAU+. But, even if all 300 are playing simultaneously, thats still only 150 calls per second max. The only other thing I can think of is that one of my neighbors is funky. The problem is highly intermittent. 99% of the time it works perfectly and there's excellent performance. but 99%+ is not good enough. Eventually the performance gets so bad I have to restart the server, at which point everything is fine again. I've done this about 4 times now. Any ideas? Note: this is on joyent, vps, intro package 256mb of ram with bursting. here are the mysql dump info: Traffic ø per hour Received 18 MiB 29 MiB Sent 134 MiB 221 MiB Total 151 MiB 251 MiB Connections ø per hour % max. concurrent connections 5 --- --- Failed attempts 0 0.00 0.00% Aborted 0 0.00 0.00% Total 9,418 15.59 k 100.00%

    Read the article

  • WINDOWS: Your computer hangs. You can windows + R (run dialog) but performance is so halted taskMGR

    - by John Sullivan
    The question is, what process are available to try to recover from total system instability before pulling the plug when we can do nothing but programs or batches in the path from the run dialog (windows + r key), and performance is so dead that taskMGR / procEXP / other programs with visual guis are not usable? I am not a windows expert, but ideally someone out there has written a program that does more or less stuff like this: Immediately set (or perhaps I can set from the run prompt) its priority to extremely high, evaluate performance bottlenecks. E.g. is CPU 100%? If so identify offending program(s) or problems. Attempt / log fixes, then provide crude feedback asking the user if his performance has stabilized enough to abort, wait a few seconds, if no feedback continue, etc. etc. Eventually try to do any "system cleanup" if the program decides it cannot recover and perhaps finally provide a series of beeps to the user, or what have you, to say "OK, I give up, time to pull the plug". Ideally create a log, when able. These kinds of horrible hangs are a situation where surely trying something, anything, is better than nothing -- as long as that something is intelligent -- when the alternative is ripping out the power coord. Again, I am not a windows expert, so perhaps there is a much more elegant "hands on" approach I am not aware of.

    Read the article

  • Speaking at Triangle SQL Server User Group 16 Mar 2010!

    - by andyleonard
    I'm excited to present Applied SSIS Design Patterns to the Triangle SQL Server User Group 16 Mar 2010! This is a reprise of my PASS Summit 2009 spotlight session. If you read this blog and make the meeting, introduce yourself! :{> Andy Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!...(read more)

    Read the article

  • Presenting to the New England SQL Server Users Group 10 Jun 2010!

    - by andyleonard
    I am honored to present Applied SSIS Design Patterns to the New England SQL Server Users Group on 10 Jun 2010! This is a reprise of the spotlight session presented at the PASS Summit 2009. Abstract "Design Patterns" is more than a trendy buzz phrase; design patterns are a way of breaking down complex development projects into manageable tasks. They lend themselves to several development methodologies and apply to SSIS development. Chances are you're using your own design patterns now! In this spotlight...(read more)

    Read the article

  • Dealing with huge SQL resultset

    - by Dave McClelland
    I am working with a rather large mysql database (several million rows) with a column storing blob images. The application attempts to grab a subset of the images and runs some processing algorithms on them. The problem I'm running into is that, due to the rather large dataset that I have, the dataset that my query is returning is too large to store in memory. For the time being, I have changed the query to not return the images. While iterating over the resultset, I run another select which grabs the individual image that relates to the current record. This works, but the tens of thousands of extra queries have resulted in a performance decrease that is unacceptable. My next idea is to limit the original query to 10,000 results or so, and then keep querying over spans of 10,000 rows. This seems like the middle of the road compromise between the two approaches. I feel that there is probably a better solution that I am not aware of. Is there another way to only have portions of a gigantic resultset in memory at a time? Cheers, Dave McClelland

    Read the article

  • Which non-clustered index should I use?

    - by Junior Mayhé
    Here I am studying nonclustered indexes on SQL Server Management Studio. I've created a table with more than 1 million records. This table has a primary key. CREATE TABLE [dbo].[Customers]( [CustomerId] [int] IDENTITY(1,1) NOT NULL, [CustomerName] [varchar](100) NOT NULL, [Deleted] [bit] NOT NULL, [Active] [bit] NOT NULL, CONSTRAINT [PK_Customers] PRIMARY KEY CLUSTERED ( [CustomerId] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] This is the query I'll be using to see what execution plan is showing: SELECT CustomerName FROM Customers Well, executing this command with no additional non-clustered index, it leads the execution plan to show me: I/O cost = 3.45646 Operator cost = 4.57715 Now I'm trying to see if it's possible to improve performance, so I've created a non-clustered index for this table: 1) First non-clustered index CREATE NONCLUSTERED INDEX [IX_CustomerID_CustomerName] ON [dbo].[Customers] ( [CustomerId] ASC, [CustomerName] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] GO Executing again the select against Customers table, the execution plan shows me: I/O cost = 2.79942 Operator cost = 3.92001 It seems better. Now I've deleted this just created non-clustered index, in order to create a new one: 2) First non-clustered index CREATE NONCLUSTERED INDEX [IX_CustomerIDIncludeCustomerName] ON [dbo].[Customers] ( [CustomerId] ASC ) INCLUDE ( [CustomerName]) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] GO With this new non-clustered index, I've executed the select statement again and the execution plan shows me the same result: I/O cost = 2.79942 Operator cost = 3.92001 So, which non-clustered index should I use? Why the costs are the same on execution plan for I/O and Operator? Am I doing something wrong or this is expected? thank you

    Read the article

  • Self-referencing tables in Linq2Sql

    - by J-Man
    Hi, I've seen a lot of questions on self-referencing tables in Linq2Sql and how to eagerly load all child records for a particular root object. I've implemented a temporary solution by accessing all underlying properties, but you can see that this doesn't do the performance any good. The thing is though, that all records are correlated with each-other using a correlation GUID. Example below: RootElement - Id: 1 - ParentId: null - CorrelationId: 4D68E512-4B55-44f4-BA5A-174B630A03DD ChildElement1 - Id: 2 - ParentId: 1 - CorrelationId: 4D68E512-4B55-44f4-BA5A-174B630A03DD ChildElement2 - Id: 3 - ParentId: 2 - CorrelationId: 4D68E512-4B55-44f4-BA5A-174B630A03DD ChildElement1 - Id: 4 - ParentId: 2 - CorrelationId: 4D68E512-4B55-44f4-BA5A-174B630A03DD In my case, I do have access to the correlationId, so I can retrieve all of my records by performing the following query: from element in db.Elements where element.CorrelationId == '4D68E512-4B55-44f4-BA5A-174B630A03DD' select element; But, of course, I want these elements associated with each other by executing this query: from element in db.Elements where element.CorrelationId == '4D68E512-4B55-44f4-BA5A-174B630A03DD' && element.ParentId == null select element; My question is: is it possible to combine the results the first query as some sort of 'caching mechanism' for the query where I get the root element? Thanks for the input. J.

    Read the article

  • Very interesting problem in Compact Framework

    - by Alexander
    Hi, i have a performance problem while inserting data to sqlce.I'm reading string and making inserts to My tables.In LU_MAM table,i insert 1000 records withing 8 seconds.After Mam tables i make some inserts but my largest table is CR_MUS.When i want to insert record into CR_MUS,it takes too much time.CR_MUS has 2000 records and insert takes 35 seconds.What can be reason?I use same logic in my insert functions.Do u have any idea?I use VS 2008 sp1. Dim reader As StringReader reader = New StringReader(data) cn = New SqlCeConnection(General.ConnString) cn.Open() If myTransfer.ClearTables(cn, cmd) = True Then progress = 0 '------------------------------------------ cmd = New SqlServerCe.SqlCeCommand Dim rs As SqlCeResultSet cmd.Connection = cn cmd.CommandType = CommandType.TableDirect Dim rec As SqlCeUpdatableRecord ' name of table While reader.Peek > -1 If strerr_col = "" Then satir = reader.ReadLine() ayrac = Split(satir, "|") If ayrac(0).ToString() = "LC" Then prgsbar.Maximum = Convert.ToInt32(ayrac(1)) ElseIf ayrac(0).ToString = "PPAR" Then . If ayrac(2).ToString <> General.PMVer Then ShowWaitCursor(False) txtDurum.Text = "Wrong Version" Exit Sub End If If p_POCKET_PARAMETERS = True Then cmd.CommandText = "POCKET_PARAMETERS" txtDurum.Text = "POCKET_PARAMETERS" rs = cmd.ExecuteResultSet(ResultSetOptions.Updatable) rec = rs.CreateRecord() p_POCKET_PARAMETERS = False End If strerr_col = myVERI_AL.POCKET_PARAMETERS_I(ayrac, cmd, rs, rec) prgsbar.Value += 1 ElseIf ayrac(0).ToString() = "MAM" Then If p_LU_MAM = True Then txtDurum.Text = "LU_MAM " cmd.CommandText = "LU_MAM" rs = cmd.ExecuteResultSet(ResultSetOptions.Updatable) rec = rs.CreateRecord() p_LU_MAM = False End If strerr_col = myVERI_AL.LU_MAM_I(ayrac, cmd, rs, rec) prgsbar.Value += 1 ElseIf ayrac(0).ToString = "KMUS" Then If p_CR_MUS = True Then cmd.CommandText = "CR_MUS" txtDurum.Text = "CR_MUS" rs = cmd.ExecuteResultSet(ResultSetOptions.Updatable) rec = rs.CreateRecord() p_TR_KAMPANYA_MALZEME = False End If strerr_col = myVERI_AL.CR_MUS_I(ayrac, cmd, rs, rec) prgsbar.Value += 1 end while Public Function CR_KAMPANYA_MUSTERI_I(ByVal f_Line() As String, ByRef myComm As SqlCeCommand, ByRef rs As SqlCeResultSet, ByRef rec As SqlCeUpdatableRecord) As String Try rec.SetValue(0, If(f_Line(1) = String.Empty, DirectCast(DBNull.Value, Object), f_Line(1))) rec.SetValue(1, If(f_Line(2) = String.Empty, DirectCast(DBNull.Value, Object), f_Line(2))) rec.SetValue(2, If(f_Line(3) = String.Empty, DirectCast(DBNull.Value, Object), f_Line(3))) rec.SetValue(3, If(f_Line(5) = String.Empty, DirectCast(DBNull.Value, Object), f_Line(5))) rec.SetValue(4, If(f_Line(6) = String.Empty, DirectCast(DBNull.Value, Object), f_Line(6))) rs.Insert(rec) Catch ex As Exception strerr_col = ex.Message End Try Return strerr_col End Function

    Read the article

  • Can a large transaction log cause cpu hikes to occur

    - by Simon Rigby
    Hello all, I have a client with a very large database on Sql Server 2005. The total space allocated to the db is 15Gb with roughly 5Gb to the db and 10 Gb to the transaction log. Just recently a web application that is connecting to that db is timing out. I have traced the actions on the web page and examined the queries that execute whilst these web operation are performed. There is nothing untoward in the execution plan. The query itself used multiple joins but completes very quickly. However, the db server's CPU hikes to 100% for a few seconds. The issue occurs when several simultaneous users are working on the system (when I say multiple .. read about 5). Under this timeouts start to occur. I suppose my question is, can a large transaction log cause issues with CPU performance? There is about 12Gb of free space on the disk currently. The configuration is a little out of my hands but the db and log are both on the same physical disk. I appreciate that the log file is massive and needs attending to, but I'm just looking for a heads up as to whether this may cause CPU spikes (ie trying to find the correlation). The timeouts are a recent thing and this app has been responsive for a few years (ie its a recent manifestation). Many Thanks,

    Read the article

  • Help on understanding multiple columns on an index?

    - by Xaisoft
    Assume I have a table called "table" and I have 3 columns, a, b, and c. What does it mean to have a non-clustered index on columns a,b? Is a nonclustered index on columns a,b the same as a nonclustered index on columns b,a? (Note the order). Also, Is a nonclustered index on column a the same as a nonclustered index on a,c? I was looking at the website sqlserver performance and they had these dmv scripts where it would tell you if you had overlapping indexes and I believe it was saying that having an index on a is the same as a,b, so it is redundant. Is this true about indexes? One last question is why is the clustered index put on the primary key. Most of the time the primary key is not queried against, so shouldn't the clustered index be on the most queried column. I am probably missing something here like having it on the primary key speeds up joins? Great explanations. Should I turn this into a wiki and change the title index explanation?

    Read the article

  • JSON VIEW using GROUP_CONCAT question

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

    Read the article

  • Complex LINQ paging algorithm

    - by sharepointmonkey
    We have a list of projects that may or may not have a collection of subprojects. Our report needs to contain all the projects except those that are the parent project of a subproject. I need to page this into pages of, say, 25 rows. But if subprojects appear on that page then ALL the subprojects of that project must appear on the same page. So more than 25 items may appear if necessary. I've got as far as var pagedProjects = db.Projects.Where(x => !x.SubProjects.Any()).Skip( (pageNo -1) * pageSize).Take(pageSize); Obviously, this fails the second part of the requirements. As a further pain in the arse, I need to have a pager control on the report. So I'll need to be able to calculate the total number of pages. I could loop through the whole table of projects but the performance will suffer. Can anybody come up with a paged solution? EDIT - I should probably mention that SubProjects joins back onto Projects via a selfreferencing foreign key so the whole lot comes back as an IQueryable<Project>.

    Read the article

  • PostgreSQL, Foreign Keys, Insert speed & Django

    - by Miles
    A few days ago, I ran into an unexpected performance problem with a pretty standard Django setup. For an upcoming feature, we have to regenerate a table hourly, containing about 100k rows of data, 9M on the disk, 10M indexes according to pgAdmin. The problem is that inserting them by whatever method literally takes ages, up to 3 minutes of 100% disk busy time. That's not something you want on a production site. It doesn't matter if the inserts were in a transaction, issued via plain insert, multi-row insert, COPY FROM or even INSERT INTO t1 SELECT * FROM t2. After noticing this isn't Django's fault, I followed a trial and error route, and hey, the problem disappeared after dropping all foreign keys! Instead of 3 minutes, the INSERT INTO SELECT FROM took less than a second to execute, which isn't too surprising for a table <= 20M on the disk. What is weird is that PostgreSQL manages to slow down inserts by 180x just by using 3 foreign keys. Oh, disk activity was pure writing, as everything is cached in RAM; only writes go to the disks. It looks like PostgreSQL is working very hard to touch every row in the referred tables, as 3MB/sec * 180s is way more data than the 20MB this new table takes on disk. No WAL for the 180s case, I was testing in psql directly, in Django, add ~50% overhead for WAL logging. Tried @commit_on_success, same slowness, I had even implemented multi row insert and COPY FROM with psycopg2. That's another weird thing, how can 10M worth of inserts generate 10x 16M log segments? Table layout: id serial primary, a bunch of int32, 3 foreign keys to small table, 198 rows, 16k on disk large table, 1.2M rows, 59 data + 89 index MB on disk large table, 2.2M rows, 198 + 210MB So, am I doomed to either drop the foreign keys manually or use the table in a very un-Django way by defining saving bla_id x3 and skip using models.ForeignKey? I'd love to hear about some magical antidote / pg setting to fix this.

    Read the article

  • how to design a schema where the columns of a table are not fixed

    - by hIpPy
    I am trying to design a schema where the columns of a table are not fixed. Ex: I have an Employee table where the columns of the table are not fixed and vary (attributes of Employee are not fixed and vary). Nullable columns in the Employee table itself i.e. no normalization Instead of adding nullable columns, separate those columns out in their individual tables ex: if Address is a column to be added then create table Address[EmployeeId, AddressValue]. Create tables ExtensionColumnName [EmployeeId, ColumnName] and ExtensionColumnValue [EmployeeId, ColumnValue]. ExtensionColumnName would have ColumnName as "Address" and ExtensionColumnValue would have ColumnValue as address value. Employee table EmployeeId Name ExtensionColumnName table ColumnNameId EmployeeId ColumnName ExtensionColumnValue table EmployeeId ColumnNameId ColumnValue There is a drawback is the first two ways as the schema changes with every new attribute. Note that adding a new attribute is frequent. I am not sure if this is the good or bad design. If someone had a similar decision to make, please give an insight on things like foreign keys / data integrity, indexing, performance, reporting etc.

    Read the article

  • How can I optimize the SELECT statement running on an Oracle database?

    - by Elvis Lou
    I have a SELECT statement in ORACLE: SELECT COUNT(DISTINCT ds1.endpoint_msisdn) multiple30, dss1.service, dss1.endpoint_provisioning_id, dss1.company_scope, Nvl(x.subscription_status, dss1.subscription_status) subscription_status FROM daily_summary ds1 join daily_summary ds2 ON ds1.endpoint_msisdn = ds2.endpoint_msisdn, daily_summary_static dss1, daily_summary_static dss2, (SELECT NULL subscription_status FROM dual UNION ALL SELECT -2 subscription_status FROM dual) x WHERE ds1.summary_ts >= To_date('10-04-2012', 'dd-mm-yyyy') - 30 AND ds1.summary_ts <= To_date('10-04-2012', 'dd-mm-yyyy') AND dss1.last_active >= To_date('10-04-2012', 'dd-mm-yyyy') - 30 AND dss1.last_active <= To_date('10-04-2012', 'dd-mm-yyyy') AND dss2.last_active >= To_date('10-04-2012', 'dd-mm-yyyy') - 30 AND dss2.last_active <= To_date('10-04-2012', 'dd-mm-yyyy') AND dss1.service <> dss2.service AND ( dss1.company_scope = 2 OR dss1.company_scope = 5 ) AND ( dss2.company_scope = 2 OR dss2.company_scope = 5 ) AND dss1.company_scope = dss2.company_scope AND ds1.endpoint_noc_id = dss1.endpoint_noc_id AND ds1.endpoint_host_id = dss1.endpoint_host_id AND ds1.endpoint_instance_id = dss1.endpoint_instance_id AND ds2.endpoint_noc_id = dss2.endpoint_noc_id AND ds2.endpoint_host_id = dss2.endpoint_host_id AND ds2.endpoint_instance_id = dss2.endpoint_instance_id AND dss1.endpoint_provisioning_id = dss2.endpoint_provisioning_id AND Least(1, ds1.total_actions) = 1 AND Least(1, ds2.total_actions) = 1 GROUP BY dss1.service, dss1.endpoint_provisioning_id, dss1.company_scope, Nvl(x.subscription_status, dss1.subscription_status); This query took about 26 minutes to return in my environment, but if I remove the section: dss1.last_active >= to_date('10-04-2012','dd-mm-yyyy') - 30 AND dss1.last_active <= to_date('10-04-2012','dd-mm-yyyy') AND dss2.last_active >= to_date('10-04-2012','dd-mm-yyyy') - 30 AND dss2.last_active <= to_date('10-04-2012','dd-mm-yyyy') AND it only took 20 seconds to run. We have index on the column last_active, I don't know why the section slow down the performance so much? any ideas?

    Read the article

  • MySQL Database Design with Internationalization

    - by Some name
    Hello, I'm going to start work on a medium sized application, and i'm planning it's db design. One thing that I'm not sure about is this. I will have many tables which will need internationalization, such as: "membership_options, gender_options, language_options etc" Each of these tables will share common i18n fields, like: "title, alternative_title, short_description, description" In your opinion which is the best way to do it? Have an i18n table with the same fields for each of the tables that will need them? or do something like: Membership table Gender table ---------------- -------------- id | created_at id | created_at 1 - 22.03.2001 1 - 14.08.2002 2 - 22.03.2001 2 - 14.08.2002 General translation table ------------------------- record_id | table_name | string_name | alternative_title| .... |id_language 1 - membership regular null 1 (english) 1 - membership normale null 2 (italian) 1 - gender man null 1(english) 1 -gender uomo null 2(italian) This would avoid me repeating something like: membership_translation table ----------------------------- membership_id | name | alternative_title | id_lang 1 regular null 1 1 normale null 2 gender_translation table ----------------------------- gender_id | name | alternative_title | id_lang 1 man null 1 1 uomo null 2 and so on, so i would probably reduce the number of db tables, but i'm not sure about performance.I'm not much of a DB designer, so please let me know.

    Read the article

  • Why are my connections not closed even if I explicitly dispose of the DataContext?

    - by Chris Simpson
    I encapsulate my linq to sql calls in a repository class which is instantiated in the constructor of my overloaded controller. The constructor of my repository class creates the data context so that for the life of the page load, only one data context is used. In my destructor of the repository class I explicitly call the dispose of the DataContext though I do not believe this is necessary. Using performance monitor, if I watch my User Connections count and repeatedly load a page, the number increases once per page load. Connections do not get closed or reused (for about 20 minutes). I tried putting Pooling=false in my config to see if this had any effect but it did not. In any case with pooling I wouldn't expect a new connection for every load, I would expect it to reuse connections. I've tried putting a break point in the destructor to make sure the dispose is being hit and sure enough it is. So what's happening? Some code to illustrate what I said above: The controller: public class MyController : Controller { protected MyRepository rep; public MyController () { rep = new MyRepository(); } } The repository: public class MyRepository { protected MyDataContext dc; public MyRepository() { dc = getDC(); } ~MyRepository() { if (dc != null) { //if (dc.Connection.State != System.Data.ConnectionState.Closed) //{ // dc.Connection.Close(); //} dc.Dispose(); } } // etc } Note: I add a number of hints and context information to the DC for auditing purposes. This is essentially why I want one connection per page load

    Read the article

< Previous Page | 699 700 701 702 703 704 705 706 707 708 709 710  | Next Page >