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  • SQL Average Data Based on Distance

    - by jsmith
    I'm pretty new to SQL. I have a database with records based on road/milepoints. My goal is to get an average value every 52.8 ft along the road. My related table has data every 15 ft, this table of course has a foreign key relating it to the primary table. If I wanted to pull out the average value every 52.8 ft, along a given milepost, how would I go about this? Example Data: RecID Begin_MP End_MP 100 0 0.56 RecID MP Value1 Value2 100 0 159 127.7 100 0.003 95.3 115.3 100 0.006 82.3 107 100 0.009 56.5 74.5 100 0.011 58.1 89.1 100 0.014 95.2 78.8 100 0.017 108.9 242.5 100 0.02 71.8 73.3 100 0.023 84.1 80.2 100 0.026 65.5 66.1 100 0.028 122 135.8 100 0.031 99.9 230.7 100 0.034 95.7 111.5 100 0.037 127.3 74.3 100 0.04 140.7 543.1 The first Data is an example of a Road. The second subset of data are the values I need to query out every 52.8 ft. Thank you

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  • Input array is longer than the number of columns in this table

    - by Adam
    I've recently started to use SQLite and began to integrate it into a C# project I'm working on. However, randomly my project will throw the exception: Input array is longer than the number of columns in this table I'm having a hard time trying the trace the problem because it seems to be thrown on a random basis. DataTable table = new DataTable(); //exception is thrown here table = Global.db.ExecuteQuery("SELECT * FROM vm_manager"); Some of the data that gets returned from this query is as follows: http://i.imgur.com/9rlLN.png If anyone has any advice, I'd be grateful. EDIT: I'm unable to show the execute query function as it resides inside a dll from the following sql lite wrapper http://www.codeproject.com/KB/database/cs_sqlitewrapper.aspx

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  • Representing Sparse Data in PostgreSQL

    - by Chris S
    What's the best way to represent a sparse data matrix in PostgreSQL? The two obvious methods I see are: Store data in a single a table with a separate column for every conceivable feature (potentially millions), but with a default value of NULL for unused features. This is conceptually very simple, but I know that with most RDMS implementations, that this is typically very inefficient, since the NULL values ususually takes up some space. However, I read an article (can't find its link unfortunately) that claimed PG doesn't take up data for NULL values, making it better suited for storing sparse data. Create separate "row" and "column" tables, as well as an intermediate table to link them and store the value for the column at that row. I believe this is the more traditional RDMS solution, but there's more complexity and overhead associated with it. I also found PostgreDynamic, which claims to better support sparse data, but I don't want to switch my entire database server to a PG fork just for this feature. Are there any other solutions? Which one should I use?

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  • Inserting Large volume of data in SQL Server 2005

    - by Manjoor
    We have a application (written in c#) to store live stock market price in the database (SQL Server 2005). It insert about 1 Million record in a single day. Now we are adding some more segment of market into it and the no of records would be double (2 Millions/day). Currently the average record insertion per second is about 50, maximum is 450 and minimum is 0. To check certain conditions i have used service broker (asynchronous trigger) on my price table. It is running fine at this time(about 35% CPU utilization). Now i am planning to create a in memory dataset of current stock price. we would like to do some simple calculations. I want to know different views of members on this. Please provide your way of dealing with such situation.

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  • Can Microsoft store three-valued fields in a single bit?

    - by fenomas
    I'm completely ignorant of SQL/databases, but I was chatting with a friend who does a lot of database work about how some databases use a "boolean" field that can take a value of NULL in addition to true and false. Regarding this, he made a comment along these lines: "To Microsoft's credit, they have never referred to that kind of field as a boolean, they just call it a bit. And it's a true bit - if you have eight or fewer bit fields in a record, it only requires one byte to store them all." Naturally that seems impossible to me - if the field can hold three values you're not going to fit eight of them into a byte. My friend agreed that it seemed odd, but begged ignorance of the low-level internals and said that so far as he knew, such fields can hold three values when viewed from the SQL side, and it does work out to require a byte of storage. I imagine one of us has a wire crossed. Can anyone explain what's really going on here?

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  • Sequence numbers best practice

    - by Abdullah Jibaly
    What's the best practice or well known methods to implement sequence numbers for business entities such as invoices, purchase orders, job numbers, etc? I want to be able to save the latest value in the database and be able to set it programatically. Is it OK to use a table for this purpose that has a SEQUENCE_NAME, SEQUENCE_NUMBER tuple? I know some databases have a first class sequence type but others (eg, MySQL) do not so it's not something I want to rely on. If a table is used to hold these sequences what is the right way to get and increment them in a synchronized fashion to ensure no data inconsistencies arise?

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  • merging two duplicate contacts/ColdFusion

    - by jil
    having to do with data integrity - I maintain a coldfusion database at a small shop that keeps addresses of different contacts. These contacts sometimes contain notes in them. When you are merging two duplicate contacts, one may be created in 2002 and one in 2008. If the contact in 2002 has notes prior to 2008, my question would be does it matter if you merge these contacts and keep the 2008 contact's ID number? Would that affect the data integrity or create any sort of issues with the notes earlier than 2008? I hope I've accurately described my scenario, as I am not familiar with the proper technical terms. I really appreciate the help sir!

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  • How do I read Unicode characters from an MS Access 2007 database through Java?

    - by Peter
    In Java, I have written a program that reads a UTF8 text file. The text file contains a SQL query of the SELECT kind. The program then executes the query on the Microsoft Access 2007 database and writes all fields of the first row to a UTF8 text file. The problem I have is when a row is returned that contains unicode characters, such as "?". These characters show up as "?" in the text file. I know that the text files are read and written correctly, because a dummy UTF8 character ("?") is read from the text file containing the SQL query and written to the text file containing the resulting row. The UTF8 character looks correct when the written text file is opened in Notepad, so the reading and writing of the text files are not part of the problem. This is how I connect to the database and how I execute the SQL query: ---- START CODE Connection c = DriverManager.getConnection("jdbc:odbc:Driver={Microsoft Access Driver (*.mdb, *.accdb)};DBQ=C:/database.accdb;Pwd=temp"); ResultSet r = c.createStatement().executeQuery(sql); ---- END CODE I have tried making a charSet property to the Connection but it makes no difference: ---- START CODE Properties p = new Properties(); p.put("charSet", "utf-8"); p.put("lc_ctype", "utf-8"); p.put("encoding", "utf-8"); Connection c = DriverManager.getConnection("...", p); ---- END CODE Tried with "utf8"/"UTF8"/"UTF-8", no difference. If I enter "UTF-16" I get the following exception: "java.lang.IllegalArgumentException: Illegal replacement". Been searching around for hours with no results and now turn my hope to you. Please help! I also accept workaround suggestions. =) What I want to be able to do is to make a Unicode query (for example one that searches for posts that contain the "?" character) and to have results with Unicode characters receieved and saved correctly. Thank you!

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  • Oracle TNS problems ?

    - by persistence
    I have an error ? My pl/Sql Developer says my oracle database cannot find the service descriptor But when I Do a check the listener I get this error. LSNRCTL> start Starting tnslsnr: please wait... Service OracleOraDb10g_home1TNSListener already running. TNS-12560: TNS:protocol adapter error TNS-00530: Protocol adapter error LSNRCTL> status Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP TNS-12541: TNS:no listener TNS-12560: TNS:protocol adapter error TNS-00511: No listener 32-bit Windows Error: 61: Unknown error Please I have a deadline for these evening. Please help.

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  • Best way to store large dataset in SQL Server?

    - by gary
    I have a dataset which contains a string key field and up to 50 keywords associated with that information. Once the data has been inserted into the database there will be very few writes (INSERTS) but mostly queries for one or more keywords. I have read "Tagsystems: performance tests" which is MySQL based and it seems 2NF appears to be a good method for implementing this, however I was wondering if anyone had experience with doing this with SQL Server 2008 and very large datasets. I am likely to initially have 1 million key fields which could have up to 50 keywords each. Would a structure of keyfield, keyword1, keyword2, ... , keyword50 be the best solution or two tables keyid keyfield | 1 | | M keyid keyword Be a better idea if my queries are mostly going to be looking for results that have one or more keywords?

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  • Methods for ensuring security between users in multi-user applications

    - by Emilio
    I'm writing a multiuser application (.NET - C#) in which each user's data is separated from the others and there is no data that's common between users. It's critical to ensure that no user has access to another user's data. What are some approaches for implementing security at the database level and/or in the application architecture to to accomplish this? For example (and this is totally made up - I'm not suggesting it's a good or bad approach) including a userID column in all data tables might be an approach. I'm developing the app in C# (asp.net) and SQL Server 2008. I'm looking for options that are are either native in the tools I'm using or general patterns.

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  • Server authorization with MD5 and SQL.

    - by Charles
    I currently have a SQL database of passwords stored in MD5. The server needs to generate a unique key, then sends to the client. In the client, it will use the key as a salt then hash together with the password and send back to the server. The only problem is that the the SQL DB has the passwords in MD5 already. Therefore for this to work, I would have to MD5 the password client side, then MD5 it again with the salt. Am I doing this wrong, because it doesn't seem like a proper solution. Any information is appreciated.

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  • free sql script to get a list of countries, provinces/states and their cities.

    - by reggie
    I am working on a registration page for a php website as mysql as the backend database. I need a sql script to insert the list of countries with their associated provinces and the provinces with their associated cities. I need all the countries, provinces and cities all over the world which are related to each other. I can get the individual list of countries, provinces and cities but there is no list that relates them together.. any help appreciated.. thanks in advance.

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  • SQL Server - Query Short-Circuiting?

    - by Sam Schutte
    Do T-SQL queries in SQL Server support short-circuiting? For instance, I have a situation where I have two database and I'm comparing data between the two tables to match and copy some info across. In one table, the "ID" field will always have leading zeros (such as "000000001234"), and in the other table, the ID field may or may not have leading zeros (might be "000000001234" or "1234"). So my query to match the two is something like: select * from table1 where table1.ID LIKE '%1234' To speed things up, I'm thinking of adding an OR before the like that just says: table1.ID = table2.ID to handle the case where both ID's have the padded zeros and are equal. Will doing so speed up the query by matching items on the "=" and not evaluating the LIKE for every single row (will it short circuit and skip the LIKE)?

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  • Change an access Primary key with relationships

    - by DiegoMaK
    I have a database in access 2007 accdb extension , there are more or less 30-40 tables with related primary key "local_number". it is a text primary key with 10 lenght. How can I change the length of this primary key to 30 WITHOUT delete previosly all the 30 relationship. 2,A similar question. I need add a compose primary key to my PK "local_number". I need Add a "Date" as composed PK. Then access just allow this if I first delete all relationships. How can Avoid this warning and change my PK ignoring this message.

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  • Why & When should I use SPARSE COLUMN? (SQL SERVER 2008)

    - by priyanka.sarkar
    After going thru some tutorials on SQL SERVER 2008's new feature SPARSE COLUMN, I have found that it doesn't take any space if the column value is 0 or null but when there is a value, it takes 4 times the space a regular(non sparse) column holds. If my understanding is correct, then why I will go for that at the time of database design? And if I use that, then at what situation so I be? Also out of curiosity, how come no space get's reserve when a column is defined as sparse column(I mean to say, what is the internal implementation for that) Thanks in advance

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  • Best way to store sales tax information

    - by Seph
    When designing a stock management database system (sales / purchases) what would be the best way to store the various taxes and other such amounts? A few of the fields that could be saved are: Unit price excluding tax Unit price including tax Tax per item Total excluding tax (rounded to 2 decimals) Total including tax (rounded to 2 decimals) Total tax (rounded to 2 decimals) Currently the most reasonable solution so far is storing down (roughly) item, quantity, total excluding tax (rounded) and the total tax (rounded). Can anyone suggest some better way of storing this details for a generic system? Also, given the system needs to be robust, what should be done if there were multiple tax values (eg: state and city) which might need to be separated, in this case a separate table would be in order, but would it be considered excessive to just have a rowID and some taxID mapping to a totalTax column?

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  • Non-Relational DBMS Design Resources

    - by Matt Luongo
    Hey guys, As a personal project, I'm looking to build a rudimentary DBMS. I've read the relevant sections in Elmasri & Navathe (5ed), but could use a more focused text. The rub is that I want to play with novel non-relational data models. While a lot of E&N was great- indexing implementation details in particular- the more advanced DBMS implementation was only targeted to a relational model. I could also use something a bit more practical and detail-oriented, with real-world recommendations. I'd like to defer staring at DBMS source for a while if I can. Any ideas?

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  • Are there any small scale, durable document/object databases?

    - by Joe Doyle
    I have a few .Net projects that would benefit from using a document/object database opposed to a relational one. I think that db4o would be a good choice, but we're not sure how much the cost is. I'd love to use MongoDB but it's design isn't for small scale, single server applications. Are there other options out there that I just haven't run across for small scale applications? EDIT: So is this a space that doesn't have a good solution, yet? Are there no small scale & durable document databases? Would my best choice be to use MongoDB and set the --syncdelay option set to 1?

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  • Does DB2 have an "insert or update" statement?

    - by Mikael Eriksson
    From my code (Java) I want to ensure that a row exists in the database (DB2) after my code is executed. My code now does a select and if no result is returned it does an insert. I really don't like this code since it exposes me to concurrency issuses when running in a multi-threaded environment. What I would like to do is to put this logic in DB2 instead of in my Java code. Does DB2 have an "insert-or-update" statement? Or anything like it that I can use? For example: insertupdate into mytable values ('myid') Another way of doing it would probably be to allways do the insert and catch "SQL-code -803 primary key already exists", but I would like to avoid that if possible.

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  • Analysis services with non normalized table

    - by Uwe
    I have a table with several million rows. Each row represents a user session. There is a column called user which is not unique. There can be multiple sessions per user. I want to use Analysis services to get me the additional properties per user. Example: How many users (unique!) had a session longer than x minutes. How is that possible without changing the database. Note: there is no lookup-table and I cannot create one. What I am able of at the moment is to ask how many sessions were longer then x minutes.

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  • What stage of normalization is this? (moving repeating data into separate table)

    - by Sergio
    Hi There, I have noticed that when designing a database I tend to shift any repeating sets of data into a separate table. For example, say I had a table of people, with each person living in a state. I would then move these repeating states into a separate table and reference them with foreign keys. However, what if I was not storing any more data about states. I would then have a table with StateID and State in. Is this action correct? State is dependant on the primary key of the users table, so does shifting it into its own table help with anything? Thanks,

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  • How to handle request-wise DB transactions in ASP.NET MVC?

    - by Dario Solera
    I'm using SubSonic 3.0 (SimpleRepository) to handle database access in my ASP.NET MVC 1.0 application. It would be nice to handle a transaction for every web request, committing if everything went smooth and rolling back in case of exception. Is this possible? If so, how? I know this topic has been discussed many times, but I just couldn't find a satisfactory answer. I have built my own solution (create a TransactionScope in the controller, then commit/rollback in OnActionExecuted), but it turns out to be very unreliable.

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  • MySQL - Finding time overlaps

    - by Jude
    Hi, I have 2 tables in the database with the following attributes: Booking ======= booking_id booking_start booking_end resource_booked =============== booking_id resource_id The second table is an associative entity between "Booking" and "Resource" (i.e., 1 booking can contain many resources). Attributes booking_start and booking_end are timestamps with date and time in it. May I know how I might be able to find out for each resource_id (resource_booked) if the date/time overlaps or clashes with other bookings of similar resource_id? I was doodling the answer on paper, pictorially, to see if it might help me visualize how I could solve this and I got this: Joining the 2 tables (Booking, Booked_resource) into one table with the 4 attributes needed. Follow the answer suggested here : http://stackoverflow.com/questions/689458/find-overlapping-date-time-rows-within-one-table I did step 1 but step 2 is leaving me baffled! I would really appreciate any help on this! Thanks!

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  • Views performance in MySQL

    - by Gianluca Bargelli
    I am currently writing my truly first PHP Application and i would like to know how to project/design/implement MySQL Views properly; In my particular case User data is spread across several tables (as a consequence of Database Normalization) and i was thinking to use a View to group data into one large table: CREATE VIEW `Users_Merged` ( name, surname, email, phone, role ) AS ( SELECT name, surname, email, phone, 'Customer' FROM `Customer` ) UNION ( SELECT name, surname, email, tel, 'Admin' FROM `Administrator` ) UNION ( SELECT name, surname, email, tel, 'Manager' FROM `manager` ); This way i can use the View's data from the PHP app easily but i don't really know how much this can affect performance. For example: SELECT * from `Users_Merged` WHERE role = 'Admin'; Is the right way to filter view's data or should i filter BEFORE creating the view itself? (I need this to have a list of users and the functionality to filter them by role).

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