Search Results

Search found 33021 results on 1321 pages for 'database sessions'.

Page 319/1321 | < Previous Page | 315 316 317 318 319 320 321 322 323 324 325 326  | Next Page >

• Why does HIbernate require no argument constructor?

  - by kunjaan

  The no-argument constructor is a requirement (tools like Hibernate use reflection on this constructor to instantiate objects). I got this hand-wavy answer but could somebody explain further? Thanks

  Read the article

• How do I write this MySQL Query? (datetime)

  - by alex

  Suppose I have a DateTime field called "time_before" I want to insert a datetime that is 1 hour before the now() time. INSERT INTO mytable(time_before) VALUES(now()-3600 seconds)...something like this, right?

  Read the article

• Transaction Isolation on select, insert, delete

  - by Bradford

  What could possibly go wrong with the following transaction if executed by concurrent users in the default isolation level of READ COMMITTED? BEGIN TRANSACTION SELECT * FROM t WHERE pid = 10 and r between 40 and 60 -- ... this returns tid = 1, 3, 5 -- ... process returned data ... DELETE FROM t WHERE tid in (1, 3, 5) INSERT INTO t (tid, pid, r) VALUES (77, 10, 35) INSERT INTO t (tid, pid, r) VALUES (78, 10, 37) INSERT INTO t (tid, pid, r) VALUES (79, 11, 39) COMMIT

  Read the article

• Is it a good practice to implement aggregate routes in Entity Framework 4?

  - by Kohan

  Having just started working on a new project using Entity Framework 4, I spoke to some of the other team that use NHibernate for advice. They implement aggregate routes on their entities, so instead of adding an order through the orders entity, they would add it through customer.order by having an addOrder method on customer. This is the approach I have taken but I am, alas, running into problems. These are issues that I hope to work out, but it got me thinking ... Is this a good way to work or am I fighting an uphill battle unnecessarily?

  Read the article

• Using memory-based cache together with conventional cache

  - by Industrial

  Hi! Here's the deal. We would have taken the complete static html road to solve performance issues, but since the site will be partially dynamic, this won't work out for us. What we have thought of instead is using memcache + eAccelerator to speed up PHP and take care of caching for the most used data. Here's our two approaches that we have thought of right now: Using memcache on all<< major queries and leaving it alone to do what it does best. Usinc memcache for most commonly retrieved data, and combining with a standard harddrive-stored cache for further usage. The major advantage of only using memcache is of course the performance, but as users increases, the memory usage gets heavy. Combining the two sounds like a more natural approach to us, even though the theoretical compromize in performance. Memcached appears to have some replication features available as well, which may come handy when it's time to increase the nodes. What approach should we use? - Is it stupid to compromize and combine the two methods? Should we insted be focusing on utilizing memcache and instead focusing on upgrading the memory as the load increases with the number of users? Thanks a lot!

  Read the article

• what is the question for the query?

  - by Kevinniceguy

  Sorry...I mean what question will be for this query? SELECT SUM(price) FROM Room r, Hotel h WHERE r.hotelNo = h.hotelNo and hotelName = 'Paris Hilton' and roomNo NOT IN (SELECT roomNo FROM Booking b, Hotel h WHERE (dateFrom <= CURRENT_DATE AND dateTo >= CURRENT_DATE) AND b.hotelNo = h.hotelNo AND hotelName = 'Paris Hilton');

  Read the article

• Natural vs surrogate keys on support tables

  - by Bugeo

  I have read many articles about the battle between natural versus surrogate primary keys. I agree in the use of surrogate keys to identify records of tables whose contents are created by the user. But in the case of supporting tables what should I use? For example, in a hypothetical table "orderStates". If you use a natural key would have the following data: TABLE ORDERSTATES {ID: "NEW", NAME: "New"} {ID: "MANAGEMENT" NAME: "Management"} {ID: "SHIPPED" NAME: "Shipped"} If I use a surrogate key would have the following data: TABLE ORDERSTATES {ID: 1 CODE: "NEW", NAME: "New"} {ID: 2 CODE: "MANAGEMENT" NAME: "Management"} {ID: 3 CODE: "SHIPPED" NAME: "Shipped"} Now let's take an example: a user enters a new order. In the case in which use natural keys, in the code I can write this: newOrder.StateOrderId = "NEW"; With the surrogate keys instead every time I have an additional step. stateOrderId_NEW = .... I retrieve the id corresponding to the recod code "NEW" newOrder.StateOrderId = stateOrderId_NEW; The same will happen every time I have to move the order in a new status. So, in this case, what are the reason to chose one key type vs the other one?

  Read the article

• Is It Possible to have a primary key and auto increment key associated to two fields respectively?

  - by Parth

  Is It Possible to have a primary key and auto increment key associated to two fields respectively? Like wise, In a table there are 3 fields, say, ID, name and age.. Then is it possible that "ID is autoincrment key and name is primary key"?

  Read the article

• BI with Django?

  - by Helmut

  Is there a way to develop Bi (Business Intelligence) solutions with Django? Therefore it should be possible to define models with more than one Datasource. Is anybody out there who has experienced BI with Django? How could it work ?

  Read the article

• Can I use EXISTS keyword in sql query for assignment of result

  - by Shantanu Gupta

  Can I assign a value with EXISTS in the query. Currently it is giving me error Incorrect syntax near '='. But when I uses this query only it runs as expected. IF EXISTS (SELECT @PK_LOGIN_ID=PK_LOGIN_ID FROM dbo.M_LOGIN WHERE LOGIN_NAME=@LOGIN_NAME AND PASSWORD=@PASSWORD AND FK_ROLE_ID=@FK_ROLE_ID) RETURN @PK_LOGIN_ID ELSE RETURN 0

  Read the article

• How to resolve ORA-011033: ORACLE initialization or shutdown in progress

  - by rohancragg

  When trying to connect to an ORACLE user via TOAD (Quest Software) or any other means (Oracle Enterprise Manager) I simply get the error: ORA-011033: ORACLE initialization or shutdown in progress [in the spirit of StackOverflow I will answer this one myself - at least I'll relate how I resolved it in my case - please also relate your own such adventures...]

  Read the article

• Using a remote PHP service with Flex (Flash Builder) AIR Application?

  - by Chrisc

  Hello, I'm developing a Adobe AIR application using Flash Builder 4. This app needs to access a remote PHP service which is being hosted on a remote web server. I am having troubles figuring out how to add a PHP data service which uses a remote service. I can add the PHP data service in Flash Builder as a service hosted on localhost, but given that this will not be feasible when the application is deployed, will not work. Does anyone know how to connect a Flash Builder (Flex) project to a remote PHP data service? Thanks, Chris

  Read the article

• Tool Compare the tables in two different databeses

  - by user191124

  I am using Toad. Frequently i need to compare tables in two different test environments. the tables present in them are same but the data differs. i just need to know what are the differences in the same tables which are in two different data bases.Are there any tools which can be installed on windows and use it to compare. Much appreciate your help:)

  Read the article

• How to achieve high availability?

  - by tanyehzheng

  My boss wants to have a system that takes into concern of continent wide catastrophic event. He wants to have two servers in US and two servers in Asia (1 login server and 1 worker server in each continent). In the event that earthquake breaks the connection between the two continents, both should work alone. When the connection is revived, they should sync each other back to normal. External cloud system not allowed as he has no confidence. The system should take into account of scalability which means addition of new servers should be easy to configure. The servers should be load balanced. The connection between the servers should be very secure(encrypted and send through SSL although SSL takes care of encryption). The system should let one and only one user log in with one account. (beware of latency between continent and two users sharing account may reach both login server at the same time) Please help. I'm already at the end of my wit. Thank you in advance.

  Read the article

• MySQL - query to return CSV in a field?

  - by StackOverflowNewbie

  Assume I have the following tables: TABLE: foo - foo_id (PK) TABLE: tag - tag_id (PK) - name TABLE: foo_tag - foo_tag_id (PK) - foo_id (FK) - tag_id (FK) How do I query this so that I get a result like this: ========================== | foo_id | tags | ========================== | 1 | foo, bar | | 2 | foo | | 3 | bar | -------------------------- Basically, I need all of foo's tags in one column, comma separated. Possible in MySQL?

  Read the article

• Are there any examples/tutorials of using Spring 3.0 with Cassandra as a backend?

  - by zeroDivisible

  Hello, As I had written in title, I am trying to learn Spring 3.0 (I already know Django, Pylons and few simpler MVC frameworks) and try to use Cassandra as a backend for my web application. Are there any real world examples of doing this? Or maybe some tutorials? I know about the existence of documentation of both technologies, yet I am looking for something "faster" to read and get me rolling.

  Read the article

• Edit primary keys in Symfony auto-generated admin

  - by madkingbilly

  I need to edit primary keys in several tables. By default, symfony hides primary keys in New/Edit forms. For example, can't edit table 'Tags' with only field 'tag' which is PK. Adding integer ID to this table is not exactly good db design. Thanks in advance for your help.

  Read the article

• Detecting changes between rows with same ID

  - by Noah

  I have a table containing some names and their associated ID, along with a snapshot: snapshot, id, name I need to identify when a name has changed for an id between snapshots. For example, in the following data: 1, 0, 'MOUSE_SPEED' 1, 1, 'MOUSE_POS' 1, 2, 'KEYBOARD_STATE' 2, 0, 'MOUSE_BUTTONS' 2, 1, 'MOUSE_POS' 2, 2, 'KEYBOARD_STATE' ...the meaning of id 0 changed with snapshot 2, but the others remained the same. I'd like to construct a query that (ideally) returns: 1, 0, 'MOUSE_SPEED' 2, 0, 'MOUSE_BUTTONS' I am using PostgreSQL v8.4.2.

  Read the article

• What's wrong with this SQL query?

  - by ThinkingInBits

  I have two tables: photographs, and photograph_tags. Photograph_tags contains a column called photograph_id (id in photographs). You can have many tags for one photograph. I have a photograph row related to three tags: boy, stream, and water. However, running the following query returns 0 rows SELECT p.* FROM photographs p, photograph_tags c WHERE c.photograph_id = p.id AND (c.value IN ('dog', 'water', 'stream')) GROUP BY p.id HAVING COUNT( p.id )=3 Is something wrong with this query?

  Read the article

• using dummy row with NOT NULL to solve DEFAULT NULL

  - by Tony38

  I know having DEFAULT NULLS is not a good practice but I have many optional lookup values which are FK in the system so to solve this issue here is what i am doing: I use NOT NULL for every FK / lookup colunms. I have the first row in every lookup table which is PK id = 1 as a dummy row with just "none" in all the columns. This way I can use NOT NULL in my schema and if needed reference to the none row values PK =1 for FKs which do not have any lookup value. Is this a good design or any other work arounds? EDIT: I have: Neighborhood table Postal table. Every neighborhood has a city, so the FK can be NOT NULL. But not every postal code belongs to a neighborhood. Some do, some don't depending on the country. So if i use NOT NULL for the FK between postal and neighborhood then I will be screwed as there has to be some value entered. So what i am doing in essence is: have a row in every table to be a dummy row just to link the FKs. This way row one in neighborhood table will be: n_id = 1 name =none etc... In postal table I can have: postal_code = 3456A3 FK (city) = Moscow FK (neighborhood_id)=1 as a NOT NULL. If I don't have a dummy row in the neighborhood lookup table then I have to declare FK (neighborhood_id) as a Default null column and store blanks in the table. This is an example but there is a huge number of values which will have blanks then in many tables.

  Read the article

• Passing BLOB/CLOB as parameter to PL/SQL function

  - by Ula Krukar

  I have this procedure i my package: PROCEDURE pr_export_blob( p_name IN VARCHAR2, p_blob IN BLOB, p_part_size IN NUMBER); I would like for parameter p_blob to be either BLOB or CLOB. When I call this procedure with BLOB parameter, everything is fine. When I call it with CLOB parameter, I get compilation error: PLS-00306: wrong number or types of arguments in call to 'pr_export_blob' Is there a way to write a procedure, that can take either of those types as parameter? Some kind of a superclass maybe?

  Read the article

• Does Ruby on Rails "has_many" array provide data on a "need to know" basis?

  - by Jian Lin

  On Ruby on Rails, say, if the Actor model object is Tom Hanks, and the "has_many" fans is 20,000 Fan objects, then actor.fans gives an Array with 20,000 elements. Probably, the elements are not pre-populated with values? Otherwise, getting each Actor object from the DB can be extremely time consuming. So it is on a "need to know" basis? So does it pull data when I access actor.fans[500], and pull data when I access actor.fans[0]? If it jumps from each record to record, then it won't be able to optimize performance by doing sequential read, which can be faster on the hard disk because those records could be in the nearby sector / platter layer -- for example, if the program touches 2 random elements, then it will be faster just to read those 2 records, but what if it touches all elements in random order, then it may be faster just to read all records in a sequential way, and then process the random elements. But how will RoR know whether I am doing only a few random elements or all elements in random?

  Read the article

• MySQL Query order by numer of rows?

  - by Clemens

  hi, i have a mysql table for votes. there's am id, a project_id and a vote field (which is 1 if a specific project is voted). now i want to generate a ranking from those entries. is there a way to get the number of votes for each project_id and automatically sort the entries by the number of TRUE votes of a project with a single mysql query? Or do you know a php way? e.g. ID - Project ID - Vote 1 - 2 - 1 2 - 2 - 1 3 - 1 - 1 == Project Nr. 2 has 2 Votes Project Nr. 1 has 1 Vote Thanks in advance!

  Read the article

• SQL SERVER - Detecting non-indexed columns but used in WHERE clause

  - by Vadi

  How to detect a column included in WHERE clause but used in indexed? Little Background: Until the time the table has few number of records things will be okay, once it started having millions of records then index should be created for a column which is used in WHERE clauses in stored procs, inline queries etc., Since we have hundreds of stored procs and queries that often gets changed by the devs I wanted to have a automated way of identifying those columns that are used in WHERE clauses but not an index is created. How to do that in SQL SERVER 2008?

  Read the article

• Is it possible to partition more than one way at a time in SQL Server?

  - by meeting_overload

  I'm considering various ways to partition my data in SQL Server. One approach I'm looking at is to partition a particular huge table into 8 partitions, then within each of these partitions to partition on a different partition column. Is this even possible in SQL Server, or am I limited to definining one parition column+function+scheme per table? I'm interested in the more general answer, but this strategy is one I'm considering for Distributed Partitioned View, where I'd partition the data under the first scheme using DPV to distribute the huge amount of data over 8 machines, and then on each machine partition that portion of the full table on another parition key in order to be able to drop (for example) sub-paritions as required.

  Read the article

< Previous Page | 315 316 317 318 319 320 321 322 323 324 325 326  | Next Page >