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  • Is it possible to write a SQL query to return specific rows, but then join some columns of those row

    - by Rob
    I'm having trouble wrapping my head around how to write this query. A hypothetical problem that is that same as the one I'm trying to solve: Say I have a table of apples. Each apple has numerous attributes, such as color_id, variety_id and the orchard_id they were picked from. The color_id, variety_id, and orchard_id all refer to their respective tables: colors, varieties, and orchards. Now, say I need to query for all apples that have color_id = '3', which refers to yellow in the colors table. I want to somehow obtain this yellow value from the query. Make sense? Here's what I was trying: SELECT * FROM apples, colors.id WHERE color_id = '3' LEFT JOIN colors ON apples.color_id = colors.id

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  • GQL Query with __key__ in List of KEYs

    - by bossylobster
    In the GQL reference [1], it is encouraged to use the IN keyword with a list of values, and to construct a Key from hand the GQL query SELECT * FROM MyModel WHERE __key__ = KEY('MyModel', 'my_model_key') will succeed. However, using the code you would expect to work: SELECT * FROM MyModel WHERE __key__ IN (KEY('MyModel', 'my_model_key1'), KEY('MyModel', 'my_model_key2')) in the Datastore Viewer, there is a complaint of "Invalid GQL query string." What is the correct way to format such a query? [1] http://code.google.com/appengine/docs/python/datastore/gqlreference.html PS I know there are more efficient ways to do this in Python (without constructing a GQL query) and using the remote_api, but each call to the remote_api counts against quota. In an environment where quota is not (necessarily) free, quick and dirty queries are very helpful.

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  • Regex Question to Grab Keys

    - by Braveyard
    Hello, I have this kinda template text : Hello {#Name#}, Thanks for coming blah on {#Date#} and we love to see you again here with {#President#} So I am trying to get {#...#} templates parts and put them into an array. But my expression didn't work : \b(?<=\{\#)(.*)(?=\#\})\b The result became something like this for this sample text : {#Something#} Hello {#Brand#} Result : Something#} Hello {#Brand

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  • JPA 2.0 Eclipse Link ... Composite primary keys

    - by Parhs
    I have two entities(actually more but it doenst matter) Exam and Exam_Normals Its a oneToMany relationship... The problem is that i need a primary key for Exams_Normals PK (Exam_ID Item) Item should be 1 2 3 4 5 etc.... But cant achieve it getting errors An alternative would be to: I cound use an IDENTITY and a ManyToOne relationship at Exam_Normals but that should be like PK(Exam_Normals_ID) and a reference to Exam and an extra collumn Item to keep an order.. SO 3 collumns But to avoid the alternative tried I tried with @IdClass and got errors Tried @EmbeddedID everything nothing works Any idea??

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  • SQL: Is it quicker to insert sorted data into a table?

    - by AngryWhenHungry
    A table in Sybase has a unique varchar(32) column, and a few other columns. It is indexed on this column too. At regular intervals, I need to truncate it, and repopulate it with fresh data from other tables. insert into MyTable select list_of_columns from OtherTable where some_simple_conditions order by MyUniqueId If we are dealing with a few thousand rows, would it help speed up the insert if we have the order by clause for the select? If so, would this gain in time compensate for the extra time needed to order the select query? I could try this out, but currently my data set is small and the results don't say much.

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  • Basic question about encryption - what exactly are keys?

    - by Tomas
    Hi, I was browsing and found good articles about encryption. However, none of them described why the key lenght is important and what exactly the key is used for. My guess is that could work this way: 0101001101010101010 Key: 01010010101010010101 //the longer the key, the longer unique sequence XOR or smth: //result Is this at least a bit how it works or I am missing something? Thanks

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  • What's SQL table name for table between 'Users' and 'UserTypes' ?

    - by Space Cracker
    i have tow tables in my database : Users : contain user information UserTypes : contain the names of user types ( student , teacher , specialist ) - I can't rename it to 'Types' as we have a table with this name relation between Users and UserTypes many to many .. so i'll create a table that have UserID(FK) with UserTypeID(FK) but I try to find best name for that table ... any suggestion please ?

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  • Oracle SQL: Multiple Subqueries Unioned Without Running Original Query Multiple Times.

    - by Bob
    So I've got a very large database, and need to work on a subset ~1% of the data to dump into an excel spreadsheet to make a graph. Ideally, I could select out the subset of data and then run multiple select queries on that, which are then UNION'ed together. Is this even possible? I can't seem to find anyone else trying to do this and would improve the performance of my current query quite a bit. Right now I have something like this: SELECT ( SELECT ( SELECT( long list of requirements ) UNION SELECT( slightly different long list of requirements ) ) ) and it would be nice if i could group the commonalities of the two long requirements and have simple differences between the two select statements being unioned.

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  • Why did the following linq to sql query generate a subquery?

    - by Xaisoft
    I did the following query: var list = from book in books where book.price > 50 select book; list = list.Take(50); I would expect the above to generate something like: SELECT top 50 id, title, price, author FROM Books WHERE price > 50 but it generates: SELECT [Limit1].[C1] as [C1] [Limit1].[id] as [Id], [Limit1].[title] as [title], [Limit1].[price] as [price], [Limit1].[author] FROM (SELECT TOP (50) [Extent1].[id] as as [Id], [Extent1].[title] as [title], [Extent1].[price] as [price], [Extent1].[author] as [author] FROM Books as [Extent1] WHERE [Extent1].[price] > 50 ) AS [Limit1] Why does the above linq query generate a subquery and where does the C1 come from?

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  • SQL: Using a CASE Statement to update a 1000 rows at once, how??

    - by SoLoGHoST
    Ok, I would like to use a CASE STATEMENT for this, but I am lost with this. Basically, I need to update a ton of rows, but just on the "position" column. I need to update all "position" values from 0 - count(position) for each id_layout_position column per id_layout column. Here's what I got for a regular update, but I don't wanna throw this into a foreach loop, as it would take forever to do it. I'm using SMF (Simple Machines Forums), so it might look a little different, but the idea is the same, and CASE statements are supported... $smcFunc['db_query']('', ' UPDATE {db_prefix}dp_positions SET position = {int:position} WHERE id_layout_position = {int:id_layout_position} AND id_layout = {int:id_layout}', array( 'position' => $position++, 'id_layout_position' => (int) $id_layout_position, 'id_layout' => (int) $id_layout, ) ); Anyways, I need to apply some sort of CASE on this so that I can auto-increment by 1 all values that it finds and update to the next possible value. I know I'm doing this wrong, even in this QUERY. But I'm totally lost when it comes to CASES. Here's an example of a CASE being used within SMF, so you can see this and hopefully relate: $conditions = ''; foreach ($postgroups as $id => $min_posts) { $conditions .= ' WHEN posts >= ' . $min_posts . (!empty($lastMin) ? ' AND posts <= ' . $lastMin : '') . ' THEN ' . $id; $lastMin = $min_posts; } // A big fat CASE WHEN... END is faster than a zillion UPDATE's ;). $smcFunc['db_query']('', ' UPDATE {db_prefix}members SET id_post_group = CASE ' . $conditions . ' ELSE 0 END' . ($parameter1 != null ? ' WHERE ' . (is_array($parameter1) ? 'id_member IN ({array_int:members})' : 'id_member = {int:members}') : ''), array( 'members' => $parameter1, ) ); Before I do the update, I actually have a SELECT which throws everything I need into arrays like so: $disabled_sections = array(); $positions = array(); while ($row = $smcFunc['db_fetch_assoc']($request)) { if (!isset($disabled_sections[$row['id_group']][$row['id_layout']])) $disabled_sections[$row['id_group']][$row['id_layout']] = array( 'info' => $module_info[$name], 'id_layout_position' => $row['id_layout_position'] ); // Increment the positions... if (!is_null($row['position'])) { if (!isset($positions[$row['id_layout']][$row['id_layout_position']])) $positions[$row['id_layout']][$row['id_layout_position']] = 1; else $positions[$row['id_layout']][$row['id_layout_position']]++; } else $positions[$row['id_layout']][$row['id_layout_position']] = 0; } Thanks, I know if anyone can help me here it's definitely you guys and gals... Anyways, here is my question: How do I use a CASE statement in the first code example, so that I can update all of the rows in the position column from 0 - total # of rows found, that have that id_layout value and that id_layout_position value, and continue this for all different id_layout values in that table? Can I use the arrays above somehow? I'm sure I'll have to use the id_layout and id_layout_position values for this right? But how can I do this?

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  • How can I get a list of modified records from a SQL Server database?

    - by Pixelfish
    I am currently in the process of revamping my company's management system to run a little more lean in terms of network traffic. Right now I'm trying to figure out an effective way to query only the records that have been modified (by any user) since the last time I asked. When the application starts it loads the job information and caches it locally like the following: SELECT * FROM jobs. I am writing out the date/time a record was modified ala UPDATE jobs SET Widgets=@Widgets, LastModified=GetDate() WHERE JobID=@JobID. When any user requests the list of jobs I query all records that have been modified since the last time I requested the list like the following: SELECT * FROM jobs WHERE LastModified>=@LastRequested and store the date/time of the request to pass in as @LastRequest when the user asks again. In theory this will return only the records that have been modified since the last request. The issue I'm running into is when the user's date/time is not quite in sync with the server's date/time and also of server load when querying an un-indexed date/time column. Is there a more effective system then querying date/time information?

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  • Visual Studio 2010 - Crash/Problems on the keyboard (Keys)

    - by Ph.E
    Camarades, My Visual Studio is in trouble in keyboard. I am working normally, when suddenly my keyboard loses its configuration, so where is the "" becomes "/". Someone can tell me what would be a possible solution? (Yes, I know something is hazy). Or has left some Pachter fix for problems like this. Grateful for any help. Success for all. Microsoft Visual Studio 2010 Version 10.0.30319.1 RTMRel

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  • In SQL find the combination of rows whose sum add up to a specific amount (or amt in other table)

    - by SamH
    Table_1 D_ID Integer Deposit_amt integer Table_2 Total_ID Total_amt integer Is it possible to write a select statement to find all the rows in Table_1 whose Deposit_amt sum to the Total_amt in Table_2. There are multiple rows in both tables. Say the first row in Table_2 has a Total_amt=100. I would want to know that in Table_1 the rows with D_ID 2, 6, 12 summed = 100, the rows D_ID 2, 3, 42 summed = 100, etc. Help appreciated. Let me know if I need to clarify. I am asking this question as someone as part of their job has a list of transactions and a list of totals, she needs to find the possible list of transactions that could have created the total. I agree this sounds dangerous as finding a combination of transactions that sums to a total does not guarantee that they created the total. I wasn't aware it is an np-complete problem.

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  • How to check if the sum of some records equals the difference between two other records in t-sql?

    - by Dan Appleyard
    I have a view that contains bank account activity. ACCOUNT BALANCE_ROW AMOUNT SORT_ORDER 111 1 0.00 1 111 0 10.00 2 111 0 -2.50 3 111 1 7.50 4 222 1 100.00 5 222 0 25.00 6 222 1 125.00 7 ACCOUNT = account number BALANCE_ROW = either starting or ending balance would be 1, otherwise 0 AMOUNT = the amount SORT_ORDER = simple order to return the records in the order of start balance, activity, and end balance I need to figure out a way to see if the sum of the non balance_row rows equal the difference between the ending balance and the starting balance. The result for each account (1 for yes, 0 for no) would be simply added to the resulting result set. Example: Account 111 had a starting balance of 0.00. There were two account activity records of 10.00 and -2.5. That resulted in the ending balance of 7.50. I've been playing around with temp tables, but I was not sure if there is a more efficient way of accomplishing this. Thanks for any input you may have!

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  • Foreign keys and NULL in mySQL

    - by Industrial
    Hi everyone, Can I have a column in my values table (value) referenced as a foreign key to knownValues table, and let it be NULL whenever needed, like in the example: Table: values product type value freevalue 0 1 NULL 100 1 2 NULL 25 3 3 1 NULL Table: types id name prefix 0 length cm 1 weight kg 2 fruit NULL Table: knownValues id Type name 0 2 banana Note: The types in the table values & knownValues are of course referenced into the types table. Thanks!

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  • Can you use the same Enum in multiple entities in Linq-to-SQL?

    - by Mark
    In my persistence layer, I've declared a load of Enums to represent tables containing reference data (i.e. data never changes). In Linq2SQL, I am able to set the type of an entity property to an enum type and all is well, but as soon as I set a second entity's property to use the same enum type, the Code Generator (MSLinqToSQLGenerator) start generating an empty code file. I assume that MSLinqToSQLGenerator is quietly crashing. The question is why, and are there any work-arounds? Anyone else experienced this problem?

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  • Securing database keys for client-side processing

    - by danp
    I have a tree of information which is sent to the client in a JSON object. In that object, I don't want to have raw IDs which are coming from the database. I thought of making a hash of the id and a field in the object (title, for example) or a salt, but I'm worried that this might have a serious effect on processing overhead. SELECT * FROM `things` where md5(concat(id,'some salt')) = md5('1some salt'); Is there a standard practice for obscuring IDs in this kind of situation?

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  • Why is selecting specified columns, and all, wrong in Oracle SQL?

    - by TomatoSandwich
    Say I have a select statement that goes.. select * from animals That gives a a query result of all the columns in the table. Now, if the 42nd column of the table animals is is_parent, and I want to return that in my results, just after gender, so I can see it more easily. But I also want all the other columns. select is_parent, * from animals This returns ORA-00936: missing expression. The same statement will work fine in Sybase, and I know that you need to add a table alias to the animals table to get it to work ( select is_parent, a.* from animals ani), but why must Oracle need a table alias to be able to work out the select?

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  • Is there a standard SQL Table design for overriding 'big picture' default values with lower level de

    - by RichardHowells
    Here's an example. Suppose we are trying to calculate a service charge. Say sales in the USA attract a 10 dollar charge, sales in the UK attract a 20 dollar charge So far it's easy - we are starting to imagine a table that lists charges by country. Now lets assume that Alaska and Hawaii are treated as special cases they are both 15 dollars That suggests a table with states, Alaska and Hawaii are charged at 15, but presumably we need 48 (redundant) rows all saying 10. This gives us a maintainance problem, our user only wants to type 10 once NOT 48 times. It does not sit well with the UK either. The UK does not have states. Suppose we throw in another couple of cross cutting rules. If you order by phone there is a 10% supplement on the charge. If you order via the web there is a 10% discount. But for some reason best known to the owners of the business the web/phone supplement/discount are not applied in Hawaii. It seems to me that this is quite a common kind of problem and there is probably a well known arrangement of tables to store the data. Most cases get handled by broad brush answers, but there are some very detailed low level variations that give rise to a huge number of theoretical combinations, most of which are not used.

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  • What's wrong with foreign keys?

    - by kronoz
    I remember hearing Joel mention in the podcast that he'd barely ever used a foreign key (if I remember correctly). However, to me they seem pretty vital to avoid duplication and subsequent data integrity problems throughout your database. Do people have some solid reasons as to why (to avoid a discussion in lines with SO principals)? Edit: "I've yet to have a reason to create a foreign key, so this might be my first reason to actually set up one."

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  • How to insert a value based on lookup from another table [SQL]?

    - by Shaitan00
    I need to find a way to do an INSERT INTO table A but one of the values is something that comes from a lookup on table B, allow me to illustrate. I have the 2 following tables: Table A: A1: String A2: Integer value coming from table B A3: More Data Table B: B1: String B2: Integer Value Example row of A: {"Value", 101, MoreData} Example row of B: {"English", 101} Now, I know I need to INSERT the following into A {"Value2", "English", MoreData} but obviously that won't work because it is expecting an Integer in the second column not the word "English", so I need to do a lookup in Table B first. Something like this: INSERT INTO tableA (A1, A2, A3) VALUES ("Value2", SELECT B2 FROM tableB where B1="English", MoreData); Obviously this doesn't work as-is ... Any suggestions?

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