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  • MySQL Connect 9 Days Away – Optimizer Sessions

    - by Bertrand Matthelié
    72 1024x768 Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Following my previous blog post focusing on InnoDB talks at MySQL Connect, let us review today the sessions focusing on the MySQL Optimizer: Saturday, 11.30 am, Room Golden Gate 6: MySQL Optimizer Overview—Olav Sanstå, Oracle The goal of MySQL optimizer is to take a SQL query as input and produce an optimal execution plan for the query. This session presents an overview of the main phases of the MySQL optimizer and the primary optimizations done to the query. These optimizations are based on a combination of logical transformations and cost-based decisions. Examples of optimization strategies the presentation covers are the main query transformations, the join optimizer, the data access selection strategies, and the range optimizer. For the cost-based optimizations, an overview of the cost model and the data used for doing the cost estimations is included. Saturday, 1.00 pm, Room Golden Gate 6: Overview of New Optimizer Features in MySQL 5.6—Manyi Lu, Oracle Many optimizer features have been added into MySQL 5.6. This session provides an introduction to these great features. Multirange read, index condition pushdown, and batched key access will yield huge performance improvements on large data volumes. Structured explain, explain for update/delete/insert, and optimizer tracing will help users analyze and speed up queries. And last but not least, the session covers subquery optimizations in Release 5.6. Saturday, 7.00 pm, Room Golden Gate 4: BoF: Query Optimizations: What Is New and What Is Coming? This BoF presents common techniques for query optimization, covers what is new in MySQL 5.6, and provides a discussion forum in which attendees can tell the MySQL optimizer team which optimizations they would like to see in the future. Sunday, 1.15 pm, Room Golden Gate 8: Query Performance Comparison of MySQL 5.5 and MySQL 5.6—Øystein Grøvlen, Oracle MySQL Release 5.6 contains several improvements in the query optimizer that create improved performance for complex queries. This presentation looks at how MySQL 5.6 improves the performance of many of the queries in the DBT-3 benchmark. Based on the observed improvements, the presentation discusses what makes the specific queries perform better in Release 5.6. It describes the relevant new optimization techniques and gives examples of the types of queries that will benefit from these techniques. Sunday, 4.15 pm, Room Golden Gate 4: Powerful EXPLAIN in MySQL 5.6—Evgeny Potemkin, Oracle The EXPLAIN command of MySQL has long been a very useful tool for understanding how MySQL will execute a query. Release 5.6 of the MySQL database offers several new additions that give more-detailed information about the query plan and make it easier to understand at the same time. This presentation gives an overview of new EXPLAIN features: structured EXPLAIN in JSON format, EXPLAIN for INSERT/UPDATE/DELETE, and optimizer tracing. Examples in the session give insights into how you can take advantage of the new features. They show how these features supplement and relate to each other and to classical EXPLAIN and how and why the MySQL server chooses a particular query plan. You can check out the full program here as well as in the September edition of the MySQL newsletter. Not registered yet? You can still save US$ 300 over the on-site fee – Register Now!

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  • How to use opencv header in visual studio windows app

    - by yooo
    I did my work in visual studio 2010 c++ console , but now i am trying to convert my work into windows app (making interface of it) in visual studio c++ . For that i have to add some header files which i have to add manually in windows form application, like and it show me some error's in it like DetectRegions.h(10): error C2146: syntax error : missing ';' before identifier 'filename' DetectRegions.h(10): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int DetectRegions.h(10): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int DetectRegions.h(11): error C2061: syntax error : identifier 'string' DetectRegions.h(14): error C2143: syntax error : missing ';' before '<' DetectRegions.h(14): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int DetectRegions.h(14): error C2238: unexpected token(s) preceding ';' DetectRegions.h(16): error C2143: syntax error : missing ';' before '<' DetectRegions.h(16): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int DetectRegions.h(16): error C2238: unexpected token(s) preceding ';' DetectRegions.h(17): error C2061: syntax error : identifier 'RotatedRect' DetectRegions.h(18): error C2653: 'cv' : is not a class or namespace name DetectRegions.h(18): error C2146: syntax error : missing ';' before identifier 'histeq' DetectRegions.h(18): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int DetectRegions.h(18): error C2061: syntax error : identifier 'Mat' DetectRegions.h(18): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int DetectRegions.h(18): warning C4183: 'histeq': missing return type; assumed to be a member function returning 'int' Plate.h is same like DetectRegions.h I add the other headers of opencv in Form1.h like #include "opencv2/features2d/features2d.hpp" #include <opencv/highgui.h> #include "opencv2/opencv.hpp" .......

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  • Namespace Problem

    - by Tarik
    Hello, Normally we all do use using System.Linq; and using System.Data.Linq; for example on the code-behind and expect we can reach the members of these namespaces from Source Code like <%= Something.First()%> but when I wrote it, asp.net said it couldn't find First() in the context and I had to add <%@ Import Namespace="System.Linq" which looked very weird to me but it worked out. Since they are targeting at the same class why they both need separate namespace importing. Code-behind : using System; using System.Data.Linq; using System.Linq; using System.Text namespace Something { class Items : System.Web.UI { //... } } but also I need to add the same Linq namespace on the Html Source part <%@Import Namespace="System.Linq"%> Do I know something wrong or this is some kind of bug in asp.net. I thought when the page is compiling, asp.net combines these two classes and converts html source code into cs class and indicates the control in Control c= new Control(); hierarchy. Thanks in advance.

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  • Asp.Net Random Error

    - by John Boker
    At random times, twice in the past two weeks, the we application will start to error and not work until I recycle the app pool in IIS. The specific error and stacktrace are: System.Web.HttpUnhandledException: Exception of type 'System.Web.HttpUnhandledException' was thrown. ---> System.InvalidCastException: Unable to cast object of type 'System.Guid' to type 'System.String'. at System.Data.Linq.SqlClient.SqlProvider.Execute(Expression query, QueryInfo queryInfo, IObjectReaderFactory factory, Object[] parentArgs, Object[] userArgs, ICompiledSubQuery[] subQueries, Object lastResult) at System.Data.Linq.SqlClient.SqlProvider.ExecuteAll(Expression query, QueryInfo[] queryInfos, IObjectReaderFactory factory, Object[] userArguments, ICompiledSubQuery[] subQueries) at System.Data.Linq.SqlClient.SqlProvider.System.Data.Linq.Provider.IProvider.Execute(Expression query) at System.Data.Linq.DataQuery`1.System.Linq.IQueryProvider.Execute[S](Expression expression) at System.Linq.Queryable.FirstOrDefault[TSource](IQueryable`1 source) at DigitalScout.WEDS.Business.Slug.GetTeamPath(String teamID) at DigitalScout.WEDS.WebApp.Code.Navigator.TeamNavigator.Home(String teamID) at ASP.management_default_aspx.__DataBind__control7(Object sender, EventArgs e) at System.Web.UI.Control.OnDataBinding(EventArgs e) at System.Web.UI.Control.DataBind(Boolean raiseOnDataBinding) at System.Web.UI.Control.DataBindChildren() at System.Web.UI.Control.DataBind(Boolean raiseOnDataBinding) at System.Web.UI.WebControls.Repeater.CreateControlHierarchy(Boolean useDataSource) at System.Web.UI.WebControls.Repeater.OnDataBinding(EventArgs e) at System.Web.UI.Control.DataBindChildren() at System.Web.UI.Control.DataBind(Boolean raiseOnDataBinding) at System.Web.UI.WebControls.Repeater.CreateControlHierarchy(Boolean useDataSource) at System.Web.UI.WebControls.Repeater.OnDataBinding(EventArgs e) at DigitalScout.WEDS.WebApp.Management._default.Page_Load(Object sender, EventArgs e) at System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) at System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) at System.Web.UI.Control.OnLoad(EventArgs e) at DigitalScout.WEDS.WebApp.Code.BaseClass.Pages.ManagementPage.OnLoad(EventArgs e) at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) --- End of inner exception stack trace --- at System.Web.UI.Page.HandleError(Exception e) at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) at System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) at System.Web.UI.Page.ProcessRequest() at System.Web.UI.Page.ProcessRequest(HttpContext context) at ASP.management_default_aspx.ProcessRequest(HttpContext context) at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) This error happens for every user of the system until the app pool is recycled. Any help on this would be helpful as we are not able to reproduce the error.

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  • Problem showing selected value of combobox when it is bind to a List<T> using Linq to Entities

    - by Syed Mustehsan Ikram
    I have a combobox which is has itemtemplate applied on it and is bind to a List of entity return using linq. i m using mvvm. It is bind to it successfully but when i set the selected value of it from code at runtime to show the selected value coming from db it doesn't select it. For reference here is my combobox xaml. SelectedValue="{Binding Path=SelectedManufacturer}" Grid.Column="3" Grid.Row="2" Margin="20,9.25,68,7.75" ItemTemplate="{StaticResource ManufacturerDataTemplate}" TabIndex="6"/ Here is my part from code behind from viewModel. List currentManufacturers = new List(); tblManufacturer selectedManufacturer = null; public List CurrentManufacturers { get { return currentManufacturers; } set { currentManufacturers = value; NotifyPropertyChanged("CurrentManufacturers"); } } public tblManufacturer SelectedManufacturer { get { return selectedManufacturer; } set { selectedManufacturer = currentManufacturers.Where(mm => mm.ManufacturerID == Convert.ToInt32(selectedDevice.tblManufacturer.EntityKey.EntityKeyValues[0].Value)).First(); NotifyPropertyChanged("SelectedManufacturer"); } }

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  • Cygwin vim doesn't load files in runtimepath

    - by durron597
    I created a custom syntax file, and but none of the files in $VIMRUNTIME seem to load. I followed these pieces of the documentation: http://vimdoc.sourceforge.net/htmldoc/filetype.html#new-filetype http://vimdoc.sourceforge.net/htmldoc/syntax.html#mysyntaxfile When I do :echo &runtimepath I get: /home/durron597/.vim,/usr/share/vim/vimfiles,/usr/share/vim/vim73,/usr/share/vim/vimfiles/after,/home/durron597/.vim/after However, if I open a file with vim -D, here's the listed files as I type f: /etc/vimrc /home/durron597/.vimrc /usr/share/vim/vim73/plugin/getscriptPlugin.vim /usr/share/vim/vim73/plugin/gzip.vim /usr/share/vim/vim73/plugin/matchparen.vim /usr/share/vim/vim73/plugin/netrwPlugin.vim /usr/share/vim/vim73/plugin/rrhelper.vim /usr/share/vim/vim73/plugin/spellfile.vim /usr/share/vim/vim73/plugin/tarPlugin.vim /usr/share/vim/vim73/plugin/tohtml.vim /usr/share/vim/vim73/plugin/vimballPlugin.vim /usr/share/vim/vim73/plugin/zipPlugin.vim Here's the output of ls -lR durron597@Durron597 ~/.vim $ ls -lR .: total 0 drwxr-xr-x+ 1 durron597 None 0 Jun 3 11:06 ftdetect drwxr-xr-x+ 1 durron597 None 0 Jun 3 11:06 syntax ./ftdetect: total 1.0K -rw-r--r-- 1 durron597 None 45 Jun 3 11:06 mytype.vim ./syntax: total 4.0K -rw-r--r-- 1 durron597 None 740 Jun 3 11:06 mytype.vim The exact exact paths are: /home/durron597/.vim/ftdetect/mytype.vim /home/durron597/.vim/syntax/mytype.vim Note: the problem is that these files don't seem to be loaded at all, not that these files have internal mistakes Output of :filetype filetype detection:ON plugin:ON indent:OFF Edit 3: No, really, the files are in the right place: $ find /home -name '*.vim' /home/durron597/.vim /home/durron597/.vim/ftdetect/fix.vim /home/durron597/.vim/syntax/fix.vim

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  • Hibernate: Perform criteria query with Sub-Select AND Left-Outer join?

    - by Markos Fragkakis
    Can I perform a Criteria query with Sub-Select AND Left-Outer join? For example, I have A 1-many B 1-many C. With Criteria.createAlias ("b", "b", Criteria.LEFT_JOIN) I can perform Left Outer join. With Criteria.setFetchMode ("b", org.hibernate.FetchMode.DEFAULT) I can perform Join with the default fetching strategy. I assume that having set @org.hibernate.annotations.FetchMode.SUBSELECT in both A.B and B.C is enough (is it?). Question 1: Why does org.hibernate.FetchMode not have SUBSELECT option, whereas the org.hibernate.annotations.FetchMode does? Question 2: Can I perform a Criteria query with Sub-Select AND Left-Outer join?

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  • Silverlight RIA Services. Query fails on large table but works with Where clause

    - by FauxReal
    I have a somewhat large table, maybe 2000 rows by 50 columns. When using the most basic imaginable RIA implementation. Create one-table Model Create DomainService Drop datagrid onto MainPage.xaml Drop datasource onto datagrid Ctrl-F5 I get this error: System.ServiceModel.DomainServices.Client.DomainOperationException: Load operation faild for query. Value cannot be null. Error is much larger, but thats the beginning of it. The weird thing is that if I narrow the results down with a where clause on the GetQuery, it works fine. In fact six different querys which together result in all of the rows being called works fine also. So basically, I'm sure its not some sort of rogue row. Why do I get this "Value cannot be null" error if I query the whole table? Thanks

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  • (Oracle Performance) Will a query based on a view limit the view using the where clause?

    - by BestPractices
    In Oracle (10g), when I use a View (not Materialized View), does Oracle take into account the where clause when it executes the view? Let's say I have: MY_VIEW = SELECT * FROM PERSON P, ORDERS O WHERE P.P_ID = O.P_ID And I then execute the following: SELECT * FROM MY_VIEW WHERE MY_VIEW.P_ID = '1234' When this executes, does oracle first execute the query for the view and THEN filter it based on my where clause (where MY_VIEW.P_ID = '1234') or does it do this filtering as part of the execution of the view? If it does not do the latter, and P_ID had an index, would I also lose out on the indexing capability since Oracle would be executing my query against the view which doesn't have the index rather than the base table which has the index?

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  • Is this sufficient to prevent query injection while using SQL Server?

    - by Derek Adair
    Hi, I have recently taken on a project in which I need to integrate with PHP/SQL Server. I am looking for the quickest and easiest function to prevent SQL injection on SQL Server as I prefer MySQL and do not anticipate many more SQL Server related projects. Is this function sufficient? $someVal = mssql_escape($_POST['someVal']); $query = "INSERT INTO tblName SET field = $someVal"; mssql_execute($query); function mssql_escape($str) { return str_replace("'", "''", $str); } If not, what additional steps should I take?

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  • SQL 05 full-text query fails "Specified module could not be found."

    - by Dan Bailiff
    I'm running SQL 2005 on Windows XP. I have a database table that has full text searching enabled. I was able to build and even re-build the index. However, when I try to query it like this: Select * from fulltext_english WHERE CONTAINS(page_data, 'causes') I get this error: Msg 7619, Level 16, State 1, Line 1 The execution of a full-text query failed. "The specified module could not be found." Did I miss something on the install? Is this a dll issue? I've googled and binged for days and can't find anything similar to this message. Thanks!

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  • Is it more efficient to always run a delete query, or to check if that information exists first

    - by Scarface
    Ok this is going to seem like a dumb question to experienced developers, but questions like this bother me until I ask them. So... is it more efficient to always run a delete query by default whether an entry exists or not, for example to delete a user name after a certain period of time (DELETE * from table where username=user), or should you check if that entry exists first using a select query and mysql_num_rows. What uses more processor on the server side? Obviously one approach contains more code, but I was wondering if certain mysql operations used a lot more cpu than others.

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  • How to salvage SQL server 2008 query from KILLED/ROLLBACK state?

    - by littlegreen
    I have a stored procedure that inserts batches of millions of rows, emerging from a certain query, into an SQL database. It has one parameter selecting the batch; when this parameter is omitted, it will gather a list of batches and recursively call itself, in order to iterate over batches. In (pseudo-)code, it looks something like this: CREATE PROCEDURE spProcedure AS BEGIN IF @code = 0 BEGIN ... WHILE @@Fetch_Status=0 BEGIN EXEC spProcedure @code FETCH NEXT ... INTO @code END END ELSE BEGIN -- Disable indexes ... INSERT INTO table SELECT (...) -- Enable indexes ... Now it can happen that this procedure is slow, for whatever reason: it can't get a lock, one of the indexes it uses is misdefined or disabled. In that case, I want to be able kill the procedure, truncate and recreate the resulting table, and try again. However, when I try and kill the procedure, the process frequently oozes into a KILLED/ROLLBACK state from which there seems to be no return. From Google I have learned to do an sp_lock, find the spid, and then kill it with KILL <spid>. But when I try to kill it, it tells me SPID 75: transaction rollback in progress. Estimated rollback completion: 0%. Estimated time remaining: 554 seconds. I did find a forum message hinting that another spid should be killed before the other one can start a rollback. But that didn't work for me either, plus I do not understand, why that would be the case... could it be because I am recursively calling my own stored procedure? (But it should be having the same spid, right?) In any case, my process is just sitting there, being dead, not responding to kills, and locking the table. This is very frustrating, as I want to go on developing my queries, not waiting hours on my server sitting dead while pretending to be finishing a supposed rollback. Is there some way in which I can tell the server not to store any rollback information for my query? Or not to allow any other queries to interfere with the rollback, so that it will not take so long? Or how to rewrite my query in a better way, or how kill the process successfully without restarting the server?

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  • How to get entries from the second level query cache ?

    - by fabien7474
    In my grails application, I want to display all the current entries of the second-level cache from all regions. My code is as following : def getCacheStats() { StatisticsImpl stats = sessionFactory.statistics for (regionName in stats.secondLevelCacheRegionNames) { log.debug stats.getSecondLevelCacheStatistics(regionName).entries } } However everything works fine as long as the region name is not org.hibernate.cache.StandardQueryCache (region used for Query Cache). In that case, an exception is thrown : java.lang.ClassCastException: org.hibernate.cache.QueryKey cannot be cast to org.hibernate.cache.CacheKey Having googling around, I didn't find any clues about how to display the list of entries of the cached query result sets associated with regions StandardQueryCache and UpdateTimestampsCache. Could you please help me find a solution for this?

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  • How can i query for null values in entity framework?

    - by AZ
    I want to execute a query like this var result = from entry in table where entry.something == null select entry; and get an IS NULL generated. Edited: After the first two answers i feel the need to clarify that I'm using Entity Framework and not Linq to SQL. The object.Equals() method does not seem to work in EF. Edit no.2: The above query works as intended. It correctly generates IS NULL. My production code however was var value = null; var result = from entry in table where entry.something == value select entry; and the generated SQL was something = @p; @p = NULL. It seems that EF correctly translates the constant expression but if a variable is involved it treats it just like a normal comparison. Makes sense actually. I'll close this question

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  • MYSQL query to get all entries with specific time, from PHP?

    - by meds
    I'm trying to query a mysql table which places its date in the following format: yyyy-mm-dd hh:mm:ss So it's date and time, and that's all in a single field. Now from php I want to get the time and query the table to only return entries where the date field is less than 24 hours old. I'm having issues with the system because PHPs get time seems to return the values seperately and I'm struggling to figure out how to make it work with mysql queries. This seems fairly simple but I'm quite new to php so sorry if I'm completely missing something..

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  • Is there any way to simplify a verbose SQL INSERT INTO(..) query?

    - by Soundar Rajan
    I have a table with one id (autonumber) field and 50 other fields. The table is normalized, these are 50 material properties etc. I want to copy a record from this table into the same table - only the autoincrement id will be different. The query I am using now is INSERT INTO tableName (field1,field2,....field50) SELECT field1,field2,....field50 from tableName WHERE autoid=1234; Note that I have to type in ALL the 50 field names, twice! Is there any way to shorten this query so I don't have to type all of them? Thanks.

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  • Mysql: i need to get the offset of a item in a query.

    - by user305270
    Mysql: i need to get the offset of a item in a query. I have a image gallery: this show 6 image per stack, so when i request image 22 it shows images from 18 to 24. It should first get the offset of the image 22, then get the images from 18 to 24. Another example: i request the image number 62(and offset 62), it will select images with offset from 60 to 66. Is possible with a single query? Thanks ;)

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  • Help need to with MySQL query to join data spanning multiple tables and use data as column names

    - by gurun8
    I need a little help putting together a SQL query that will give me the following resultsets: and The data model looks like this: The tricky part for me is that the columns to the right of the "Product" in the resultset aren't really columns in the database but rather key/value pairs spanned across the data model. Table data is as follows: My apologies in advance for the image heavy question and the image quality. This just seemed like the easiest way to convey the information. It'll probably take someone less time to write the query statement to achieve the results than it did for me to assemble this question. By the way, the "product_option" table image is truncated but it illustrated the general idea of the data structure. The MySQL server version is 5.1.45.

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  • STOP ERASING MY QUESTIONS! - VIEWING FIRST_ROWS BEFORE QUERY COMPLETES (RE-VISITED)

    - by Frank Developer
    OK, so say I have a table with 500K rows, then I ad-hoc query with unsupported indexing which requires a full table scan. I would like to immediately view the first rows returned while the full table scan continues. Then I want to scroll thru the next results. In the meantime, I would like to display the progress of the table scan, example: "SEARCHING.. FOUND 23 OF 500,000 ROWS SO FAR". If I scroll too far ahead, I want to display a message like: "REACHED LAST ROW IN LOOK-AHEAD BUFFER.. QUERY HAS NOT COMPLETED".. Can this be done? Maybe like: spawn/exec, declare scroll cursor, open, fetch, etc.?

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  • Help needed with MySQL query to join data spanning multiple tables with data used as column names

    - by gurun8
    I need a little help putting together a SQL query that will give me the following resultsets: and The data model looks like this: The tricky part for me is that the columns to the right of the "Product" in the resultset aren't really columns in the database but rather key/value pairs spanned across the data model. Table data is as follows: My apologies in advance for the image heavy question and the image quality. This just seemed like the easiest way to convey the information. It'll probably take someone less time to write the query statement to achieve the results than it did for me to assemble this question. By the way, the "product_option" table image is truncated but it illustrated the general idea of the data structure. The MySQL server version is 5.1.45.

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  • Is it OK to open a DB4o file for query, insert, update multiple times?

    - by Khnle
    This is the way I am thinking of using DB4o. When I need to query, I would open the file, read and close: using (IObjectContainer db = Db4oFactory.OpenFile(Db4oFactory.NewConfiguration(), YapFileName)) { try { List<Pilot> pilots = db.Query<Pilot>().ToList<Pilot>(); } finally { try { db.Close(); } catch (Exception) { }; } } At some later time, when I need to insert, then using (IObjectContainer db = Db4oFactory.OpenFile(Db4oFactory.NewConfiguration(), YapFileName)) { try { Pilot pilot1 = new Pilot("Michael Schumacher", 100); db.Store(pilot1); } finally { try { db.Close(); } catch (Exception) { }; } } In this way, I thought I will keep the file more tidy by only having it open when needed, and have it closed most of the time. But I keep getting InvalidCastException Unable to cast object of type 'Db4objects.Db4o.Reflect.Generic.GenericObject' to type 'Pilot' What's the correct way to use DB4o?

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