Search Results

Search found 42428 results on 1698 pages for 'database query'.

Page 490/1698 | < Previous Page | 486 487 488 489 490 491 492 493 494 495 496 497  | Next Page >

  • When does a query/subquery return a NULL and when no value at all?

    - by AspOnMyNet
    a) If a query/subquery doesn’t find any matching rows, then it either returns NULL or no value at all, thus not even a NULL value. Based on what criteria does a query/subquery return a NULL and when doesn’t it return any results, not even a NULL value? b) I assume a scalar subquery will always return NULL, when no matching rows are found? I assume most-outer scalar query also returns NULL if no rows are found? c) SELECT FirstName, LastName, YEAR(BirthDate) FROM Persons WHERE YEAR(BirthDate) IN (SELECT YearReleased FROM Albums); If subquery finds no results, is then a WHERE clause of an outer query translated into WHERE YEAR(BirthDate) IN (null); ? If instead WHERE clause is translated into WHERE YEAR(BirthDate) IN(); then shouldn’t that be an error condition, since how can YEAR(BirthDate) value be compared to nothing? thanx

    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

  • How Implement a system to determine if a milestone has been reached

    - by Luc M
    I have a table named stats player_id team_id match_date goal assist` 1 8 2010-01-01 1 1 1 8 2010-01-01 2 0 1 9 2010-01-01 0 5 ... I would like to know when a player reach a milestone (eg 100 goals, 100 assists, 500 goals...) I would like to know also when a team reach a milestone. I want to know which player or team reach 100 goals first, second, third... I thought to use triggers with tables to accumulate the totals. Table player_accumulator (and team_accumulator) table would be player_id total_goals total_assists 1 3 6 team_id total_goals total_assists 8 3 1 9 0 5 Each time a row is inserted in stats table, a trigger will insert/update player_accumulator and team_accumulator tables. This trigger could also verify if player or team has reached a milestone in milestone table containing numbers milestone 100 500 1000 ... A table player_milestone would contains milestone reached by player: player_id stat milestone date 1 goal 100 2013-04-02 1 assist 100 2012-11-19 There is a better way to implements a "milestone" ? There is an easiest way without triggers ? I'm using PostgreSQL

    Read the article

  • What is a good DBMS for archiving?

    - by Thomas.Winsnes
    I've been stuck in a MsSql/MySql world now for a few years, and I've decided to spread my wings a little further. At the moment I'm researching which DBMS is good at things needed when archiving data. Eg. lots of writes and low reads. I've seen the NoSQL crusade, but I have a very RDBMS mindset, so I'm a bit skeptical. Anyone have any suggestions? Or even any pointers to where there are some benchmarks etc for this kind of stuff. Thank you :) Thomas

    Read the article

  • Is copying /var/lib/mysql a good alterntive to mysqldump?

    - by kemp
    Since I'm making a full backup of my entire debian system, I was thinking if having a copy of /var/lib/mysql directory is a viable alternative to dumping tables with mysqldump. are all informations needed contained in that directory? can single tables be imported in another mysql? can there be problems while restoring those files on a (probably slightly) different mysql server version?

    Read the article

  • What's the best way to migrate a Django DB from SQLite to MySQL?

    - by Inshim
    I need to migrate my db from sqlite to mysql, and the various tools/scripts out there are too many for me to easily spot the safest and most elegant solution. This seemed to me nice http://djangosnippets.org/snippets/14/ but appears to be 3 years since getting an update which is worrying.. Can you recommend a solution that is known to be reliable with Django 1.1.1 ?

    Read the article

  • Is there an ORM that supports composition w/o Joins

    - by Ken Downs
    EDIT: Changed title from "inheritance" to "composition". Left body of question unchanged. I'm curious if there is an ORM tool that supports inheritance w/o creating separate tables that have to be joined. Simple example. Assume a table of customers, with a Bill-to address, and a table of vendors, with a remit-to address. Keep it simple and assume one address each, not a child table of addresses for each. These addresses will have a handful of values in common: address 1, address 2, city, state/province, postal code. So let's say I'd have a class "addressBlock" and I want the customers and vendors to inherit from this class, and possibly from other classes. But I do not want separate tables that have to be joined, I want the columns in the customer and vendor tables respectively. Is there an ORM that supports this? The closest question I have found on StackOverflow that might be the same question is linked below, but I can't quite figure if the OP is asking what I am asking. He seems to be asking about foregoing inheritance precisely because there will be multiple tables. I'm looking for the case where you can use inheritance w/o generating the multiple tables. Model inheritance approach with Django's ORM

    Read the article

  • Datamapper Clone Record w/ New ID

    - by BouncePast
    class Item include DataMapper::Resource property :id, Serial property :title, String end item = Item.new(:title = 'Title 1') # :id = 1 item_clone = Item.first(:id = 1).clone item_clone.save This does "clone" the object as described but how can this be done so it applies a different ID once the record is saved, e.g. #

    Read the article

  • PHP mySQL - replace some string inside string

    - by apis17
    i want to replace ALL comma , into ,<space> in all address table in my mysql table. For example, +----------------+----------------+ | Name | Address | +----------------+----------------+ | Someone name | A1,Street Name | +----------------+----------------+ Into +----------------+----------------+ | Name | Address | +----------------+----------------+ | Someone name | A1, Street Name| +----------------+----------------+ Thanks in advance.

    Read the article

  • PHP won't parse MySQL statements

    - by Hussain
    I just installed Apache 2.2.15/PHP 5.3.2/MySQL 5.1.44 on Windows Vista. Apache is working fine, PHP is functional, and MySQL works on the CLI. However, when I try to access MySQL via PHP, I get an error (Fatal error: Call to undefined function mysql_connect()). extension=php_mysql.dll and extension=php_mbstring.dll are uncommented in the php.ini file, and PHP is in the system path. There is no libmysql.dll in either the top level PHP directory or the ext directory. There's a libmySQL.dll file in the MySQL bin directory (which is also in the system path); I tried renaming it, but that doesn't do anything Also, in case anyone wants to know, I originally installed PHP using the MSI installer, but it was missing some DLLs, so I installed from the zip file. I think I've exhausted all my options. Any help on this problem would be very appreciated. Thanks in advance.

    Read the article

  • Reading directly from the Doctrine Searchable index table

    - by phidah
    I've got a Doctrine table with the Searchable behavior enabled. Whenever a record is created, an index is made in another table. I have a model called Entry and the behavior automatically created the table entry_index. My question now is: How can I - without using the search(...) methods of my model use the data from this table? I want to create a tag cloud of the words most used, and the data in the index table is exactly what I need.

    Read the article

  • Surrogate key for date dimension?

    - by Navin
    There are 2 school of thoughts : Use surrogate key preferbly in the format of YYYYMMDD as this will always be sequential. Eliminate Date dimension surrogate key and use actual date instead. My Questions to experts on dimension modeling are : 1> Which design would you prefer and why ? 2> How should we handle unknown values in each of the cases, Can we simply place NULL in Fact table for unknown dates as Foreign Key can be NULL (if no why)? 3> If we need to partition fact table on date column ,how would we achieve that in case 1. I am inclined towards using actual date and using NULL to represent UNKNOWN dates in fact table , as date related validation on fact can be done without need to look in to dimension table.

    Read the article

  • Do non-clustered indexes slow down inserts?

    - by mikeinmadison
    I'm working in Sql Server 2005. I have an event log table that tracks user actions, and I want to make sure that inserts into the table are as fast as possible. Currently the table doesn't have any indexes. Does adding a single non-clustered index slow down inserts at all? Or is it only clustered indexes that slow down inserts? Or should I just add a clustered index and not worry about it?

    Read the article

  • How do I modify an attribute across all rows in a table?

    - by prgmatic
    Hi folks, My apologies for asking such a novice question but, I need help building a script using either PHP or directly in MySQL that can do the following: Take the values of a column in a table (text) Change them into capitalized words (from "this is a title" to "This Is A Title") Replace the old values (uncapitalized) with the new values (capitalized). Thanks for the help and support.

    Read the article

  • Strategy in storing ad-hoc numbers/constants?

    - by Jiho Han
    I have a need to store a number of ad-hoc figures and constants for calculation. These numbers change periodically but they are different type of values. One might be a balance, a money amount, another might be an interest rate, and yet another might be a ratio of some kind. These numbers are then used in a calculation that involve other more structured figures. I'm not certain what the best way to store these in a relational DB is - that's the choice of storage for the app. One way, I've done before, is to create a very generic table that stores the values as text. I might store the data type along with it but the consumer knows what type it is so, in situations I didn't even need to store the data type. This kind of works fine but I am not very fond of the solution. Should I break down each of the numbers into specific categories and create tables that way? For example, create Rates table, and Balances table, etc.?

    Read the article

  • Cassandra Production ready on Windows?

    - by BlackTea
    Question anyone know of any success stories of Cassandra running on windows in a production environment? I'm doing some work on Cassandra and trying to find the correct platform for it currently the platform is windows running MS-SQLas the data store. what are the dis-advantages if any when running Cassandra on a windows environment.

    Read the article

  • wanting to move up from ms access, thinking .net? visual studio?

    - by Tristan Lear
    So I wrote a project-management program for a small business using Microsoft Access 2007. Now they've requested lots of additional features (timekeeping, privileged data tiers ...) I personally use Linux, but the whole office uses Windows. I'm relatively new to programming but like to teach myself using projects like this. I'm right on the edge on this -- I can't really tell what the path of least resistance here is: do I stay in access + VBA and teach myself a dying, annoying language -- while struggling against all the limitations of Access? Or do I move to something else? Python seems simple enough ... Whatever I use, i need to be able to offer a GUI.

    Read the article

< Previous Page | 486 487 488 489 490 491 492 493 494 495 496 497  | Next Page >