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• User has many computers, computers have many attributes in different tables, best way to JOIN?

  - by krismeld

  I have a table for users: USERS: ID | NAME | ---------------- 1 | JOHN | 2 | STEVE | a table for computers: COMPUTERS: ID | USER_ID | ------------------ 13 | 1 | 14 | 1 | a table for processors: PROCESSORS: ID | NAME | --------------------------- 27 | PROCESSOR TYPE 1 | 28 | PROCESSOR TYPE 2 | and a table for harddrives: HARDDRIVES: ID | NAME | ---------------------------| 35 | HARDDRIVE TYPE 25 | 36 | HARDDRIVE TYPE 90 | Each computer can have many attributes from the different attributes tables (processors, harddrives etc), so I have intersection tables like this, to link the attributes to the computers: COMPUTER_PROCESSORS: C_ID | P_ID | --------------| 13 | 27 | 13 | 28 | 14 | 27 | COMPUTER_HARDDRIVES: C_ID | H_ID | --------------| 13 | 35 | So user JOHN, with id 1 owns computer 13 and 14. Computer 13 has processor 27 and 28, and computer 13 has harddrive 35. Computer 14 has processor 27 and no harddrive. Given a user's id, I would like to retrieve a list of that user's computers with each computers attributes. I have figured out a query that gives me a somewhat of a result: SELECT computers.id, processors.id AS p_id, processors.name AS p_name, harddrives.id AS h_id, harddrives.name AS h_name, FROM computers JOIN computer_processors ON (computer_processors.c_id = computers.id) JOIN processors ON (processors.id = computer_processors.p_id) JOIN computer_harddrives ON (computer_harddrives.c_id = computers.id) JOIN harddrives ON (harddrives.id = computer_harddrives.h_id) WHERE computers.user_id = 1 Result: ID | P_ID | P_NAME | H_ID | H_NAME | ----------------------------------------------------------- 13 | 27 | PROCESSOR TYPE 1 | 35 | HARDDRIVE TYPE 25 | 13 | 28 | PROCESSOR TYPE 2 | 35 | HARDDRIVE TYPE 25 | But this has several problems... Computer 14 doesnt show up, because it has no harddrive. Can I somehow make an OUTER JOIN to make sure that all computers show up, even if there a some attributes they don't have? Computer 13 shows up twice, with the same harddrive listet for both. When more attributes are added to a computer (like 3 blocks of ram), the number of rows returned for that computer gets pretty big, and it makes it had to sort the result out in application code. Can I somehow make a query, that groups the two returned rows together? Or a query that returns NULL in the h_name column in the second row, so that all values returned are unique? EDIT: What I would like to return is something like this: ID | P_ID | P_NAME | H_ID | H_NAME | ----------------------------------------------------------- 13 | 27 | PROCESSOR TYPE 1 | 35 | HARDDRIVE TYPE 25 | 13 | 28 | PROCESSOR TYPE 2 | 35 | NULL | 14 | 27 | PROCESSOR TYPE 1 | NULL | NULL | Or whatever result that make it easy to turn it into an array like this [13] => [P_NAME] => [0] => PROCESSOR TYPE 1 [1] => PROCESSOR TYPE 2 [H_NAME] => [0] => HARDDRIVE TYPE 25 [14] => [P_NAME] => [0] => PROCESSOR TYPE 1

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• Installing databases after installation of server.

  - by claws

  Hello, I my software I need the client to install a database server (MySQL in my case). I'm deploying the setup and making user install it like a pre-requisite. After installing the DBMS server. I need to setup databases (that I created) on the client machine. How to do this automatically (as part of installation.)?

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• Why am I unable to create a trigger using my SqlCommand?

  - by acidzombie24

  The line cmd.ExecuteNonQuery(); cmd.CommandText CREATE TRIGGER subscription_trig_0 ON subscription AFTER INSERT AS UPDATE user_data SET msg_count=msg_count+1 FROM user_data JOIN INSERTED ON user_data.id = INSERTED.recipient; The exception: Incorrect syntax near the keyword 'TRIGGER'. Then using VS 2010, connected to the very same file (a mdf file) I run the query above and I get a success message. WTF!

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• A case-insensitive related implementation problem

  - by Robert

  Hi All, I am going through a final refinement posted by the client, which needs me to do a case-insesitive query. I will basically walk through how this simple program works. First of all, in my Java class, I did a fairly simple webpage parsing: title=(String)results.get("title"); doc = docBuilder.parse("http://" + server + ":" + port + "/exist/rest/db/wb/xql/media_lookup.xql?" + "&title=" + title); This Java statement references an XQuery file "media_lookup.xql" which is stored on localhost, and the only parameter we are passing is the string "title". Secondly, let's take at look at that XQuery file: $title := request:get-parameter('title',""), $mediaNodes := doc('/db/wb/portfolio/media_data.xml'), $query := $mediaNodes//media[contains(title,$title)], Then it will evaluate that query. This XQuery will get the "title" parameter that are passes from our Java class, and query the "media_data" xml file stored in the database, which contains a bunch of media nodes with a 'title' element node. As you may expect, this simple query will just match those media nodes whose 'title' element contains a substring of what the value of string 'title' is. So if our 'title' is "Chi", it will return media nodes whose title may be "Chicago" or "Chicken". The refinment request posted by the client is that there should be NO case-sensitivity. The very intuitive way is to modify the XQuery statement by using a lower-case funtion in it, like: $query := $mediaNodes//media[contains(lower-case(title/text(),lower-case($title))], However, the question comes: this modified query will run my machine into memory overflow. Since my "media_data.xml" is quite huge and contains thouands of millions of media nodes, I assume the lower-case() function will run on each of the entries, thus causing the machine to crash. I've talked with some experienced XQuery programmer, and they think I should use an index to solve this problem, and I will definitely research into that. But before that, I am just posting this problem here to get other ideas or any suggestions, do you think any other way may help? for example, could I tweak the Java parse statement to realize the case-insensitivity? Since I think I saw some people did some string concatination by using "contains." in Java before passing it to the server. Any idea or help is welcomed, thanks in advance.

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• How to increase query speed without using full-text search?

  - by andre matos

  This is my simple query; By searching selectnothing I'm sure I'll have no hits. SELECT nome_t FROM myTable WHERE nome_t ILIKE '%selectnothing%'; This is the EXPLAIN ANALYZE VERBOSE Seq Scan on myTable (cost=0.00..15259.04 rows=37 width=29) (actual time=2153.061..2153.061 rows=0 loops=1) Output: nome_t Filter: (nome_t ~~* '%selectnothing%'::text) Total runtime: 2153.116 ms myTable has around 350k rows and the table definition is something like: CREATE TABLE myTable ( nome_t text NOT NULL, ) I have an index on nome_t as stated below: CREATE INDEX idx_m_nome_t ON myTable USING btree (nome_t); Although this is clearly a good candidate for Fulltext search I would like to rule that option out for now. This query is meant to be run from a web application and currently it's taking around 2 seconds which is obviously too much; Is there anything I can do, like using other index methods, to improve the speed of this query?

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• .NET/C# Drizzle database client

  - by FlappySocks

  I am planning to use Drizzle in my next C# Mono app. Since there is no C# client available for Drizzle, I thought I would have a stab at writing my own by converting the Java client, and then making it work with DBLinq. Having seen the Java client, I realise that it's a longer job that I had anticipated, and I don't have the time. Besides the Java client is not all that mature yet. Since there is an official Drizzle C client library (libdrizzle), writing a C# wrapper might be the best solution. Are there any tools available that can assist in generating the code for this?

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• Creating a login form and validating inputs in C# using linq to sql

  - by Allan

  I am quite new to C# and .NET programming. I am working on an application and want to create a login form for which if the User enters their credentials it checks to see if user details exist in Database and then allows the user access to the application.

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• Is there an alternative to Microsoft.SqlServer.Management.Smo.SqlDataType that includes a value for

  - by Daniel Schaffer

  The Microsoft.SqlServer.Management.Smo.SqlDataType enum has a value for the timestamp type but not rowversion. I'm looking for an updated version of the assembly or an alternate enum type that supports it. The existing enum has a value for Timestamp, but according to the rowversion documentation, timestamp is "deprecated and will be removed in a future version". I prefer to avoid using deprecated things :)

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• unique id in more than one table [MySQL]

  - by monthon1

  I want to make auto increment id in two MySQL tables (if in first table there is id=4 then it cannot be id=4 in the second table). My question is how can I do that in the best way?

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• How Optimize sql query make it faster

  - by user502083

  Hello every one : I have a very simple small database, 2 of tables are: Node (Node_ID, Node_name, Node_Date) : Node_ID is primary key Citation (Origin_Id, Target_Id) : PRIMARY KEY (Origin_Id, Target_Id) each is FK in Node Now I write a query that first find all citations that their Origin_Id has a specific date and then I want to know what are the target dates of these records. I'm using sqlite in python the Node table has 3000 record and Citation has 9000 records, and my query is like this in a function: def cited_years_list(self, date): c=self.cur try: c.execute("""select n.Node_Date,count(*) from Node n INNER JOIN (select c.Origin_Id AS Origin_Id, c.Target_Id AS Target_Id, n.Node_Date AS Date from CITATION c INNER JOIN NODE n ON c.Origin_Id=n.Node_Id where CAST(n.Node_Date as INT)={0}) VW ON VW.Target_Id=n.Node_Id GROUP BY n.Node_Date;""".format(date)) cited_years=c.fetchall() self.conn.commit() print('Cited Years are : \n ',str(cited_years)) except Exception as e: print('Cited Years retrival failed ',e) return cited_years Then I call this function for some specific years, But it's crazy slowwwwwwwww :( (around 1 min for a specific year) Although my query works fine, it is slow. would you please give me a suggestion to make it faster? I'd appreciate any idea about optimizing this query :) I also should mention that I have indices on Origin_Id and Target_Id, so the inner join should be pretty fast, but it's not!!!

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• Problem with checkboxes, sql select statements & php

  - by smokey20

  I am trying to display some rows from a database table based on choices submitted by the user. Here is my form code <form action="choice.php" method="POST" > <input type="checkbox" name="variable[]" value="Apple">Apple <input type="checkbox" name="variable[]" value="Banana">Banana <input type="checkbox" name="variable[]" value="Orange">Orange <input type="checkbox" name="variable[]" value="Melon">Melon <input type="checkbox" name="variable[]" value="Blackberry">Blackberry From what I understand I am placing the values of these into an array called variable. Two of my columns are called receipe name and ingredients(each field under ingredients can store a number of fruits). What I would like to do is, if a number of checkboxes are selected then the receipe name/s is displayed. Here is my php code. <?php // Make a MySQL Connection mysql_connect("localhost", "*****", "*****") or die(mysql_error()); mysql_select_db("****") or die(mysql_error()); $variable=$_POST['variable']; foreach ($variable as $variablename) { echo "$variablename is checked"; } $query = "SELECT receipename FROM fruit WHERE $variable like ingredients"; $row = mysql_fetch_assoc($result); foreach ($_POST['variabble'] as $ingredients) echo $row[$ingredients] . '<br/>'; ?> I am very new to php and just wish to display the data, I do not need to perform any actions on it. I have tried many select statements but I cannot get any results to display. My db connection is fine and it does print out what variables are checked. Many thanks in advance.

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• Run SSIS Package from T-SQL

  - by Dr. Zim

  I noticed you can use the following stored procedures (in order) to schedule a SSIS package: msdb.dbo.sp_add_category @class=N'JOB', @type=N'LOCAL', @name=N'[Uncategorized (Local)]' msdb.dbo.sp_add_job ... msdb.dbo.sp_add_jobstep ... msdb.dbo.sp_update_job ... msdb.dbo.sp_add_jobschedule ... msdb.dbo.sp_add_jobserver ... (You can see an example by right clicking a scheduled job and selecting "Script Job as- Create To".) AND you can use sp_start_job to execute the job immediately, effectively running SSIS packages on demand. Question: does anyone know of any msdb.dbo.[...] stored procedures that simply allow you to run SSIS packages on the fly without using sp_cmdshell directly, or some easier approach?

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• Any way to optimize this MySQL query?

  - by manyxcxi

  My table looks like this: `MyDB`.`Details` ( `id` bigint(20) NOT NULL, `run_id` int(11) NOT NULL, `element_name` varchar(255) NOT NULL, `value` text, `line_order` int(11) default NULL, `column_order` int(11) default NULL ); I have the following SELECT statement in a stored procedure SELECT RULE ,TITLE ,SUM(IF(t.PASSED='Y',1,0)) AS PASS ,SUM(IF(t.PASSED='N',1,0)) AS FAIL FROM ( SELECT a.line_order ,MAX(CASE WHEN a.element_name = 'PASSED' THEN a.`value` END) AS PASSED ,MAX(CASE WHEN a.element_name = 'RULE' THEN a.`value` END) AS RULE ,MAX(CASE WHEN a.element_name = 'TITLE' THEN a.`value` END) AS TITLE FROM Details a WHERE run_id = runId GROUP BY line_order ) t GROUP BY RULE, TITLE; *runId is an input parameter to the stored procedure. This query takes about 14 seconds to run. The table has 214856 rows, and the particular run_id I am filtering on has 162204 records. It's not on a super high power machine, but I feel like I could be doing this more efficiently. My main goal is to summarize by Rule and Title and show Pass and Fail count columns.

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• How to make activerecord use a field generated on the fly by find_by_sql

  - by Tam

  I'm using find_by_sql with Activerecord which I generate another field there that doesn't in the original table as a combination of different fields like: select (field1 + field2) as new_field_name If I try to access the newly generated field like: @user.new_field_name I get nothing! How do you suggest I should approach this problem

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• How to query database where date and time field are separate?

  - by learner

  In Table, Time and date fields are two separate fields. I need to make a query something like this give all records where date and time <= givenDateTime. How do i do that please?

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• Foreign Keys and Primary Keys at the same time

  - by Bader

  hello , i am trying to create table (orderdetails) , the table has two FKs and PKs at the same keys here is my code create table OrderDetails2 ( PFOrder_ID Number(3) PFProduct_ID Number(3) CONSTRAINT PF PRIMARY KEY (PFOrder_ID,PFProduct_ID), CONSTRAINT FK_1 FOREIGN KEY (PFProudct_ID) REFERENCES Product(Product_ID), CONSTRAINT FK_2 FOREIGN KEY (PFOrder_ID) REFERENCES Orderr(Order_ID) ); i am using Oracle express , a problem pops when i run the code , here is it ORA-00907: missing right parenthesis what is the problem ?

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• DB Cursor fetching in Web Applications

  - by Alix Axel

  I never understood this: in web development whe[n|re] does it make sense to fetch results one by one? I mean, why should I use PDOStatement->fetch*() when I can use PDOStatement->fetchAll()?

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• why datetime.now not work when I didn't use tolist?

  - by MemoryLeak

  When I use datacontext.News .Where(p => p.status == true) .Where(p => p.date <= DateTime.Now) .ToList(); the system will return no results; When I use datacontext.News .Where(p => p.status == true) .ToList() .Where(p => p.date <= DateTime.Now) .ToList(); system will return expected results. Can anyone tell me what's up? Thanks in advance !

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• HQl equivalent of sql query

  - by kash

  String SQL_QUERY = "SELECT count(*) FROM (SELECT * FROM Url as U where U.pageType=" + 1 + " group by U.pageId having count(U.pageId) = 1)"; query = session.createQuery(SQL_QUERY); I am getting an error org.hibernate.hql.ast.QuerySyntaxException: unexpected token: ( near line 1, column 23 [ SELECT count() FROM (SELECT * FROM Url as U where U.pageType = 2 group by U.pageId having count(U.pageId) = 1)]

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• MD5 hash validation failing for unknown reason in PHP

  - by Sennheiser

  I'm writing a login form, and it converts the given password to an MD5 hash with md5($password), then matches it to an already-hashed record in my database. I know for sure that the database record is correct in this case. However, it doesn't log me in and claims the password is incorrect. Here's my code: $password = mysql_real_escape_string($_POST["password"]); ...more code... $passwordQuery = mysql_fetch_row(mysql_query(("SELECT password FROM users WHERE email = '$userEmail'"))); ...some code... elseif(md5($password) != $passwordQuery) { $_SESSION["noPass"] = "That password is incorrect."; } ...more code after... I tried pulling just the value of md5($password) and that matched up when I visually compared it. However, I can't get the comparison to work in PHP. Perhaps it is because the MySQL record is stored as text, and the MD5 is something else?

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• select from multiple tables but ordering by a datetime field

  - by Chris Mccabe

  I have 3 tables that are unrelated (related that each contains data for a different social network). Each has a datetime field dated- I'm already grouping by hour as you can see below (this one below for linked_in) SELECT count(*), date_format(dated, '%Y:%m:%d %H') as hour FROM upd8r_linked_in_accts WHERE CAST(dated AS DATE) = '".$start_date."' GROUP BY hour I would like to know how to do a total across all 3 networks- the tables for the three are CREATE TABLE IF NOT EXISTS `upd8r_facebook_accts` ( `id` int(11) NOT NULL AUTO_INCREMENT, `owner_id` varchar(50) NOT NULL, `user_id` int(11) NOT NULL, `fb_id` bigint(30) NOT NULL, `dated` datetime NOT NULL, PRIMARY KEY (`id`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=80 ; CREATE TABLE IF NOT EXISTS `upd8r_linked_in_accts` ( `id` int(11) NOT NULL AUTO_INCREMENT, `owner_id` varchar(50) NOT NULL, `user_id` int(11) NOT NULL, `linked_in` varchar(200) NOT NULL, `oauth_secret` varchar(100) NOT NULL, `first_count` int(11) NOT NULL, `second_count` int(11) NOT NULL, `dated` datetime NOT NULL, PRIMARY KEY (`id`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=200 ; CREATE TABLE IF NOT EXISTS `upd8r_twitter_accts` ( `id` int(11) NOT NULL AUTO_INCREMENT, `owner_id` varchar(50) NOT NULL, `user_id` int(11) NOT NULL, `twitter` varchar(200) NOT NULL, `twitter_secret` varchar(100) NOT NULL, `dated` datetime NOT NULL, PRIMARY KEY (`id`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=9 ; something like this ? (SELECT count(*), date_format(dated, '%Y:%m:%d %H') as hour FROM upd8r_linked_in_accts WHERE CAST(dated AS DATE) = '".$start_date."') UNION ALL (SELECT count(*), date_format(dated, '%Y:%m:%d %H') as hour FROM upd8r_facebook_accts WHERE CAST(dated AS DATE) = '".$start_date."') UNION ALL (SELECT count(*), date_format(dated, '%Y:%m:%d %H') as hour FROM upd8r_twitter_accts WHERE CAST(dated AS DATE) = '".$start_date."') UNION ALL GROUP BY hour

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• How to select the last 2-element group by a topic_id in MySQL

  - by Luca Romagnoli

  Hi i have to select the 2 lastest element for every topic ex: table: msg id | topic_id ----------- 1 | 1 2 | 1 3 | 1 4 | 1 5 | 2 6 | 2 7 | 2 8 | 3 9 | 3 10 | 3 i want obtain these rows: 3 1 4 1 6 2 7 2 9 3 10 3 How can i do? thanks

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• Why does Linq to Entities generate Left Outer Joins?

  - by DJCasey

  I was wondering if anyone knew why linq to entities always seems to generate left outer joins. I would understand it on an optional relationship but it doesn't make good sense when the relationship is mandatory. Does anyone have any idea how to make it generate inner joins instead?

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• Incorrect syntax inserting data into table

  - by SelectDistinct

  I am having some trouble with my update() method. The idea is that the user Provides a recipe name, ingredients, instructions and then selects an image using Filestream. Once the user clicks 'Add Recipe' this will call the update method, however as things stand I am getting an error which is mentioning the contents of the text box: Here is the update() method code: private void updatedata() { // filesteam object to read the image // full length of image to a byte array try { // try to see if the image has a valid path if (imagename != "") { FileStream fs; fs = new FileStream(@imagename, FileMode.Open, FileAccess.Read); // a byte array to read the image byte[] picbyte = new byte[fs.Length]; fs.Read(picbyte, 0, System.Convert.ToInt32(fs.Length)); fs.Close(); //open the database using odp.net and insert the lines string connstr = @"Server=mypcname\SQLEXPRESS;Database=RecipeOrganiser;Trusted_Connection=True"; SqlConnection conn = new SqlConnection(connstr); conn.Open(); string query; query = "insert into Recipes(RecipeName,RecipeImage,RecipeIngredients,RecipeInstructions) values (" + textBox1.Text + "," + " @pic" + "," + textBox2.Text + "," + textBox3.Text + ")"; SqlParameter picparameter = new SqlParameter(); picparameter.SqlDbType = SqlDbType.Image; picparameter.ParameterName = "pic"; picparameter.Value = picbyte; SqlCommand cmd = new SqlCommand(query, conn); cmd.Parameters.Add(picparameter); cmd.ExecuteNonQuery(); MessageBox.Show("Image successfully saved"); cmd.Dispose(); conn.Close(); conn.Dispose(); Connection(); } } catch (Exception ex) { MessageBox.Show(ex.Message); } } Can anyone see where I have gone wrong with the insert into Recipes query or suggest an alternative approach to this part of the code?

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• How to map combinations of things to a relational database?

  - by Space_C0wb0y

  I have a table whose records represent certain objects. For the sake of simplicity I am going to assume that the table only has one row, and that is the unique ObjectId. Now I need a way to store combinations of objects from that table. The combinations have to be unique, but can be of arbitrary length. For example, if I have the ObjectIds 1,2,3,4 I want to store the following combinations: {1,2}, {1,3,4}, {2,4}, {1,2,3,4} The ordering is not necessary. My current implementation is to have a table Combinations that maps ObjectIds to CombinationIds. So every combination receives a unique Id: ObjectId | CombinationId ------------------------ 1 | 1 2 | 1 1 | 2 3 | 2 4 | 2 This is the mapping for the first two combinations of the example above. The problem is, that the query for finding the CombinationId of a specific Combination seems to be very complex. The two main usage scenarios for this table will be to iterate over all combinations, and the retrieve a specific combination. The table will be created once and never be updated. I am using SQLite through JDBC. Is there any simpler way or a best practice to implement such a mapping?

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