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• Is it possible to use SqlGeography with Linq to Sql?

  - by cofiem

  I've been having quite a few problems trying to use Microsoft.SqlServer.Types.SqlGeography. I know full well that support for this in Ling to Sql is not great. I've tried numerous ways, beginning with what would the expected way (Database type of geography, CLR type of SqlGeography). This produces the NotSupportedException, which is widely discussed via blogs. I've then gone down the path of treating the geography column as a varbinary(max), as geography is a UDT stored as binary. This seems to work fine (with some binary reading and writing extension methods). However, I'm now running into a rather obscure issue, which does not seem to have happened to many other people. System.InvalidCastException: Unable to cast object of type 'Microsoft.SqlServer.Types.SqlGeography' to type 'System.Byte[]'. This error is thrown from an ObjectMaterializer when iterating through a query. It seems to only occur when the tables containing geography columns are included in a query implicitly (ie. using the EntityRef<> properties to do joins). System.Data.Linq.SqlClient.ObjectReaderCompiler.ObjectReader`2.MoveNext() My question: If I'm retrieving the geography column as varbinary(max), I might expect the reverse error: can't cast byte[] to SqlGeography. That I would understand. This I don't. I do have some properies on the partial LINQ to SQL classes that hide the binary conversion... could those be the issue? Any help appreciated, and I know there's probably not enough information.

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• SQL: Join multiple tables and get a grouped sum

  - by Scienceprodigy

  I have a database with 3 tables that have related data. One table has transactions, and the other two relate to transaction categories. Basically it's financial data, so each transaction has a category (i.e. "gasoline" for a gas purchase transaction). A short version of my Transactions table looks like this- Transactions Table: ________________________________ | ID | Type | Amount | Category | --------------------------------- I also have two more tables relating a category to a categories parent. So basically, every Category entry in the Transactions Table belongs to a parent category (i.e. "gasoline" would belong to say "Automotive Expenses"). For categories, and their parent, I have two tables - Category Children: ____________________________________________ | ID | Parent Category ID | Child Category | -------------------------------------------- Category Parent: ________________________ | ID | Parent Category | ------------------------ What I'm trying to do is query the database and have it return a total spending by parent category. To get "spending" the Type of transactions must be "Debit". I tried the following statement: SELECT category_parents.parent_category, SUM(amount) AS totals FROM (transactions INNER JOIN category_children ON transactions.category = 'category_children.child_category') INNER JOIN category_parents ON category_children.parent_category_id = category_parents._id WHERE trans_type = 'Debit' GROUP BY parent_category ORDER BY totals DESC but it gives me the following exception: 12-31 13:51:21.515: ERROR/Exception on query(4403): android.database.sqlite.SQLiteException: no such column: category_children.parent_category_id: , while compiling: SELECT category_parents.parent_category, SUM(amount) AS totals FROM (transactions INNER JOIN category_children ON transactions.category='category_children.child_category') INNER JOIN category_parents ON category_children.parent_category_id=category_parents._id where trans_type='Debit' group by parent_category order by totals desc Any help is appreciated. (EXTRA CREDIT: I also need to make another statement to do spending by child category, given the parent category)

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• [XPATH] Retrieve specific preceding sibling nodes attributes

  - by Matthieu BROUILLARD

  Is there an XPath way of recovering directly one specific attribute of preceding sibling nodes of an XML node using an XPath query? In the following example, I would like to retrieve the values of the alt attribute of each img nodes that precede the div element marked with the id=marker. <content> <img alt="1" src="file.gif" /> <img alt="2" src="file.gif" /> <img alt="3" src="file.gif" /> <img alt="4" src="file.gif" /> <div id='marker'></div> </content> For this example, I want to retrieve the values 1 2 3 4. I use the following XPath query //div[@id='marker']/preceding-sibling::img in order to retrieve the node list I want <img alt="1" src="file.gif"/> <img alt="2" src="file.gif"/> <img alt="3" src="file.gif"/> <img alt="4" src="file.gif"/> As it is a node list I can then iterate on the nodes to retrieve the attribute value I am looking for, but is there an XPath way of doing it? I would have expected to be able to write something like: //div[@id='marker']/preceding-sibling::img@alt or //div[@id='marker']/preceding-sibling@alt::img but I don't even know if it is possible once you have used an XPath Axe like preceding-sibling.

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• What's the best way to select max over multiple fields in SQL?

  - by allyourcode

  The I kind of want to do is select max(f1, f2, f3). I know this doesn't work, but I think what I want should be pretty clear (see update 1). I was thinking of doing select max(concat(f1, '--', f2 ...)), but this has various disadvantages. In particular, doing concat will probably slow things down. What's the best way to get what I want? update 1: The answers I've gotten so far aren't what I'm after. max works over a set of records, but it compares them using only one value; I want max to consider several values, just like the way order by can consider several values. update 2: Suppose I have the following table: id class_name order_by1 order_by_2 1 a 0 0 2 a 0 1 3 b 1 0 4 b 0 9 I want a query that will group the records by class_name. Then, within each "class", select the record that would come first if you ordered by order_by1 ascending then order_by2 ascending. The result set would consist of records 2 and 3. In my magical query language, it would look something like this: select max(* order by order_by1 ASC, order_by2 ASC) from table group by class_name

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• php fuel 42000 error

  - by ryanc1256

  I don't get whats wrong. So this is the full error I get... Fuel\Core\Database_Exception [ 42000 ]: SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'to, from, message, checked) VALUES ('1', 'freddy', 'bob', 'message', '1')' at line 1 with query: "INSERT INTO chatmes (id, to, from, message, checked) VALUES ('1', 'freddy', 'bob', 'message', '1')" and this my php code which is supposably giving me the error <?php define('DOCROOT', __DIR__.DIRECTORY_SEPARATOR); define('APPPATH', realpath('/var/www/vhosts/grubber.co.nz/httpdocs/fuel/app/').DIRECTORY_SEPARATOR); define('PKGPATH', realpath('/var/www/vhosts/grubber.co.nz/httpdocs/fuel/packages/').DIRECTORY_SEPARATOR); define('COREPATH', realpath('/var/www/vhosts/grubber.co.nz/httpdocs/fuel/core/').DIRECTORY_SEPARATOR); require APPPATH.'bootstrap.php'; error_reporting(-1); ini_set('display_errors', 1); $to = $_GET['to']; $from = $_GET['from']; $message = $_GET['message']; $dquotes = '"'; $squotes = "'"; $message = str_replace($dquotes, "&quot", $message); $message = str_replace($squotes, "&#039", $message); DB::insert('chatmes')->set(array('id' => '1', 'to' => 'freddy', 'from' => 'bob', 'message' => 'message', 'checked' => '1'))->execute(); ?> I dont know what I am doing wrong?? Also the connection im using is PDO At the moment the only line thats giving me a error is, the db update query

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• Mysql return value as 0 in the fetch result.

  - by Karthik

  I have this two tables, -- -- Table structure for table `t1` -- CREATE TABLE `t1` ( `pid` varchar(20) collate latin1_general_ci NOT NULL, `pname` varchar(20) collate latin1_general_ci NOT NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci; -- -- Dumping data for table `t1` -- INSERT INTO `t1` VALUES ('p1', 'pro1'); INSERT INTO `t1` VALUES ('p2', 'pro2'); -- -------------------------------------------------------- -- -- Table structure for table `t2` -- CREATE TABLE `t2` ( `pid` varchar(20) collate latin1_general_ci NOT NULL, `year` int(6) NOT NULL, `price` int(3) NOT NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci; -- -- Dumping data for table `t2` -- INSERT INTO `t2` VALUES ('p1', 2009, 50); INSERT INTO `t2` VALUES ('p1', 2010, 60); INSERT INTO `t2` VALUES ('p3', 2007, 200); INSERT INTO `t2` VALUES ('p4', 2008, 501); my query is, SELECT * FROM `t1` LEFT JOIN `t2` ON t1.pid = t2.pid Getting the result, pid pname pid year price p1 pro1 p1 2009 50 p1 pro1 p1 2010 60 p2 pro2 NULL NULL NULL My question is, i want to get the price value is 0 instead of NULL. How can i write the query to getting the price value is 0. Thanks in advance for help.

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• How can I free all allocated memory at once?

  - by Tommy

  Here is what I am working with: char* qdat[][NUMTBLCOLS]; char** tdat[]; char* ptr_web_data; // Loop thru each table row of the query result set for(row_index = 0; row_index < number_rows; row_index++) { // Loop thru each column of the query result set and extract the data for(col_index = 0; col_index < number_cols; col_index++) { ptr_web_data = (char*) malloc((strlen(Data) + 1) * sizeof(char)); memcpy (ptr_web_data, column_text, strlen(column_text) + 1); qdat[row_index][web_data_index] = ptr_web_data; } } tdat[row_index] = qdat[col_index]; After the data is used, the memory allocated is released one at a time using free(). for(row_index = 0; row_index < number_rows; row_index++) { // Loop thru all columns used for(col_index = 0; col_index < SARWEBTBLCOLS; col_index++) { // Free memory block pointed to by results set array free(tdat[row_index][col_index]); } } Is there a way to release all the allocated memory at once, for this array? Thank You.

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• How to get IQueryable<> from stored procedure (entity framework)

  - by mmcteam

  I want to get IQueryable<> result when executing stored procedure. Here is peace of code that works fine: IQueryable<SomeEntitiy> someEntities; var globbalyFilteredSomeEntities = from se in m_Entities.SomeEntitiy where se.GlobalFilter == 1234 select se; I can use this to apply global filter, and later use result in such way result = globbalyFilteredSomeEntities .OrderByDescending(se => se.CreationDate) .Skip(500) .Take(10); What I want to do - use some stored procedures in global filter. I tried: Add stored procedure to m_Entities, but it returns IEnumerable<> and executes sp immediately: var globbalyFilteredSomeEntities = from se in m_Entities.SomeEntitiyStoredProcedure(1234); Materialize query using EFExtensions library, but it is IEnumerable<>. If I use AsQueryable() and OrderBy(), Skip(), Take() and after that ToList() to execute that query - I get exception that DataReader is open and I need to close it first(can't paste error - it is in russian). var globbalyFilteredSomeEntities = m_Entities.CreateStoreCommand("exec SomeEntitiyStoredProcedure(1234)") .Materialize<SomeEntitiy>(); //.AsQueryable() //.OrderByDescending(se => se.CreationDate) //.Skip(500) //.Take(10) //.ToList(); Also just skipping .AsQueryable() is not helpful - same exception.

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• Access denied when trying to access my database.

  - by Sergio Tapia

  Here's my code: <html> <head> </head> <body> <?php $user = mysql_real_escape_string($_GET["u"]); $pass = mysql_real_escape_string($_GET["p"]); $query = "SELECT * FROM usario WHERE username = '$user' AND password = '$pass'"; mysql_connect(localhost, "root", ""); @mysql_select_db("multas") or die( "Unable to select database"); $result=mysql_query($query); if(mysql_numrows($result) > 0){ echo 'si'; } ?> </body> </html> And here's the error I get when I try to run it Warning: mysql_real_escape_string() [function.mysql-real-escape-string]: Access denied for user 'ODBC'@'localhost' (using password: NO) in C:\xampp\htdocs\useraccess.php on line 7 Warning: mysql_real_escape_string() [function.mysql-real-escape-string]: A link to the server could not be established in C:\xampp\htdocs\useraccess.php on line 7 Warning: mysql_real_escape_string() [function.mysql-real-escape-string]: Access denied for user 'ODBC'@'localhost' (using password: NO) in C:\xampp\htdocs\useraccess.php on line 8 Warning: mysql_real_escape_string() [function.mysql-real-escape-string]: A link to the server could not be established in C:\xampp\htdocs\useraccess.php on line 8 Warning: mysql_numrows() expects parameter 1 to be resource, boolean given in C:\xampp\htdocs\useraccess.php on line 16

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• What information should a SVN/Versioned file commit comment contain?

  - by RenderIn

  I'm curious what kind of content should be in a versioned file commit comment. Should it describe generally what changed (e.g. "The widget screen was changed to display only active widgets") or should it be more specific (e.g. "A new condition was added to the where clause of the fetchWidget query to retrieve only active widgets by default") How atomic should a single commit be? Just the file containing the updated query in a single commit (e.g. "Updated the widget screen to display only active widgets by default"), or should that and several other changes + interface changes to a screen share the same commit with a more general description like ("Updated the widget screen: A) display only active widgets by default B) added button to toggle showing inactive widgets") I see subversion commit comments being used very differently and was wondering what others have had success with. Some comments are as brief as "updated files", while others are many paragraphs long, and others are formatted in a way that they can be queried and associated with some external system such as JIRA. I used to be extremely descriptive of the reason for the change as well as the specific technical changes. Lately I've been scaling back and just giving a general "This is what I changed on this page" kind of comment.

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• LINQ to SQL - How to efficiently do either an AND or an OR search for multiple criteria

  - by Dan Diplo

  I have an ASP.NET MVC site (which uses Linq To Sql for the ORM) and a situation where a client wants a search facility against a bespoke database whereby they can choose to either do an 'AND' search (all criteria match) or an 'OR' search (any criteria match). The query is quite complex and long and I want to know if there is a simple way I can make it do both without having to have create and maintain two different versions of the query. For instance, the current 'AND' search looks something like this (but this is a much simplified version): private IQueryable<SampleListDto> GetSampleSearchQuery(SamplesCriteria criteria) { var results = from r in Table where (r.Id == criteria.SampleId) && (r.Status.SampleStatusId == criteria.SampleStatusId) && (r.Job.JobNumber.StartsWith(criteria.JobNumber)) && (r.Description.Contains(criteria.Description)) select r; } I could copy this and replace the && with || operators to get the 'OR' version, but feel there must be a better way of achieving this. Does anybody have any suggestions how this can be achieved in an efficient and flexible way that is easy to maintain? Thanks.

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• ColdFusion 8 Slow Performance

  - by JoeBob

  We have started a new CF8 app and it is running dog slow. A test where we go around ColdFusion (queries within a database utility) show normal speed (80ms). CF8 returns the same query in something like 60 to 80 seconds! I have been looking online and seeing lots of posts about CF8 and performance problems, but don't get any overall sense of a solution; just lots of people trying things and saying that they didn't have the problem with CF7. We are also seeing instability on the server, and some errors relating to garbage collection and the memory heap. We have a number of other applications running on CF8 and they perform adequately...our programmer is not an expert or a guru, he just plugs away. We have isolated this down to a single query that takes forever to return, so it is not a complicated test. Are there any known CF8 problems or obvious tweaks that we should consider trying? If we have to start over and learn a new environment, I will never make deadline. JoeBob

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• How to get database table header information into an CSV File.

  - by Rachel

  I am trying to connect to the database and get current state of a table and update that information into csv file, with below mentioned piece of code, am able to get data information into csv file but am not able to get header information from database table into csv file. So my questions is How can I get Database Table Header information into an CSV File ? $config['database'] = 'sakila'; $config['host'] = 'localhost'; $config['username'] = 'root'; $config['password'] = ''; $d = new PDO('mysql:dbname='.$config['database'].';host='.$config['host'], $config['username'], $config['password']); $query = "SELECT * FROM actor"; $stmt = $d->prepare($query); // Execute the statement $stmt->execute(); var_dump($stmt->fetch(PDO::FETCH_ASSOC)); $data = fopen('file.csv', 'w'); while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) { echo "Hi"; // Export every row to a file fputcsv($data, $row); } Header information meaning: Vehicle Build Model car 2009 Toyota jeep 2007 Mahindra So header information for this would be Vehicle Build Model Any guidance would be highly appreciated.

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• How to handle large dataset with JPA (or at least with Hibernate)?

  - by Roman

  I need to make my web-app work with really huge datasets. At the moment I get either OutOfMemoryException or output which is being generated 1-2 minutes. Let's put it simple and suppose that we have 2 tables in DB: Worker and WorkLog with about 1000 rows in the first one and 10 000 000 rows in the second one. Latter table has several fields including 'workerId' and 'hoursWorked' fields among others. What we need is: count total hours worked by each user; list of work periods for each user. The most straightforward approach (IMO) for each task in plain SQL is: 1) select Worker.name, sum(hoursWorked) from Worker, WorkLog where Worker.id = WorkLog.workerId group by Worker.name; //results of this query should be transformed to Multimap<Worker, Long> 2) select Worker.name, WorkLog.start, WorkLog.hoursWorked from Worker, WorkLog where Worker.id = WorkLog.workerId; //results of this query should be transformed to Multimap<Worker, Period> //if it was JDBC then it would be vitally //to set resultSet.setFetchSize (someSmallNumber), ~100 So, I have two questions: how to implement each of my approaches with JPA (or at least with Hibernate); how would you handle this problem (with JPA or Hibernate of course)?

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• Facebook API - delete status

  - by Simon R

  In PHP, I'm using curl to send a delete to the fb graph api - and yet I'm getting the following error; {"error":{"type":"GraphMethodException","message":"Unsupported delete request."}} The code I'm using is; $ch = curl_init("https://graph.facebook.com/" . $status_id . ""); curl_setopt($ch, CURLOPT_VERBOSE, 1); curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); curl_setopt($ch, CURLOPT_HEADER, 0); curl_setopt($ch, CURLOPT_TIMEOUT, 120); curl_setopt($ch, CURLOPT_POST, 1); curl_setopt($ch, CURLOPT_POSTFIELDS, $query); curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "DELETE"); curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 1); curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0); curl_setopt($ch, CURLOPT_CAINFO, NULL); curl_setopt($ch, CURLOPT_CAPATH, NULL); curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 0); $result = curl_exec($ch); echo $result; $query contains the access token.

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• How do I bring forward the SELECTED option in PHP from MySQL?

  - by Derek

  Hi all, In my update form, I want the fields to recall the values that are already stored. This is very simple in a text field, but for my drop down () I'm having trouble with PHP reading the already stored name of user. Here is my query and code: $sql = "SELECT users.user_id, users.name FROM users"; $result = mysql_query($sql, $connection) or die ("Couldn't perform query $sql <br />".mysql_error()); $row = mysql_fetch_array($result);?> <label>Designated Person:</label> <select name="name" id="name"> <option value="<?php echo $row['user_id']?>" SELECTED><?php echo $row['name']?> - Current</option> <?php while($row = mysql_fetch_array($result)) { ?> <option value="<?php echo $row['user_id']; if (isset($_POST['user_id']));?>"><?php echo $row['fullname']?></option> <?php } ?> The result of this displays all of the users (as required) and lets me select a user then perform the change successfully...however the 'SELECTED' is always the first one in my database and never the user that was selected when my activity was added :( !!!

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• Is it right that Strophe.addHandler reads only first node from response?

  - by markcial

  I'm starting to learn strophe library usage and when i use addHandler to parse response it seems to read only first node of xml response so when i receive a xml like that : <body xmlns='http://jabber.org/protocol/httpbind'> <presence xmlns='jabber:client' from='test2@localhost' to='test2@localhost' type='avaliable' id='5593:sendIQ'> <status/> </presence> <presence xmlns='jabber:client' from='test@localhost' to='test2@localhost' xml:lang='en'> <status /> </presence> <iq xmlns='jabber:client' from='test2@localhost' to='test2@localhost' type='result'> <query xmlns='jabber:iq:roster'> <item subscription='both' name='test' jid='test@localhost'> <group>test group</group> </item> </query> </iq> </body> With the handler testHandler used like that : connection.addHandler(testHandler,null,"presence"); function testHandler(stanza){ console.log(stanza); } It only logs : <presence xmlns='jabber:client' from='test2@localhost' to='test2@localhost' type='avaliable' id='5593:sendIQ'> <status/> </presence> What i am missing? is it a right behaviour? Should i add more handlers to get the other stanzas? Thanks for advance

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• Mysql select - improve performance

  - by realshadow

  Hey, I am working on an e-shop which sells products only via loans. I display 10 products per page in any category, each product has 3 different price tags - 3 different loan types. Everything went pretty well during testing time, query execution time was perfect, but today when transfered the changes to the production server, the site "collapsed" in about 2 minutes. The query that is used to select loan types sometimes hangs for ~10 seconds and it happens frequently and thus it cant keep up and its hella slow. The table that is used to store the data has approximately 2 milion records and each select looks like this: SELECT * FROM products_loans WHERE KOD IN("X17/Q30-10", "X17/12", "X17/5-24") AND 369.27 BETWEEN CENA_OD AND CENA_DO; 3 loan types and the price that needs to be in range between CENA_OD and CENA_DO, thus 3 rows are returned. But since I need to display 10 products per page, I need to run it trough a modified select using OR, since I didnt find any other solution to this. I have asked about it here, but got no answer. As mentioned in the referencing post, this has to be done separately since there is no column that could be used in a join (except of course price and code, but that ended very, very badly). Here is the show create table, kod and CENA_OD/CENA_DO very indexed via INDEX. CREATE TABLE `products_loans` ( `KOEF_ID` bigint(20) NOT NULL, `KOD` varchar(30) NOT NULL, `AKONTACIA` int(11) NOT NULL, `POCET_SPLATOK` int(11) NOT NULL, `koeficient` decimal(10,2) NOT NULL default '0.00', `CENA_OD` decimal(10,2) default NULL, `CENA_DO` decimal(10,2) default NULL, `PREDAJNA_CENA` decimal(10,2) default NULL, `AKONTACIA_SUMA` decimal(10,2) default NULL, `TYP_VYHODY` varchar(4) default NULL, `stage` smallint(6) NOT NULL default '1', PRIMARY KEY (`KOEF_ID`), KEY `CENA_OD` (`CENA_OD`), KEY `CENA_DO` (`CENA_DO`), KEY `KOD` (`KOD`), KEY `stage` (`stage`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 And also selecting all loan types and later filtering them trough php doesnt work good, since each type has over 50k records and the select takes too much time as well... Any ides about improving the speed are appreciated.

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• Where should I put contextual data related to an Object that is not really a property of the object?

  - by RenderIn

  I have a Car class. It has three properties: id, color and model. In a particular query I want to return all the cars and their properties, and I also want to return a true/false field called "searcherKnowsOwner" which is a field I calculate in my database query based on whether or not the individual conducting the search knows the owner. I have a database function that takes the ID of the searcher and the ID of the car and returns a boolean. My car class looks like this (pseudocode): class Car{ int id; Color color; Model model; } I have a screen where I want to display all the cars, but I also want to display a flag next to each car if the person viewing the page knows the owner of that car. Should I add a field to the Car class, a boolean searcherKnowsOwner? It's not a property of the car, but is actually a property of the user conducting the search. But this seems like the most efficient place to put this information.

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• Ordering by a max or a min from another table

  - by Paul Tomblin

  I have a table that consists of a unique id, and a few other attributes. It holds "schedules". Then I have another table that holds a list of all the times each schedule has or will "fire". This isn't the exact schema, but it's close: create table schedule ( id varchar(40) primary key, attr1 int, attr2 varchar(20) ); create table schedule_times ( id varchar(40) foreign key schedule(id), fire_date date ); I want to query the schedule table, getting the attributes and the next and previous fire_dates, in Java, sometimes ordering on one of the attributes, but sometimes ordering on either previous fire_date or the next fire_date. Ordering by the attributes is easy, I just stick an "order by" into the string while I'm building my prepared statement. I'm not even sure how to go about selecting the last fire_date and the next one in a single query - I know that I can find the next fire_date for a given id by doing a SELECT min(fire_date) FROM schedule_times WHERE id = ? AND fire_date > sysdate; and the similar thing for previous fire_date using max() and fire_date < sysdate. I'm just drawing a blank on how to incorporate that into a single select from the schedule so I can get both next and previous fire_date in one shot, and also how to order by either of those attributes.

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• How to export Oracle statistics

  - by A_M

  Hi, I am writing some new SQL queries and want to check the query plans that the Oracle query optimiser would come up with in production. My development database doesn't have anything like the data volumes of the production database. How can I export database statistics from a production database and re-import them into a development database? I don't have access to the production database, so I can't simply generate explain plans on production without going through a third party hosting organisation. This is painful. So I want a local database which is in some way representative of production on which I can try out different things. Also, this is for a legacy application. I'd like to "improve" the schema, by adding appropriate indexes. constraints, etc. I need to do this in my development database first, before rolling out to test and production. If I add an index and re-generate statistics in development, then the statistics will be generated around the development data volumes, which makes it difficult to assess the impact my changes on production. Does anyone have any tips on how to deal with this? Or is it just a case of fixing unexpected behaviour once we've discovered it on production? I do have a staging database with production volumes, but again I have to go through a third party to run queries against this, which is painful. So I'm looking for ways to cut out the middle man as much as possible. All this is using Oracle 9i. Thanks.

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• How to transform vertical table into horizontal table?

  - by avivo

  Hello, I have one table Person: Id Name 1 Person1 2 Person2 3 Person3 And I have its child table Profile: Id PersonId FieldName Value 1 1 Firstname Alex 2 1 Lastname Balmer 3 1 Email [email protected] 4 1 Phone +1 2 30004000 And I want to get data from these two tables in one row like this: Id Name Firstname Lastname Email Phone 1 Person1 Alex Balmer [email protected] +1 2 30004000 What is the most optimized query to get these vertical (key, value) values in one row like this? Now I have a problem that I done four joins of child table to parent table because I need to get these four fields. Some optimization is for sure possible. I would like to be able to modify this query in easy way when I add new field (key,value). What is the best way to do this? To create some StoreProcedure? I would like to have strongly types in my DB layer (C#) and using LINQ (when programming) so it means when I add some new Key, Value pair in Profile table I would like to do minimal modifications in DB and C# if possible. Actually I am trying to get some best practices in this case.

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• What is happening in this T-SQL code? (Concatenting the results of a SELECT statement)

  - by Ben McCormack

  I'm just starting to learn T-SQL and could use some help in understanding what's going on in a particular block of code. I modified some code in an answer I received in a previous question, and here is the code in question: DECLARE @column_list AS varchar(max) SELECT @column_list = COALESCE(@column_list, ',') + 'SUM(Case When Sku2=' + CONVERT(varchar, Sku2) + ' Then Quantity Else 0 End) As [' + CONVERT(varchar, Sku2) + ' - ' + Convert(varchar,Description) +'],' FROM OrderDetailDeliveryReview Inner Join InvMast on SKU2 = SKU and LocationTypeID=4 GROUP BY Sku2 , Description ORDER BY Sku2 Set @column_list = Left(@column_list,Len(@column_list)-1) Select @column_list ---------------------------------------- 1 row is returned: ,SUM(Case When Sku2=157 Then Quantity Else 0 End) As [157 -..., SUM(Case ... The T-SQL code does exactly what I want, which is to make a single result based on the results of a query, which will then be used in another query. However, I can't figure out how the SELECT @column_list =... statement is putting multiple values into a single string of characters by being inside a SELECT statement. Without the assignment to @column_list, the SELECT statement would simply return multiple rows. How is it that by having the variable within the SELECT statement that the results get "flattened" down into one value? How should I read this T-SQL to properly understand what's going on?

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• [MySQL/PHP] Avoid using RAND()

  - by Andrew Ellis

  So... I have never had a need to do a random SELECT on a MySQL DB until this project I'm working on. After researching it seems the general populous says that using RAND() is a bad idea. I found an article that explains how to do another type of random select. Basically, if I want to select 5 random elements, I should do the following (I'm using the Kohana framework here)? If not, what is a better solution? Thanks, Andrew <?php final class Offers extends Model { /** * Loads a random set of offers. * * @param integer $limit * @return array */ public function random_offers($limit = 5) { // Find the highest offer_id $sql = ' SELECT MAX(offer_id) AS max_offer_id FROM offers '; $max_offer_id = DB::query(Database::SELECT, $sql) ->execute($this->_db) ->get('max_offer_id'); // Check to make sure we're not trying to load more offers // than there really is... if ($max_offer_id < $limit) { $limit = $max_offer_id; } $used = array(); $ids = ''; for ($i = 0; $i < $limit; ) { $rand = mt_rand(1, $max_offer_id); if (!isset($used[$rand])) { // Flag the ID as used $used[$rand] = TRUE; // Set the ID if ($i > 0) $ids .= ','; $ids .= $rand; ++$i; } } $sql = ' SELECT offer_id, offer_name FROM offers WHERE offer_id IN(:ids) '; $offers = DB::query(Database::SELECT, $sql) ->param(':ids', $ids) ->as_object(); ->execute($this->_db); return $offers; } }

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• Hibernate noob fetch join problem

  - by Bruce

  Hi all I have two classes, Test2 and Test3. Test2 has an attribute test3 that is an instance of Test3. In other words, I have a unidirectional OneToOne association, with test2 having a reference to test3. When I select Test2 from the db, I can see that a separate select is being made to get the details of the associated test3 class. This is the famous 1+N selects problem. To fix this to use a single select, I am trying to use the fetch=join annotation, which I understand to be @Fetch(FetchMode.JOIN) However, with fetch set to join, I still see separate selects. Here are the relevant portions of my setup.. hibernate.cfg.xml: <property name="max_fetch_depth">2</property> Test2: public class Test2 { @OneToOne (cascade=CascadeType.ALL , fetch=FetchType.EAGER) @JoinColumn (name="test3_id") @Fetch(FetchMode.JOIN) public Test3 getTest3() { return test3; } NB I set the FetchType to EAGER out of desperation, even though it defaults to EAGER anyway for OneToOne mappings, but it made no difference. Thanks for any help! Edit: I've pretty much given up on trying to use FetchMode.JOIN - can anyone confirm that they have got it to work ie produce a left outer join? In the docs I see that "Usually, the mapping document is not used to customize fetching. Instead, we keep the default behavior, and override it for a particular transaction, using left join fetch in HQL" If I do a left join fetch instead: query = session.createQuery("from Test2 t2 left join fetch t2.test3"); then I do indeed get the results I want - ie a left outer join in the query.

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