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  • Is it possible to use multiple desktop environments on same system?

    - by Kshitiz Sharma
    I am using Ubuntu 12.04. I want to try out KDE and other desktop environments. But I'm not sure if I'll like them enough to switch permanently. I want to be safe and make a transition in a piecemeal fashion. Is it possible to install KDE on Ubuntu and yet not do away with the default Unity shell? Could I install multiple desktop environments and switch between them by tweaking some startup configuration and then rebooting?

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  • Using stored procedure to call multiple packages at the same time from SSIS Catalog (SSISDB.catalog.start_execution) resulted in deadlock

    - by Kevin Shyr
    Refer to my previous post (http://geekswithblogs.net/LifeLongTechie/archive/2012/11/14/time-to-stop-using-ldquoexecute-package-taskrdquondash-a-way-to.aspx) about dynamic package calling and multiple packages execution in these posts: I only saw this twice, other times the stored procedure was able to call the packages successfully.  After the service pack, I haven't seen it...yet. http://support.microsoft.com/kb/2699720

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  • Should I use multiple column primary keys or add a new column?

    - by Covar
    My current database design makes use of a multiple column primary key to use existing data (that would be unique anyway) instead of creating an additional column assigning each entry an arbitrary key. I know that this is allowed, but was wondering if this is a practice that I might want to use cautiously and possibly avoid (much like goto in C). So what are some of the disadvantages I might see in this approach or reasons I might want a single column key?

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  • How can I sync between multiple threads so that their transaction ID be unique without using mutex?

    - by poly
    I'm writing an application in C that requires multiple threads to request a unique transaction ID from a function as shown below; struct list{ int id; struct list *next }; function generate_id() { linked-list is built here to hold 10 millions } How can I sync between two or more threads so that their transaction ID be unique among them without using mutex, is it possible? Please share anything even if I need to change linked list to something else.

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  • How to generate DELETE statements in PL/SQL, based on the tables FK relations?

    - by The chicken in the kitchen
    Is it possible via script/tool to generate authomatically many delete statements based on the tables fk relations, using Oracle PL/SQL? In example: I have the table: CHICKEN (CHICKEN_CODE NUMBER) and there are 30 tables with fk references to its CHICKEN_CODE that I need to delete; there are also other 150 tables foreign-key-linked to that 30 tables that I need to delete first. Is there some tool/script PL/SQL that I can run in order to generate all the necessary delete statements based on the FK relations for me? (by the way, I know about cascade delete on the relations, but please pay attention: I CAN'T USE IT IN MY PRODUCTION DATABASE, because it's dangerous!) I'm using Oracle DataBase 10G R2. This is the result I've written, but it is not recursive: This is a view I have previously written, but of course it is not recursive! CREATE OR REPLACE FORCE VIEW RUN ( OWNER_1, CONSTRAINT_NAME_1, TABLE_NAME_1, TABLE_NAME, VINCOLO ) AS SELECT OWNER_1, CONSTRAINT_NAME_1, TABLE_NAME_1, TABLE_NAME, '(' || LTRIM ( EXTRACT (XMLAGG (XMLELEMENT ("x", ',' || COLUMN_NAME)), '/x/text()'), ',') || ')' VINCOLO FROM ( SELECT CON1.OWNER OWNER_1, CON1.TABLE_NAME TABLE_NAME_1, CON1.CONSTRAINT_NAME CONSTRAINT_NAME_1, CON1.DELETE_RULE, CON1.STATUS, CON.TABLE_NAME, CON.CONSTRAINT_NAME, COL.POSITION, COL.COLUMN_NAME FROM DBA_CONSTRAINTS CON, DBA_CONS_COLUMNS COL, DBA_CONSTRAINTS CON1 WHERE CON.OWNER = 'TABLE_OWNER' AND CON.TABLE_NAME = 'TABLE_OWNED' AND ( (CON.CONSTRAINT_TYPE = 'P') OR (CON.CONSTRAINT_TYPE = 'U')) AND COL.TABLE_NAME = CON1.TABLE_NAME AND COL.CONSTRAINT_NAME = CON1.CONSTRAINT_NAME --AND CON1.OWNER = CON.OWNER AND CON1.R_CONSTRAINT_NAME = CON.CONSTRAINT_NAME AND CON1.CONSTRAINT_TYPE = 'R' GROUP BY CON1.OWNER, CON1.TABLE_NAME, CON1.CONSTRAINT_NAME, CON1.DELETE_RULE, CON1.STATUS, CON.TABLE_NAME, CON.CONSTRAINT_NAME, COL.POSITION, COL.COLUMN_NAME) GROUP BY OWNER_1, CONSTRAINT_NAME_1, TABLE_NAME_1, TABLE_NAME; ... and it contains the error of using DBA_CONSTRAINTS instead of ALL_CONSTRAINTS... Please pay attention to this: http://stackoverflow.com/questions/485581/generate-delete-statement-from-foreign-key-relationships-in-sql-2008/2677145#2677145 Another user has just written it in SQL SERVER 2008, anyone is able to convert to Oracle 10G PL/SQL? I am not able to... :-( This is the code written by another user in SQL SERVER 2008: DECLARE @COLUMN_NAME AS sysname DECLARE @TABLE_NAME AS sysname DECLARE @IDValue AS int SET @COLUMN_NAME = '<Your COLUMN_NAME here>' SET @TABLE_NAME = '<Your TABLE_NAME here>' SET @IDValue = 123456789 DECLARE @sql AS varchar(max) ; WITH RELATED_COLUMNS AS ( SELECT QUOTENAME(c.TABLE_SCHEMA) + '.' + QUOTENAME(c.TABLE_NAME) AS [OBJECT_NAME] ,c.COLUMN_NAME FROM PBANKDW.INFORMATION_SCHEMA.COLUMNS AS c WITH (NOLOCK) INNER JOIN PBANKDW.INFORMATION_SCHEMA.TABLES AS t WITH (NOLOCK) ON c.TABLE_CATALOG = t.TABLE_CATALOG AND c.TABLE_SCHEMA = t.TABLE_SCHEMA AND c.TABLE_NAME = t.TABLE_NAME AND t.TABLE_TYPE = 'BASE TABLE' INNER JOIN ( SELECT rc.CONSTRAINT_CATALOG ,rc.CONSTRAINT_SCHEMA ,lkc.TABLE_NAME ,lkc.COLUMN_NAME FROM PBANKDW.INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS rc WITH (NOLOCK) INNER JOIN PBANKDW.INFORMATION_SCHEMA.KEY_COLUMN_USAGE lkc WITH (NOLOCK) ON lkc.CONSTRAINT_CATALOG = rc.CONSTRAINT_CATALOG AND lkc.CONSTRAINT_SCHEMA = rc.CONSTRAINT_SCHEMA AND lkc.CONSTRAINT_NAME = rc.CONSTRAINT_NAME INNER JOIN PBANKDW.INFORMATION_SCHEMA.TABLE_CONSTRAINTS tc WITH (NOLOCK) ON rc.CONSTRAINT_CATALOG = tc.CONSTRAINT_CATALOG AND rc.CONSTRAINT_SCHEMA = tc.CONSTRAINT_SCHEMA AND rc.UNIQUE_CONSTRAINT_NAME = tc.CONSTRAINT_NAME INNER JOIN PBANKDW.INFORMATION_SCHEMA.KEY_COLUMN_USAGE rkc WITH (NOLOCK) ON rkc.CONSTRAINT_CATALOG = tc.CONSTRAINT_CATALOG AND rkc.CONSTRAINT_SCHEMA = tc.CONSTRAINT_SCHEMA AND rkc.CONSTRAINT_NAME = tc.CONSTRAINT_NAME WHERE rkc.COLUMN_NAME = @COLUMN_NAME AND rkc.TABLE_NAME = @TABLE_NAME ) AS j ON j.CONSTRAINT_CATALOG = c.TABLE_CATALOG AND j.CONSTRAINT_SCHEMA = c.TABLE_SCHEMA AND j.TABLE_NAME = c.TABLE_NAME AND j.COLUMN_NAME = c.COLUMN_NAME ) SELECT @sql = COALESCE(@sql, '') + 'DELETE FROM ' + [OBJECT_NAME] + ' WHERE ' + [COLUMN_NAME] + ' = ' + CONVERT(varchar, @IDValue) + CHAR(13) + CHAR(10) FROM RELATED_COLUMNS PRINT @sql Thank to Charles, this is the latest not working release of the software, I have added a parameter with the OWNER because the referential integrities propagate through about 5 other Oracle users (!!!): CREATE OR REPLACE PROCEDURE delete_cascade ( parent_table VARCHAR2, parent_table_owner VARCHAR2) IS cons_name VARCHAR2 (30); tab_name VARCHAR2 (30); tab_name_owner VARCHAR2 (30); parent_cons VARCHAR2 (30); parent_col VARCHAR2 (30); delete1 VARCHAR (500); delete2 VARCHAR (500); delete_command VARCHAR (4000); CURSOR cons_cursor IS SELECT constraint_name, r_constraint_name, table_name, constraint_type FROM all_constraints WHERE constraint_type = 'R' AND r_constraint_name IN (SELECT constraint_name FROM all_constraints WHERE constraint_type IN ('P', 'U') AND table_name = parent_table AND owner = parent_table_owner) AND delete_rule = 'NO ACTION'; CURSOR tabs_cursor IS SELECT DISTINCT table_name FROM all_cons_columns WHERE constraint_name = cons_name; CURSOR child_cols_cursor IS SELECT column_name, position FROM all_cons_columns WHERE constraint_name = cons_name AND table_name = tab_name; BEGIN FOR cons IN cons_cursor LOOP cons_name := cons.constraint_name; parent_cons := cons.r_constraint_name; SELECT DISTINCT table_name, owner INTO tab_name, tab_name_owner FROM all_cons_columns WHERE constraint_name = cons_name; delete_cascade (tab_name, tab_name_owner); delete_command := ''; delete1 := ''; delete2 := ''; FOR col IN child_cols_cursor LOOP SELECT DISTINCT column_name INTO parent_col FROM all_cons_columns WHERE constraint_name = parent_cons AND position = col.position; IF delete1 IS NULL THEN delete1 := col.column_name; ELSE delete1 := delete1 || ', ' || col.column_name; END IF; IF delete2 IS NULL THEN delete2 := parent_col; ELSE delete2 := delete2 || ', ' || parent_col; END IF; END LOOP; delete_command := 'delete from ' || tab_name_owner || '.' || tab_name || ' where (' || delete1 || ') in (select ' || delete2 || ' from ' || parent_table_owner || '.' || parent_table || ');'; INSERT INTO ris VALUES (SEQUENCE_COMANDI.NEXTVAL, delete_command); COMMIT; END LOOP; END; / In the cursor CONS_CURSOR I have added the condition: AND delete_rule = 'NO ACTION'; in order to avoid deletion in case of referential integrities with DELETE_RULE = 'CASCADE' or DELETE_RULE = 'SET NULL'. Now I have tried to turn from stored procedure to stored function, but the delete statements are not correct: CREATE OR REPLACE FUNCTION deletecascade ( parent_table VARCHAR2, parent_table_owner VARCHAR2) RETURN VARCHAR2 IS cons_name VARCHAR2 (30); tab_name VARCHAR2 (30); tab_name_owner VARCHAR2 (30); parent_cons VARCHAR2 (30); parent_col VARCHAR2 (30); delete1 VARCHAR (500); delete2 VARCHAR (500); delete_command VARCHAR (4000); AT_LEAST_ONE_ITERATION NUMBER DEFAULT 0; CURSOR cons_cursor IS SELECT constraint_name, r_constraint_name, table_name, constraint_type FROM all_constraints WHERE constraint_type = 'R' AND r_constraint_name IN (SELECT constraint_name FROM all_constraints WHERE constraint_type IN ('P', 'U') AND table_name = parent_table AND owner = parent_table_owner) AND delete_rule = 'NO ACTION'; CURSOR tabs_cursor IS SELECT DISTINCT table_name FROM all_cons_columns WHERE constraint_name = cons_name; CURSOR child_cols_cursor IS SELECT column_name, position FROM all_cons_columns WHERE constraint_name = cons_name AND table_name = tab_name; BEGIN FOR cons IN cons_cursor LOOP AT_LEAST_ONE_ITERATION := 1; cons_name := cons.constraint_name; parent_cons := cons.r_constraint_name; SELECT DISTINCT table_name, owner INTO tab_name, tab_name_owner FROM all_cons_columns WHERE constraint_name = cons_name; delete1 := ''; delete2 := ''; FOR col IN child_cols_cursor LOOP SELECT DISTINCT column_name INTO parent_col FROM all_cons_columns WHERE constraint_name = parent_cons AND position = col.position; IF delete1 IS NULL THEN delete1 := col.column_name; ELSE delete1 := delete1 || ', ' || col.column_name; END IF; IF delete2 IS NULL THEN delete2 := parent_col; ELSE delete2 := delete2 || ', ' || parent_col; END IF; END LOOP; delete_command := 'delete from ' || tab_name_owner || '.' || tab_name || ' where (' || delete1 || ') in (select ' || delete2 || ' from ' || parent_table_owner || '.' || parent_table || ');' || deletecascade (tab_name, tab_name_owner); INSERT INTO ris VALUES (SEQUENCE_COMANDI.NEXTVAL, delete_command); COMMIT; END LOOP; IF AT_LEAST_ONE_ITERATION = 1 THEN RETURN ' where COD_CHICKEN = V_CHICKEN AND COD_NATION = V_NATION;'; ELSE RETURN NULL; END IF; END; / Please assume that V_CHICKEN and V_NATION are the criteria to select the CHICKEN to delete from the root table: the condition is: "where COD_CHICKEN = V_CHICKEN AND COD_NATION = V_NATION" on the root table.

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  • How to type multiple characters on a mac with a single click?

    - by Yuval
    On a Windows machine, clicking and holding a keyboard key results in the key being types multiple times. For example, if I click and hold 'q' for a few seconds, I end up with the following: qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq Similarly, I can click and hold the Backspace key to delete multiple characters. On a Mac, it seems, clicking and holding a key for several seconds results in the key being types only once. To type it repeatedly, it is necessary to psychically click it multiple times. I'm unclear about whether that is a bug or a supposed-feature, but I am interested in replicating this functionality on a Mac. Any ideas? Thanks!

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  • Does multiple files in SQL Server when using RAID help reduce conflicts in growth and file-locking?

    - by Dr Giles M
    I've been reading around and get the impression that if you are using RAID then using multiple SQL Server files within a filegroup won't yeild any more improvements, and the benefits are purely administrative (if you started to run out of space or wanted to partition off data into managable chunks for backups/balancing the data around your big server room). However, being a reasonably savvy software person, it's not unthinkable to hypothesise that, even for smaller databases that SQL Server will perform growth and locking operations (for writes) on a LOGICAL file basis, so even if you are using RAID, it seems to make sense to have multiple files in a file group to balance I/O, or does the time taken to reconstruct the data from distributed filegroups outweigh the benefits of reduced locking? I'm also aware that the behaviour and benefits may be different for tables/indeces/log. Is there a good site that distinguishes the benefits of multiple files when RAID is already in place?

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  • How do I host multiple SSL websites on a single EC2 instance using Amazon Elastic Load Balancers?

    - by Developr
    If I have 3 separate websites which all require SSL (separate certificates) that I want to host on the same EC2 instance(s) across multiple availability zones so that we have the ability to scale and be highly available, how do I achieve this using ELBs in my Amazon VPC? Each site requires a separate IP address, so I have added multiple private IPs to the EC2 instance, but I am unsure how to bind the ELB to a certain IP on the instance. I was also able to setup multiple ELB pointing to the same instance, but again, I am not seeing any way to bind each ELB to a separate IP on the instance. If this is not possible, what is the best option? Run each site on a separate EC2 instance / ELB combo (expensive and harder to maintain) Give each site a separate public IP and use Route 53 to do the load balancing (seems like a hack) Use a different load balancer option such as HAProxy that should be able to work like a normal load balancer appliance. Please help!

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  • Multiple Memcached server /etc/init.d startup script that works ?

    - by p4guru
    I install memcached server via source and can get standard start up script installed for 1 memcached server instance, but trying several scripts via google, can't find one that works to manager auto start up on boot for multiple memcached server instances. I've tried both these scripts and both don't work, service memcached start just returns to command prompt with no memcached server instances started lullabot.com/articles/installing-memcached-redhat-or-centos addmoremem.blogspot.com/2010/09/running-multiple-instances-of-memcached.html However this bash script works but doesn't start up memcached instances at start up though ? #!/bin/sh case "$1" in start) /usr/local/bin/memcached -d -m 16 -p 11211 -u nobody /usr/local/bin/memcached -d -m 16 -p 11212 -u nobody ;; stop) killall memcached ;; esac OS: Centos 5.5 64bit Memcached = v1.4.5 Memcache = v2.2.5 Anyone can point me to a working /etc/init.d/ startup script to manage multiple memcached servers ? Thanks

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  • How to configure Nginx to serve a variety of back-ends via multiple FCGI processes?

    - by Ben Horton
    I've seen a lot of tutorials showing one how to set up PHP/Python/Perl/RoR on nginx via various FCGI processes. None of the tutorials that I found show one how to serve multiple FCGI services off one server. How would one configure the stable nginx (nginx-0.7.64) to serve multiple FCGI processes (one for each of the above languages)? Example addresses for each FCGI process are as follows: 127.0.0.1:8080 - PHP 127.0.0.1:8081 - Python 127.0.0.1:8082 - Perl 127.0.0.1:8083 - Ruby on Rails An example configuration file that shows one how to implement multiple FCGI's off one server is really what I need. Perhaps others will benefit as well.

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  • Does a single LACP channel over multiple switches increase redundancy?

    - by Sirch
    I am curious for opinions, findings, or evidence that having multiple interfaces bonded using LACP to ports in multiple switches can increase redundancy. Previously bonded interfaces have always been to a single switch, with a redundant channel to another port. Without getting into vendor specifics, my thought is that as this is a single LACP, the likelihood that an event or change could lead to a wide service outage. Without having the spare equipment or time to test this single channel over diverse switches, could anyone with a greater networking knowledge than myself, tell me if there a network side event that would bring down the network connectivity to a server that had created a bonded interface to two ports on separate switches? Does the use of bonded ethernet channels across multiple switches (that we are advised that we can use) from the server, provide both improved throughput (unquestionably), and improved redundancy (uncertain). Could/would network events such as switch failure, port migration, patching, recovery, etc, cause the channel for both server network interfaces to be unavailable? Thanks in advance.

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  • Multiple SSL domains on the same IP address and same port?

    - by John
    This is a Canonical Question about Hosting multiple SSL websites on the same IP. I was under the impression that each SSL Certificate required it's own unique IP Address/Port combination. But the answer to a previous question I posted is at odds with this claim. Using information from that Question, I was able to get multiple SSL certificates to work on the same IP address and on port 443. I am very confused as to why this works given the assumption above and reinforced by others that each SSL domain website on the same server requires its own IP/Port. I am suspicious that I did something wrong. Can multiple SSL Certificates be used this way?

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  • How SQL Server 2014 impacts Red Gate’s SQL Compare

    - by Michelle Taylor
    SQL Compare 10.7 successfully connects to SQL Server 2014, but it doesn’t yet cover the SQL Server 2014 features which would require us to make major changes to SQL Compare to support. In this post I’m going to talk about the SQL Server 2014 features we’ve already begun supporting, and which ones we’re working on for the next release of SQL Compare (v11). From SQL Compare’s perspective, the new memory-optimized table functionality (some might know it as ‘Hekaton’) has been the most important change. It can’t be described as its own object type, but the new functionality is split across two existing object types (three if you count indexes), as it also comes with native stored procedures and inline indexes. Along with connectivity support, the SQL Compare team has already implemented the first part of the puzzle – inline specification of indexes. These are essential for memory-optimized tables because it’s not possible to alter the memory optimized table’s structure, and so indexes can’t be added after the fact without dropping the table. Books Online  shows this in more detail in the table_index and column_index clauses of http://msdn.microsoft.com/en-us/library/ms174979(v=sql.120).aspx. SQL Compare 10.7 currently supports reading the new inline index specification from script folders and source control repositories, and will write out inline indexes where it’s necessary to do so (i.e. in UDDTs or when attempting to write projects compatible with the SSDT database project format). However, memory-optimized tables themselves are not yet supported in 10.7. The team is actively working on making them available in the v11 release with full support later in the year, and in a beta version before that. Fortunately, SQL Compare already has some ways of handling tables that have to be dropped and created rather than altered, which are being adapted to handle this new kind of table. Because it’s one of the largest new database engine features, there’s an equally large Books Online section on memory-optimized tables, but for us the most important parts of the documentation are the normal table features that are changed or unsupported and the new syntax found in the T-SQL reference pages. We are treating SQL Compare’s support of Natively Compiled Stored Procedures as a separate unit of work, which will be available in a subsequent beta and also feed into the v11 release. This new type of stored procedure is designed to work with memory-optimized tables to maintain the performance improvements gained by them – but you can still also access memory-optimized tables from normal stored procedures and ad-hoc queries. To us, they’re essentially a limited-syntax stored procedure with a few extra options in the create statement, embodied in the updated CREATE PROCEDURE documentation and with the detailed limitations. They should be easier to handle than memory-optimized tables simply because the handling of stored procedures is less sensitive to dropping the object than the handling of tables. However, both share an incompatibility with DDL triggers and Event Notifications which mean we’ll need to temporarily disable these during the specific deployment operations that involve them – don’t worry, we’ll supply a warning if this is the case so that you can check your auditing arrangements can handle the situation. There are also a handful of other improvements in SQL Server 2014 which affect SQL Compare and SQL Data Compare that are not connected to memory optimized tables. The largest of these are the improvements to columnstore indexes, with the capability to create clustered columnstore indexes and update columnstore tables through them – for more detail, take a look at the new syntax reference. There’s also a new index option for better compression of columnstores (COLUMNSTORE_ARCHIVE) and a new statistics option for incremental per-partition statistics, plus the 90 compatibility level is being retired. We’re planning to finish up these small clean-up features last, and be ready to release SQL Compare 11 with full SQL 2014 support early in Q3 this year. For a more thorough overview of what’s new in SQL Server 2014, Books Online’s What’s New section is a good place to start (although almost all the changes in this version are in the Database Engine).

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  • can 'Percona MySQL Data Recovery' be used to recover dropped tables if the datadir filesystem is mounted as /

    - by Tom Geee
    according to Percona: Unmount the filesystem or make it read-only if... You have filesystem corruption OR You have dropped tables in innodb_file_per_table format If I have innodb_file_per_table enabled, and accidently dropped a table, while the datadir is mounted as within the / partition , can data still be recovered? Obviously you can't work with an unmounted root filesystem. Our VPS host has a defaulted filesystem table which we cannot customize. I was wondering in case of any future scenario. edit: would mounting the / filesystem through NFS onto another system as read-only be a workaround? TIA.

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  • Best way to handle multiple tables to replace one big table in Rails? (e.g. 'Books1', 'Books2', etc.

    - by mikep
    Hello, I've decided to use multiple tables for an entity (e.g. Books1, Books2, Books3, etc.), instead of just one main table which could end up having a lot of rows (e.g. just Books). I'm doing this to try and to avoid a potential future performance drop that could come with having too many rows in one table. With that, I'm looking for a good way to handle this in Rails, mainly by trying to avoid loading a bunch of unused associations. (I know that I could use a partition for this, but, for now, I've decided to go the 'multiple tables' route.) Each user has their books placed into a specific table. The actual book table is chosen when the user is created, and all of their books go into the same table. I'm going to split the adds across the tables. The goal is to try and keep each table pretty much even -- but that's a different issue. One thing I don't particularly want to have is a bunch of unused associations in the User class. Right now, it looks like I'd have to do the following: class User < ActiveRecord::Base has_many :books1, :books2, :books3, :books4, :books5 end class Books1 < ActiveRecord::Base belongs_to :user end class Books2 < ActiveRecord::Base belongs_to :user end class Books3 < ActiveRecord::Base belongs_to :user end I'm assuming that the main performance hit would come in terms of memory and possibly some method call overhead for each User object, since it has to load all of those associations, which in turn creates all of those nice, dynamic model accessor methods like User.find_by_. But for each specific user, only one of the book tables would be usable/applicable, since all of a user's books are stored in the same table. So, only one of the associations would be in use at any time and any other has_many :bookX association that was loaded would be a waste. For example, with a user.id of 2, I'd only need books3.find_by_author('Author'), but the way I'm thinking of setting this up, I'd still have access to Books1..n. I don't really know Ruby/Rails does internally with all of those has_many associations though, so maybe it's not so bad. But right now I'm thinking that it's really wasteful, and that there may just be a better, more efficient way of doing this. So, a few questions: 1) Is there's some sort of special Ruby/Rails methodology that could be applied to this 'multiple tables to represent one entity' scheme? Are there any 'best practices' for this? 2) Is it really bad to have so many unused has_many associations for each object? Is there a better way to do this? 3) Does anyone have any advice on how to abstract the fact that there's multiple book tables behind a single books model/class? For example, so I can call books.find_by_author('Author') instead of books3.find_by_author('Author'). Thank you!

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  • RDLC: Is there a way to print multiple tables without SubReports?

    - by Eduardo Molteni
    I'm generating the RDLC XML schema and showing the report in the ReportViewer control. No problems there. Now, I want a report with 2 tables, with 2 differents dataset. Something like this gets generated: <Body> <ReportItems> <Table Name="Table1"> .... </Table> <Table Name="Table2"> .... </Table> </ReportItems> </Body> But, when printed, both tables start from the top, printing on table over the other (not nice) Is there a way to tell that Table2 should start after Table1? Update: I've tried with List with a fake DataSource, but it does not work.

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  • In MySQL, what is the most effective query design for joining large tables with many to many relatio

    - by lighthouse65
    In our application, we collect data on automotive engine performance -- basically source data on engine performance based on the engine type, the vehicle running it and the engine design. Currently, the basis for new row inserts is an engine on-off period; we monitor performance variables based on a change in engine state from active to inactive and vice versa. The related engineState table looks like this: +---------+-----------+---------------+---------------------+---------------------+-----------------+ | vehicle | engine | engine_state | state_start_time | state_end_time | engine_variable | +---------+-----------+---------------+---------------------+---------------------+-----------------+ | 080025 | E01 | active | 2008-01-24 16:19:15 | 2008-01-24 16:24:45 | 720 | | 080028 | E02 | inactive | 2008-01-24 16:19:25 | 2008-01-24 16:22:17 | 304 | +---------+-----------+---------------+---------------------+---------------------+-----------------+ For a specific analysis, we would like to analyze table content based on a row granularity of minutes, rather than the current basis of active / inactive engine state. For this, we are thinking of creating a simple productionMinute table with a row for each minute in the period we are analyzing and joining the productionMinute and engineEvent tables on the date-time columns in each table. So if our period of analysis is from 2009-12-01 to 2010-02-28, we would create a new table with 129,600 rows, one for each minute of each day for that three-month period. The first few rows of the productionMinute table: +---------------------+ | production_minute | +---------------------+ | 2009-12-01 00:00 | | 2009-12-01 00:01 | | 2009-12-01 00:02 | | 2009-12-01 00:03 | +---------------------+ The join between the tables would be engineState AS es LEFT JOIN productionMinute AS pm ON es.state_start_time <= pm.production_minute AND pm.production_minute <= es.event_end_time. This join, however, brings up multiple environmental issues: The engineState table has 5 million rows and the productionMinute table has 130,000 rows When an engineState row spans more than one minute (i.e. the difference between es.state_start_time and es.state_end_time is greater than one minute), as is the case in the example above, there are multiple productionMinute table rows that join to a single engineState table row When there is more than one engine in operation during any given minute, also as per the example above, multiple engineState table rows join to a single productionMinute row In testing our logic and using only a small table extract (one day rather than 3 months, for the productionMinute table) the query takes over an hour to generate. In researching this item in order to improve performance so that it would be feasible to query three months of data, our thoughts were to create a temporary table from the engineEvent one, eliminating any table data that is not critical for the analysis, and joining the temporary table to the productionMinute table. We are also planning on experimenting with different joins -- specifically an inner join -- to see if that would improve performance. What is the best query design for joining tables with the many:many relationship between the join predicates as outlined above? What is the best join type (left / right, inner)?

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  • What tools exist for generating "ASCII Tables", if any?

    - by Billy ONeal
    Consider a block like the following: +-----------------------------------+--------------------------+ | In Baseline | Not in Baseline | +---------------+===================================+==========================+ | In Parent # Do Not Report | Mark ACE as AlwaysReport | +---------------+-----------------------------------+--------------------------+ | Not In Parent # Iff parent depth > baseline depth | Report Always | +---------------+-----------------------------------+--------------------------+ I have seen tables like this used quite frequently. For instance, in Requests for Comments (RFC) documents, the standard format of the document is the text format. Another common case is embedding a small table like this into comments of source code. Are there tools which can take a quick and dirty representation of this in Excel, or possibly some textual format, and format it as a table like this?

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  • Is it Possible to Query Multiple Databases with WCF Data Services?

    - by Mas
    I have data being inserted into multiple databases with the same schema. The multiple databases exist for performance reasons. I need to create a WCF service that a client can use to query the databases. However from the client's point of view, there is only 1 database. By this I mean when a client performs a query, it should query all databases and return the combined results. I also need to provide the flexibility for the client to define its own queries. Therefore I am looking into WCF Data Services, which provides the very nice functionality for client specified queries. So far, it seems that a DataService can only make a query to a single database. I found no override that would allow me to dispatch queries to multiple databases. Does anyone know if it is possible for a WCF Data Service to query against multiple databases with the same schema?

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  • How would you audit ASP.NET Membership tables, while recording what user made the changes?

    - by Pete
    Using a trigger-based approach to audit logging, I am recording the history of changes made to tables in the database. The approach I'm using (with a static sql server login) to record which user made the change involves running a stored procedure at the outset of each database connection. The triggers use this username when recording the audit rows. (The triggers are provided by the product OmniAudit.) However, the ASP.NET Membership tables are accessed primarily through the Membership API. I need to pass in the current user's identity when the Membership API opens its database connection. I tried subclassing MembershipProvider but I cannot access the underlying database connection. It seems like this would be a common problem. Does anyone know of any hooks we can access when the ASP.NET Membership makes its database connection?

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  • how to calculate a bill from several tables on mysql?

    - by Audel
    I'm using mysql to create an hotel booking system, but i am struggling a little bit to calculate the final bill. I need a SELECT command to get data from several tables and make some calculations. Basically I just need to get the 'night cost' from a table called 'room_types'. Then, use DATEDIFF function to get the difference of days between the 'checkin' and 'checkout' columns in the table 'room_booking' and multiply the difference with the night cost and display the total. These are the tables I would be using: are room_booking, room_types, booking, and room. One booking may have several room bookings, so Im looking for a table that looks something like this: +------------+------------+---------------+------------------+ | bookingid | Room price | nights stayed | total room price | +------------+------------+---------------+------------------+ | B001 | 30.00 | 4 | 120.00 | +------------+------------+---------------+------------------+ | B001 | 40.00 | 3 | 120.00 | +------------+------------+---------------+------------------+ booking id comes from table 'booking' room price from 'room_types', 'nights stayed' is calculated from the table room_booking, using the datediff command between checkin and checkout . I hope i was clear

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  • How to define cell width for 2 HTML tables with different column counts?

    - by DaveDev
    If I have 2 tables: <table id="Table1"> <tr> <td></td><td></td><td></td> </tr> </table> <table id="Table2"> <tr> <td></td><td></td><td></td><td></td> </tr> </table> The first has 3 columns, the second has 4 columns. How can I define a style to represent both tables when I want Table1's cell width to be 1/3 the width of the full table, and Table2's cells are 1/4 the width of the table?

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  • Selenium/NUnit run one test on multiple IP addresses.

    - by Matt Clarkson
    I have a test suite DLL written in C# that uses Selenium.This is then loaded into NUnit and tests can be performed on our embedded web server boards. Does anyone know how to run a NUnit Selenium test on multiple IPs in multiple browsers? I have tried creating multiple DefaultSelenium classes but they point to the same Internet Explorer window. I need multiple instances of the Selenium RC controlling individual Internet Explorer windows. Have been looking a lot on the Selenium User Group and in various documentation but can find a definitive answer. Cheers, Matt

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  • How to play the same Sound multiple times with overlap, using OpenAL or Finch?

    - by mystify
    Finch uses OpenAL. However, when I have an instance of Sound, and say -play, the sound plays. When I call -play multiple times one after another in a fast paced way, every -play makes the current sound playback of that sound stop and restart it. That's not what I want. Would I have to create multiple sources or buffers to get that working? Or would I just instantiate multiple Sounds with the same file?

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  • To Create a Search, with values from multiple selection element?

    - by Harish
    I am working in PHP(with Symfony Framework) and i want to create a search based on multiple values selected from multiple selection element, i.e there will be multiple selection dropdown elements for like countries, cities, age etc.. and the values from them will query a data table and give the desired search output. (all values are not mandatory, will work with atleast one value). the idea will also do..

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