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  • Are batch mutations atomic in Cassandra?

    - by user317459
    The Cassandra API supports batch mutations: batch_mutate(keyspace, mutation_map, consistency_level): Executes the specified mutations on the keyspace. mutation_map is a map; the outer map maps the key to the inner map, which maps the column family to the Mutation; can be read as: map. To be more specific, the outer map key is a row key, the inner map key is the column family name. A Mutation specifies either columns to insert or columns to delete. See Mutation and Deletion above for more details. Are all mutations that are executed in a batch executed atomically? So if one of the mutations fails, do the others fail too?

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  • Can MySQL reasonably perform queries on billions of rows?

    - by haxney
    I am planning on storing scans from a mass spectrometer in a MySQL database and would like to know whether storing and analyzing this amount of data is remotely feasible. I know performance varies wildly depending on the environment, but I'm looking for the rough order of magnitude: will queries take 5 days or 5 milliseconds? Input format Each input file contains a single run of the spectrometer; each run is comprised of a set of scans, and each scan has an ordered array of datapoints. There is a bit of metadata, but the majority of the file is comprised of arrays 32- or 64-bit ints or floats. Host system |----------------+-------------------------------| | OS | Windows 2008 64-bit | | MySQL version | 5.5.24 (x86_64) | | CPU | 2x Xeon E5420 (8 cores total) | | RAM | 8GB | | SSD filesystem | 500 GiB | | HDD RAID | 12 TiB | |----------------+-------------------------------| There are some other services running on the server using negligible processor time. File statistics |------------------+--------------| | number of files | ~16,000 | | total size | 1.3 TiB | | min size | 0 bytes | | max size | 12 GiB | | mean | 800 MiB | | median | 500 MiB | | total datapoints | ~200 billion | |------------------+--------------| The total number of datapoints is a very rough estimate. Proposed schema I'm planning on doing things "right" (i.e. normalizing the data like crazy) and so would have a runs table, a spectra table with a foreign key to runs, and a datapoints table with a foreign key to spectra. The 200 Billion datapoint question I am going to be analyzing across multiple spectra and possibly even multiple runs, resulting in queries which could touch millions of rows. Assuming I index everything properly (which is a topic for another question) and am not trying to shuffle hundreds of MiB across the network, is it remotely plausible for MySQL to handle this? UPDATE: additional info The scan data will be coming from files in the XML-based mzML format. The meat of this format is in the <binaryDataArrayList> elements where the data is stored. Each scan produces = 2 <binaryDataArray> elements which, taken together, form a 2-dimensional (or more) array of the form [[123.456, 234.567, ...], ...]. These data are write-once, so update performance and transaction safety are not concerns. My naïve plan for a database schema is: runs table | column name | type | |-------------+-------------| | id | PRIMARY KEY | | start_time | TIMESTAMP | | name | VARCHAR | |-------------+-------------| spectra table | column name | type | |----------------+-------------| | id | PRIMARY KEY | | name | VARCHAR | | index | INT | | spectrum_type | INT | | representation | INT | | run_id | FOREIGN KEY | |----------------+-------------| datapoints table | column name | type | |-------------+-------------| | id | PRIMARY KEY | | spectrum_id | FOREIGN KEY | | mz | DOUBLE | | num_counts | DOUBLE | | index | INT | |-------------+-------------| Is this reasonable?

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  • Approach for altering Primary Key from GUID to BigInt in SQL Server related tables

    - by Tom
    I have two tables with 10-20 million rows that have GUID primary keys and at leat 12 tables related via foreign key. The base tables have 10-20 indexes each. We are moving from GUID to BigInt primary keys. I'm wondering if anyone has any suggestions on an approach. Right now this is the approach I'm pondering: Drop all indexes and fkeys on all the tables involved. Add 'NewPrimaryKey' column to each table Make the key identity on the two base tables Script the data change "update table x, set NewPrimaryKey = y where OldPrimaryKey = z Rename the original primarykey to 'oldprimarykey' Rename the 'NewPrimaryKey' column 'PrimaryKey' Script back all the indexes and fkeys Does this seem like a good approach? Does anyone know of a tool or script that would help with this? TD: Edited per additional information. See this blog post that addresses an approach when the GUID is the Primary: http://www.sqlmag.com/blogs/sql-server-questions-answered/sql-server-questions-answered/tabid/1977/entryid/12749/Default.aspx

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  • Test sorting through QTP

    - by onkar
    There is a java table in my application which has 1 column & 5 rows. Contents of rows are as below. These contents are arranged in descending order 172-18-zfs MKTLAB NFSVOL datastore1 datastore1(1) after clicking on column header it get sort in asceding order & order is like this datastore1(1) datastore1 NFSVOL MKTLAB 172-18-zfs Through QTP i want to check whether this sortig is correct or not. I have used sort() method of dictionary but it doesnt give expected result. It just sort according to alphabatical order. In expected sorting order 1st priority should be to small letter then to capital letter then to number.

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  • How can I access the value of a checkbox without a postback?

    - by Starwfanatic
    I have a radgrid controlling access to an application for users. There are two columns, a 'name' column and a checkbox 'access' column representing their current access permission. the checkboxes are populated from a database. I would like the to change the checkboxes to grant or deny access to the users I specify. Since there are alot of users I would like to make multiple changes and use a submit button to write the changes to the database. I do not want to postback with each checkbox change and wait for the page to "blink". My problem is that with the checkbox postback disabled, when I click submit, the value of the checkboxes are not registering the changes I make. I need a way to access the current client-side state of the checkbox or some workaround to accomplish this. Thanks in advance!

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  • Mysql two table query

    - by Sergio
    I'm using two tables. First (friendlist), which contains users who are on the list of friends and the other table (members) that contains the basic data of the users. Friendlist looks like: id | myid | date | user ----------------------------------------- 001 | 50624 | 2010-01-01 | 32009 002 | 41009 | 2010-05-05 | 50624 003 | 50624 | 2010-03-02 | 23007 The column "myid" contains members who added other users (those from column "user") to their frindlist. I want to get the list of all users that I have added to list and those who add me to their friendlist. In this example, if my id is 50624, the list would look like: | allfriends | --------------- 32009 41009 23007 Then I need to check all users from "allfriend" list with data from the table "members". I want to get only the users with status 1. The members table looks like: id | status | photo -------------------------------- 32009 | 0 | 1.jpg 41009 | 1 | 2.jpg 23007 | 1 | 3.jpg How this mysql query should look like? Thanks for any help.

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  • Constant in Hibernate Mapping Files

    - by bertolami
    I would like to add a value object to a mapped class where one column is fixed depending of the class that contains the component. How can I do something like this? <component name="aComponent"> <property name="abc" column="cde"/> <property name="xyz" value="FIXED"/> </component> Unfortunatly, the value attribute does not exist. Is there another way to apply a constant value to property? Thanks in advance.

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  • Data frame linear fit in R

    - by user1247384
    This is perhaps a simple question, but I am n00b.Say I have a data frame with a bunch of columns. I need to call lm function over the column 1 and 2, 1 and 3, and so on. So basically I need to loop over all columns and store the results of the fit as I build the model. The problem I am running into is that lm(df[1]~df[2], data = df) doesnt work. In this case df is the data frame object and df[1] is the first column. What is a good way to do this in a loop, as in access the columns of df in an iterative fashion. Thanks.

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  • jQuery Tablesorter - disabled headers show progress bar, sortEnd never triggered

    - by McGirl
    I'm combining Tablesorter's 'disable headers using options' function and the 'trigger sortStart / sortEnd' function and have run into an issue. The following code works fine for the most part, BUT: when you click on a disabled header, the progress-indicating #overlay div appears and never goes away. <script type="text/javascript" id="js"> $(document).ready(function() { // call the tablesorter plugin, the magic happens in the markup $("#projectTable").tablesorter({ // pass the headers argument and assing a object headers: { // assign the secound column (we start counting zero) 1: { // disable it by setting the property sorter to false sorter: false }, // assign the third column (we start counting zero) 2: { // disable it by setting the property sorter to false sorter: false } } }); //assign the sortStart event $("#projectTable").bind("sortStart",function() { $("#overlay").show(); }).bind("sortEnd",function() { $("#overlay").hide(); }); }); </script> Any ideas on how I could fix this so that nothing at all happens when the disabled headers are clicked? Thanks!

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  • Flex bug?? Get messed up stacked ColumnChart with type="100%"

    - by Nir
    I am trying to do a stacked Column chart with type="100%" and a mixture of positive and negative values. When all the values are positive, is functions well, but when negative numbers come to the game, it looks totally messed up. When I also look at Adobe documentation (look here), I see the following code for stacked column chart involving negative numbers: <?xml version="1.0"?> <!-- charts/StackedNegative.mxml --> <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"> <mx:Script><![CDATA[ import mx.collections.ArrayCollection; [Bindable] public var expenses:ArrayCollection = new ArrayCollection([ {Month:"Jan", Profit:-2000, Expenses:-1500}, {Month:"Feb", Profit:1000, Expenses:-200}, {Month:"Mar", Profit:1500, Expenses:-500} ]); ]]></mx:Script> <mx:Panel title="Column Chart"> <mx:ColumnChart id="myChart" dataProvider="{expenses}" showDataTips="true"> <mx:horizontalAxis> <mx:CategoryAxis dataProvider="{expenses}" categoryField="Month" /> </mx:horizontalAxis> <mx:series> <mx:ColumnSet type="stacked" allowNegativeForStacked="true"> <mx:series> <mx:ColumnSeries xField="Month" yField="Profit" displayName="Profit" /> <mx:ColumnSeries xField="Month" yField="Expenses" displayName="Expenses" /> </mx:series> </mx:ColumnSet> </mx:series> </mx:ColumnChart> <mx:Legend dataProvider="{myChart}"/> </mx:Panel> </mx:Application> It works fine. But try to change: <mx:ColumnSet type="stacked" allowNegativeForStacked="true"> to: <mx:ColumnSet type="100%" allowNegativeForStacked="true"> and you'll see that it doesn't on January data, where both values are negative, the chart shows as if they are positive, and on the other two where one value is positive and the other is negative, it shows only the positive part as 100%... Isn't it a Flex Bug? I have my own case with such data and it behaves wrong the same way. I'd expect that if it has 800 stacked on -200, it will show 80% up and 20% down, totalling 100%. BTW: Using Flex 4, though these are all mx components. Thanks a lot and regards from Berlin, Germany, Nir.

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  • How can we block the user from unchecking a DataGridView checkbox?

    - by hawbsl
    We have a DataGridViewCheckBox column bound to a boolean property in our class. The property setter has some logic which says that under certain conditions a True flag cannot be changed, ie, it stays checked forever. This is on a per record basis. So the entire column can't be readonly, only certain rows. Pseudo code: Public Property Foo() As Boolean Get Return _Foo End Get Set(ByVal value As Boolean) If _Foo And Bar And value = False Then //do nothing, in this scenario once you're true, you stay true Else _Foo = value End If End Set End Property Databinding is handling all of this fine, except that the checkbox is visibly cleared when it's clicked. Then, of course, when the binding / setter is fired (as you move off that cell) it is restored to its checked status per the underlying logic. Ultimately it doesn't matter too much but it's a clumsy bit of UI. How can we intercept the user's click and keep it checked?

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  • Fixing "Lock wait timeout exceeded; try restarting transaction" for a 'stuck" Mysql table?

    - by Tom
    From a script I sent a query like this thousands of times to my local database: update some_table set some_column = some_value I forgot to add the where part, so the same column was set to the same a value for all the rows in the table and this was done thousands of times and the column was indexed, so the corresponding index was probably updated too lots of times. I noticed something was wrong, because it took too long, so I killed the script. I even rebooted my computer since them, but something stuck in the table, because simple queries take a very long time to run and when I try dropping the relevant index it fails with this message: Lock wait timeout exceeded; try restarting transaction It's an innodb table, so stuck the transaction is probably implicit. How can I fix this table and remove the stuck transaction from it?

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  • how to write sql script to achieve the following

    - by 3nigma
    hi, so i have a table lets say call it "tbl.items" and there is a column "title" in "tbl.items" i want to loop through each row and for each "title" in "tbl.items" i want to do following: the column has the datatype nvarchar(max) and contains a string... filter the string to remove words like in,out, where etc (stopwords) compare the rest of the string to a predefined list and if there is a match perform some action which involves inserting data in other tables as well.. the problem is im ignotent when it comes to writing T-sql scripts, plz help and guide me how can i achieve this? whether it can be achieved by writing a sql script?? or i have to develope a console application in c# or anyother language?? im using mssql server 2008 thanks in advance

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  • Difference in select for update of ... in Oracle Database 10g and 11g

    - by sax
    Hi, I found out that Oracle Database 10g and 11g treat the following PL/SQL block differently (I am using scott schema for convenience): DECLARE v_ename bonus.ename%TYPE; BEGIN SELECT b.ename INTO v_ename FROM bonus b JOIN emp e ON b.ename = e.ename JOIN dept d ON d.deptno = e.deptno WHERE b.ename = 'Scott' FOR UPDATE OF b.ename; END; / While in 10g (10.2) this code ends successfully (well NO_DATA_FOUND exception is raised but that is expected), in 11g (11.2) it raises exception "column ambiguously defined". And that is definitely not expected. It seems like it does not take into account table alias because I found out that when I change the column in FOR UPDATE OF e.empno (also does not work) to e.mgr (which is unique) it starts working. So is this some error in 11g? Any thoughts?

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  • Subquery Doctrine Couldn't find class

    - by yosesita
    I'm trying to create a query like this one : $q = Doctrine_Query::create() -select('p.nombre') -addSelect('(select count(*) from alojamiento a left join localidad l on a.localidad_id=l.id where p.id=l.provincia_id and a.activo=true)') -from('provincia p'); but it fails : error 500, couldn't find class a. And : $q = Doctrine_Query::create() -select('nombre') -addSelect('(select count(*) from alojamiento left join localidad on alojamiento.localidad_id=localidad.id where provincia.id=localidad.provincia_id and alojamiento.activo=true)') -from('provincia'); leads to : SQLSTATE[42S22]: Column not found: 1054 Unknown column 'a.localidad_id' in 'on clause'. Any help would be greatly appreciated !

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  • How to discover table properties from SQLAlchemy mapped object

    - by ssaboum
    Hi, My point is i have a class mapped with a table, in my case in a declarative way, and i want to "discover" table properties, columns, names, relations, from this class : engine = create_engine('sqlite:///' + databasePath, echo=True) # setting up root class for declarative declaration Base = declarative_base(bind=engine) class Ship(Base): __tablename__ = 'ships' id = Column(Integer, primary_key=True) name = Column(String(255)) def __init__(self, name): self.name = name def __repr__(self): return "<Ship('%s')>" % (self.name) So now my goal is from the "Ship" class to get the table columns and their properties from another piece of code. I guess i can deal with it using instrumentation but is there any way provided by the SQLAlchemy API ? Thank you.

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  • Oracle TIMESTAMP w/ timezone data type confusion

    - by JuiceBox1337
    When would you use TIMESTAMP w/ timezone as opposed to TIMESTAMP w/ local time zone? When data is stored in a column of data type TIMESTAMP w/ local tz, the data is normalized to the database time zone, and the time zone displacement is not stored as part of the column data. When users retrieve the data, Oracle returns it in the users' local session time zone. Isn't that much more useful? I can't think of a reason why I'd want to use TIMESTAMP w/ timezone and get back some gobble gook with a UTC offset.

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  • How to replace&add the dataframe element by another dataframe in Python Pandas?

    - by bigbug
    Suppose I have two data frame 'df_a' & 'df_b' , both have the same index structure and columns, but some of the inside data elements are different: >>> df_a sales cogs STK_ID QT 000876 1 100 100 2 100 100 3 100 100 4 100 100 5 100 100 6 100 100 7 100 100 >>> df_b sales cogs STK_ID QT 000876 5 50 50 6 50 50 7 50 50 8 50 50 9 50 50 10 50 50 And now I want to replace the element of df_a by element of df_b which have the same (index, column) coordinate, and attach df_b's elements whose (index, column) coordinate beyond the scope of df_a . Just like add a patch 'df_b' to 'df_a' : >>> df_c = patch(df_a,df_b) sales cogs STK_ID QT 000876 1 100 100 2 100 100 3 100 100 4 100 100 5 50 50 6 50 50 7 50 50 8 50 50 9 50 50 10 50 50 How to write the 'patch(df_a,df_b)' function ?

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  • Can I Automap a tree hierarchy with Fluent NHibernate?

    - by NakChak
    Is it possible to auto map a simple nested object structure? Something like this: public class Employee : Entity { public Employee() { this.Manages = new List<Employee>(); } public virtual string FirstName { get; set; } public virtual string LastName { get; set; } public virtual bool IsLineManager { get; set; } public virtual Employee Manager { get; set; } public virtual IList<Employee> Manages { get; set; } } It causes the following error at run time: Repeated column in mapping for collection: SharpKtulu.Core.Employee.Manages column: EmployeeFk Is it possible to automap this sort of structure, or do I have override the auto mapper for this sort of structure?

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  • Postgesql select from 2 tables. Joins?

    - by Daniel
    I have 2 tables that look like this: Table "public.phone_lists" Column | Type | Modifiers ----------+-------------------+-------------------------------------------------------------------- id | integer | not null default nextval(('"phone_lists_id_seq"'::text)::regclass) list_id | integer | not null sequence | integer | not null phone | character varying | name | character varying | and Table "public.email_lists" Column | Type | Modifiers ---------+-------------------+-------------------------------------------------------------------- id | integer | not null default nextval(('"email_lists_id_seq"'::text)::regclass) list_id | integer | not null email | character varying | I'm trying to get the list_id, phone, and emails out of the tables in one table. I'm looking for an output like: list_id | phone | email ---------+-------------+-------------------------------- 0 | | [email protected] 0 | | [email protected] 0 | | [email protected] 0 | | [email protected] 0 | | [email protected] 1 | 15555555555 | 1 | 15555551806 | 1 | 15555555508 | 1 | 15055555506 | 1 | 15055555558 | 1 | | [email protected] 1 | | [email protected] I've come up with select pl.list_id, pl.phone, el.email from phone_lists as pl left join email_lists as el using (list_id); but thats not quite right. Any suggestions?

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  • How to point to other table's ID with hibernate?

    - by Wilhelm
    The problem: let's say I have two tables Client, and Product, in which Client has its primary key and a column called products (that points to pk's in Product table)... ok, if I need products to point only one row, it's nice, but if I need it to point for... 1000 rows in Product table, the products column would have to be larger enought... but I can't predict this situation. So, how could I design my table and how would I use hibernate with it, to achieve that "pointing" in a optmized and maybe "easy" way. NOTE: I excluded some columns of the "design" presented here, just to keep the simplicity.

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  • mysql left join

    - by user1019538
    I have two table one is index and another is the price structure as under table : index : column : trandate ,indexcode Table : price : Column: trandate,symbol,price i want to know the missing price. I issue the query select i.trandate,i.indexcode,p.trandate,p.price from index i left join price p on i.trandate = p.trandate where p.symbol='ABC' and indexcode="New" the above query does not show the null date even though various price in missing in price table. Only reason i understand is that the index table does not have the symbol field that's why...but as per theory if you want to show all the rows of one table and only the match value of another table then use the left or right join query...please anybody can help

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  • Style Data in a gridview which dynamically generates the columns

    - by Coesy
    I have built a dynamic gridview using the following code grdVariants.Columns.Clear(); int i = 0; foreach (DataColumn column in options.Columns) { grdVariants.Columns.Add(new GridViewColumn { Header = column.ColumnName, DisplayMemberBinding = new Binding(string.Format("[{0}]", i++)) }); } This will dynamically generate my columns at runtime, I then bind the data using lstVariantsGrid.DataContext = options; lstVariantsGrid.Items.Refresh(); This all works great and shows the data in the correct columns etc, the only issue i have is that I can't style the rows like I would in xaml as it is all an unknown quantity until runtime. Can anyone offer some advice on how I might go about doing this? One of the biggest problems I have is that one of the columns needs to display the image rather than just the path which it currently shows, as well as fiddling with fonts and colors etc. Thanks for your time.

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  • Using stored procedures to generate RDLC report in C#

    - by NDraskovic
    I'm making an application that generates reports for my client. I'm using his database that contains stored procedures which return the data needed for the reports. The problem is that I don't know how to execute them from the application (more specific the TableAdapter in my dataset). When I use the visual aid to create the TableAdapter, it shows the error "Invalid object named #table1". This is weird because there is a temporary table called #table1 in the stored procedure. When I try to do the whole job programmatically, I get the exception Incorrect syntax near '.'. An object or column name is missing or empty. For SELECT INTO statements, verify each column has a name. For other statements, look for empty alias names. Aliases defined as "" or [] are not allowed. Change the alias to a valid name. I created a DataTable that has identical structure as the result of the stored procedure, but I still get the same exception

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