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  • How to approach this SQL query

    - by Kim
    I have data related as follows: A table of Houses A table of Boxes (with an FK back into Houses) A table of Things_in_boxes (with an FK back to Boxes) A table of Owners (with an FK back into Houses) In a nutshell, a House has many Boxes, and each Box has many Things in it. In addition, each House has many Owners. If I know two Owners (say Peter and Paul), how can I list all the Things that are in the Boxes that are in the Houses owned by these guys? Also, I'd like to master this SQL stuff. Can anyone recommend a good book/resource? (I'm using MySQL). Thanks!

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  • One to One relationship in MySQL

    - by Botto
    I'm trying to make a one to one relationship in a MySQL DB. I'm using the InnoDB engine and the basic table looks like this: CREATE TABLE `foo` ( `fooID` INT(11) NOT NULL PRIMARY KEY AUTO_INCREMENT, `name` TEXT NOT NULL ) CREATE TABLE `bar` ( `barName` VARCHAR(100) NOT NULL, `fooID` INT(11) NOT NULL PRIMARY KEY, CONSTRAINT `contact` FOREIGN KEY (`fooID`) REFERENCES `foo`(`fooID`) ) Now once I have set up these I alter the foo table so that the fooID also becomes a foreign key to the fooID in bar. The only issue I am facing with this is that there will be a integrity issue when I try to insert into either. I would like some help, thanks.

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  • .before method adds unexpected close tags

    - by timkl
    I have a table in my markup on which I want to add some divs before and efter like this: <div class="widebox"> <div class="widebox-header">Opret/rediger bruger</div> <div class="widebox-middle"> <table id="Table3"></table> </div> <div class="widebox-bottom"></div> </div> I'm trying to do this with jQuery, like this: $('#Table3').before('<div class="widebox"><div class="widebox-header">Opret/rediger bruger</div><div class="widebox-middle">'); $('#Table3').after('</div><div class="widebox-bottom"></div></div>'); However this is what renders out, the method seems to close my opening divs: <div class="widebox"> <div class="widebox-header">Opret/rediger bruger</div> <div class="widebox-middle"></div></div><!-- unexpected close divs --> <table id="Table3"></table> <div class="widebox-bottom"></div> Anyone know what could be causing this?

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  • SQL to concatenate column values from multiple rows

    - by HonorGod
    Would it be possible to construct SQL to concatenate column values from multiple rows? The following is an example: Table A PID A B C Table B PID SEQ Desc A 1 Have A 2 a nice A 3 day. B 1 Nice Work. C 1 Yes C 2 we can C 3 do C 4 this work! Output of the SQL should be - PID Desc A Have a nice day. B Nice Work. C Yes we can do this work! So basically the Desc column for out put table is a concatenation of the SEQ values from Table B? Any help with the SQL?

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  • Mysql Removal of primary key

    - by marionmaiden
    Hello, I've removed the primary key of one table of my MySQL database, but now, when I use the MySQL Administrator and try to edit the data of this table, it doesn't allow me to do this. The button edit that appears in the bottom of the table keeps visible, but unable to click.

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  • Adding a Line Break in mySQL INSERT INTO text

    - by james
    Hi Could someone tell me how to add a new line in a text that i enter in a mySql table. I tried using the '\n in the line i entered with INSERT INTO statement but '\n is shown as it is. Actually i have created a table in Ms Access with some data. Ms Access adds new line with '\n. I am converting Ms Access table data into mySql . But when i convert, the '\n is ignored and all the text is shown in one single line when i display it from mySql table on a php form. Can anyone tell me how mySQL can add a new line in a text ? Awaiting response Thanks !!

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  • Calculating and saving space in Postgresql

    - by punkish
    I have a table in Pg like so CREATE TABLE t ( a BIGSERIAL NOT NULL, -- 8 b b SMALLINT, -- 2 b c SMALLINT, -- 2 b d REAL, -- 4 b e REAL, -- 4 b f REAL, -- 4 b g INTEGER, -- 4 b h REAL, -- 4 b i REAL, -- 4 b j SMALLINT, -- 2 b k INTEGER, -- 4 b l INTEGER, -- 4 b m REAL, -- 4 b CONSTRAINT a_pkey PRIMARY KEY (a) ) The above adds up to 50 bytes per row. My experience is that I need another 40% to 50% for system overhead, without even any user-created indexes to the above. So, about 75 bytes per row. I will have many, many rows in the table, potentially upward of 145 billion rows, so the table is going to be pushing 13-14 Terabytes. What tricks, if any, could I use to compact this table? My possible ideas below -- Convert the REAL values to INTEGERs. If they can stored as SMALLINT, that is a saving of 2 bytes per field. Convert the columns b .. m into an array. I don't need to search on those columns, but I do need to be able to return one column's value at a time. So, if I need column g, I could do something like SELECT a, arr[5] FROM t; Would I save space with the array option? Would there be a speed penalty? Any other ideas?

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  • LinqToSQL: Not possible to update PrimaryKey?

    - by Zuhaib
    I have a simple table (lets call it Table1) that has a NVARCHAR field as the PK. Table1 has no association with any other tables. When I update Table1's PK column using LinqToSQL it fails. If I update other column it succeeds. I could delete this row and insert new one in Table1, but I don't want to. There is a transaction table which has Table1's PK column as a column. When the PK of Table1 is changed I want no effect in the transaction table. But when the row from Table1 is deleted, I want the transaction rows to be deleted. The cascading is done via Trigger. As there is not association between these two tables, if I update the PK column of Table1 using normal SQL, it works and there is no effect on the transaction table as expected. When I delete the row the trigger deletes the rows from transaction table. For this reason I can't delete and then add new row in Table1. So what can be done to successfully update the PrimaryKey of the Table1?

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  • MEMORY(HEAP) vs. InnoDB in a Read and Write Environment

    - by Johannes
    I want to program a real-time application using MySQL. It needs a small table (less than 10000 rows) that will be under heavy read (scan) and write (update and some insert/delete) load. I am really speaking of 10000 updates or selects per second. These statements will be executed on only a few (less than 10) open mysql connections. The table is small and does not contain any data that needs to be stored on disk. So I ask which is faster: InnoDB or MEMORY (HEAP)? My thoughts are: Both engines will probably serve SELECTs directly from memory, as even InnoDB will cache the whole table. What about the UPDATEs? (innodb_flush_log_at_trx_commit?) My main concern is the locking behavior: InnoDB row lock vs. MEMORY table lock. Will this present the bottleneck in the MEMORY implementation? Thanks for your thoughts!

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  • JQuery tablesorter - Second click on column header doesn't resort

    - by Jonathan
    I'm using tablesorter in on a table I added to a view in django's admin (although I'm not sure this is relevant). I'm extending the html's header: {% block extrahead %} <script type="text/javascript" src="http://code.jquery.com/jquery-1.4.2.js"></script> <script type="text/javascript" src="http://mysite.com/media/tablesorter/jquery.tablesorter.js"></script> <script type="text/javascript"> $(document).ready(function() { $("#myTable").tablesorter(); } ); </script> {% endblock %} When I click on a column header, it sorts the table using this column in descending order - that's ok. When I click the same column header a second time - it does not reorder to ascending order. What's wrong with it? the table's html looks like: <table id="myTable" border="1"> <thead> <tr> <th>column_name_1</th> <th>column_name_2</th> <th>column_name_3</th> </tr> </thead> <tbody> {% for item in extra.items %} <tr> <td>{{ item.0|safe }} </td> <td>{{ item.1|safe }} </td> <td>{{ item.2|safe }} </td> </tr> {% endfor %} </tbody> </table>

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  • Oracle Unique Indexes

    - by Melvin
    I was creating a new table today in 10g when I noticed an interesting behavior. Here is an example of what I did: CREATE TABLE test_table ( field_1 INTEGER PRIMARY KEY ); Oracle will by default, create a non-null unique index for the primary key. I double checked this. After a quick check, I find a unique index name SYS_C0065645. Everything is working as expected so far. Now I did this: CREATE TABLE test_table ( field_1 INTEGER, CONSTRAINT pk_test_table PRIMARY KEY (field_1) USING INDEX (CREATE INDEX idx_test_table_00 ON test_table (field_1))); After describing my newly created index idx_test_table_00, I see that it is non-unique. I tried to insert duplicate data into the table and was stopped by the primary key constraint, proving that the functionality has not been affected. It seems strange to me that Oracle would allow a non-unique index to be used for a primary key constraint. Why is this allowed?

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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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  • How to make columns as wide as the widest entry?

    - by Helper Method
    For a gcc cheatsheet I'm writing, I want to create a table which should describe how gcc interprets different file endings. The table I created so far is defined as follows: |====================================================================== |.c |C source code which must be preprocessed. |.i |C source code which should not be preprocessed. |.h |C header file to be turned into a precompiled header. |.s |Assembler code. |other | An object file to be fed straight into linking. Any file name with no recognized suffix is treated this way. |====================================================================== The problem I have is that the table spans the total page width, but what I want is that each column only is as wide as it's widest entry, and that the table will span only as much witdh as it needs.

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  • Merge computed data from two tables back into one of them

    - by Tyler McHenry
    I have the following situation (as a reduced example). Two tables, Measures1 and Measures2, each of which store an ID, a Weight in grams, and optionally a Volume in fluid onces. (In reality, Measures1 has a good deal of other data that is irrelevant here) Contents of Measures1: +----+----------+--------+ | ID | Weight | Volume | +----+----------+--------+ | 1 | 100.0000 | NULL | | 2 | 200.0000 | NULL | | 3 | 150.0000 | NULL | | 4 | 325.0000 | NULL | +----+----------+--------+ Contents of Measures2: +----+----------+----------+ | ID | Weight | Volume | +----+----------+----------+ | 1 | 75.0000 | 10.0000 | | 2 | 400.0000 | 64.0000 | | 3 | 100.0000 | 22.0000 | | 4 | 500.0000 | 100.0000 | +----+----------+----------+ These tables describe equivalent weights and volumes of a substance. E.g. 10 fluid ounces of substance 1 weighs 75 grams. The IDs are related: ID 1 in Measures1 is the same substance as ID 1 in Measures2. What I want to do is fill in the NULL volumes in Measures1 using the information in Measures2, but keeping the weights from Measures1 (then, ultimately, I can drop the Measures2 table, as it will be redundant). For the sake of simplicity, assume that all volumes in Measures1 are NULL and all volumes in Measures2 are not. I can compute the volumes I want to fill in with the following query: SELECT Measures1.ID, Measures1.Weight, (Measures2.Volume * (Measures1.Weight / Measures2.Weight)) AS DesiredVolume FROM Measures1 JOIN Measures2 ON Measures1.ID = Measures2.ID; Producing: +----+----------+-----------------+ | ID | Weight | DesiredVolume | +----+----------+-----------------+ | 4 | 325.0000 | 65.000000000000 | | 3 | 150.0000 | 33.000000000000 | | 2 | 200.0000 | 32.000000000000 | | 1 | 100.0000 | 13.333333333333 | +----+----------+-----------------+ But I am at a loss for how to actually insert these computed values into the Measures1 table. Preferably, I would like to be able to do it with a single query, rather than writing a script or stored procedure that iterates through every ID in Measures1. But even then I am worried that this might not be possible because the MySQL documentation says that you can't use a table in an UPDATE query and a SELECT subquery at the same time, and I think any solution would need to do that. I know that one workaround might be to create a new table with the results of the above query (also selecting all of the other non-Volume fields in Measures1) and then drop both tables and replace Measures1 with the newly-created table, but I was wondering if there was any better way to do it that I am missing.

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  • MySQL select two tables at the same time...

    - by Jerry
    Hi all I have two tables and want to make a query. I tried to get team AA and team BB's image base on table A. I used: SELECT tableA.team1, tableA.team2, tableB.team, tableB.image, FROM tableA LEFT JOIN tableB ON tableA.team1=tableB.team The result only display imageA on the column. Are there any ways to select imageA and image B without using the second query? I appreciate any helps! Thanks a lot! My table structure are: table A team1 team2 ------------ AA BB table B team image ------------- AA imagaA BB imageB

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  • Is it possible to keep mysql migration running without keeping connection open?

    - by taw
    ALTER TABLE can easily take a few days - and during this time there's a non-negligible chance of connection getting terminated due to network problems. Is it possible to start ALTER TABLE (or CREATE TABLE ... SELECT ...; or some other very long running query) and leave it running without keeping connection open all the time? (the obvious solution of screen + console mysql client won't easily work as there's no ssh running on that server, only mysqld).

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  • How do I check for the existence of an external file with XSL?

    - by LOlliffe
    I've found a lot of examples that reference Java and C for this, but how do I, or can I, check for the existence of an external file with XSL. First, I realize that this is only a snippet, but it's part of a huge stylesheet, so I'm hoping it's enough to show my issue. <!-- Use this template for Received SMSs --> <xsl:template name="ReceivedSMS"> <!-- Set/Declare "SMSname" variable (local, evaluates per instance) --> <xsl:variable name="SMSname"> <xsl:value-of select=" following-sibling::Name"/> </xsl:variable> <fo:table font-family="Arial Unicode MS" font-size="8pt" text-align="start"> <fo:table-column column-width=".75in"/> <fo:table-column column-width="6.75in"/> <fo:table-body> <fo:table-row> <!-- Cell contains "speakers" icon --> <fo:table-cell display-align="after"> <fo:block text-align="start"> <fo:external-graphic src="../images/{$SMSname}.jpg" content-height="0.6in"/> What I'd like to do, is put in an "if" statement, surronding the {$SMSname}.jpg line. That is: <fo:block text-align="start"> <xsl:if test="exists( the external file {$SMSname}.jpg)"> <fo:external-graphic src="../images/{$SMSname}.jpg" content-height="0.6in"/> </xsl:if> <xsl:if test="not(exists( the external file {$SMSname}.jpg))"> <fo:external-graphic src="../images/unknown.jpg" content-height="0.6in"/> </xsl:if> </fo:block> Because of "grouping", etc., I'm using XSLT 2.0. I hope that this is something that can be done. I hope even more that it's something simple. As always, thanks in advance for any help. LO

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  • Using ROWLOCK in an INSERT statement (SQL Server)

    - by RPS
    Would it be wise to use ROWLOCK on an insert statement that is copying large amounts of data and inserting it into the same table? Ex) INSERT INTO TABLE with (rowlock) (id, name) SELECT newid, name FROM TABLE with (nolock) WHERE id = 1 Does anybody have recommendations on how to improve this statement, as I see when SQL Server gets busy it will end in Timeout Query returned for SQL Server.

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  • Best practice how to store HTML in a database column

    - by tbrandao
    I have an application that modifies a table dynamically, think spreadsheet), then upon saving the form (which the table is part of) ,I store that changed table (with user modifications) in a database column named html_Spreadhseet,along with the rest of the form data. right now I'm just storing the html in a plain text format with basic escaping of characters... I'm aware that this could be stored as a separate file, the source table (html_workseeet) already is. But from a data handling perspective its easier to save the changed html table to and from a column so as to avoid having to come up with a file management strategy (which folder will this live in, now must include folder in backups, security issues now need to apply to files, how to sync db security with file system etc.), so to minimize these issues I'm only storing the ... part in the database column. My question is should I gzip the HTML , maybe use JSON, or some other format to easily store and retrieve the HTML from the database column, what is the best practice to store HTML content in a datbase? Or just store it as I currently am as an escaped text column?

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  • Check value at insert

    - by ThreeFingerMark
    Hello, i have this three tables. Table: Item Columns: ItemID, Title, Content, NoChange (Date) Table: Tag Columns: TagID, Title Table: ItemTag Columns: ItemID, TagID In the Item Table is a Field with NoChange, if this field = true no Tag is allowed to insert a ItemTag value with this ItemID. How can i check this in the insert? For Updates i have this Statement: UPDATE ItemTag SET TagID = ? where ItemID = ? AND TagID = ? AND exists ( select ItemID from Item where ItemID = ? AND NoChange is null)"); Thank you.

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  • access values of controls dynamically created on postback

    - by userk
    Hi, My problem is: I've got a table, dynamically created, fill with a lot of dropdownlists witches IDs are dynamically created. When a button is pressed, I need to scan all controls in the table and save their value. But after the postback I can't no longer access to the table, and I've no idea how can I get those values... Thanks!

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  • Calculate actual time from different timezones in php

    - by Thinker
    Hai, I would like to calculate actual time from different timezones. I have two mysql tables 1.Timezone table: This table contians two fields (offset value, country name) values are ( -12:00, Eniwetok, Kwajalein) (-11:00, Midway Island, Samoa).... so on 2.My employee table This table contains the employees details with two field names (created_on, timezone) and the values are (current timestamp, -11:00) (current timestamp, -12:00)..... so on Now, If my employee logged in to my system, i want to display the time according to their timezones values from tables. Basically if my Current timestamp is :2010-05-10 15:41:39 offset values is: +5:30 my result should be : 10 May 2010 3:41pm the same for different offset values for the same current timestamp. I believe i explained the issue correctly, if you want any information, please ask me.

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  • Need help tuning a SQL statement

    - by jeffself
    I've got a table that has two fields (custno and custno2) that need to be searched from a query. I didn't design this table, so don't scream at me. :-) I need to find all records where either the custno or custno2 matches the value returned from a query on the same table based on a titleno. In other words, the user types in 1234 for the titleno. My query searches the table to find the custno associated with the titleno. It also looks for the custno2 for that titleno. Then it needs to do a search on the same table for all other records that have either the custno or custno2 returned in the previous search in the custno or custno2 fields for those other records. Here is what I've come up with: SELECT BILLYR, BILLNO, TITLENO, VINID, TAXPAID, DUEDATE, DATEPIF, PROPDESC FROM TRCDBA.BILLSPAID WHERE CUSTNO IN (select custno from trcdba.billspaid where titleno = '1234' union select custno2 from trcdba.billspaid where titleno = '1234' and custno2 != '') OR CUSTNO2 IN (select custno from trcdba.billspaid where titleno = '1234' union select custno2 from trcdba.billspaid where titleno = '1234' and custno2 != '') The query takes about 5-10 seconds to return data. Can it be rewritten to work faster?

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