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  • I Need Help Fixing My Small Time Sheet Table - Relational DB - SQL Server

    - by user327387
    I have a TimeSheet table as: CREATE TABLE TimeSheet ( timeSheetID employeeID setDate timeIn outToLunch returnFromLunch timeOut ); Employee will set his/her time sheet daily, i want to ensure that he/she doesn't cheat. What should i do? Should i create a column that gets date/time of the system when insertion/update happens to the table and then compare the created date/time with the time employee's specified - If so in this case i will have to create date/time column for timeIn, outToLunch, returnFromLunch and timeOut. I don't know, what do you suggest? Note: i'm concerned about tracking these 4 columns timeIn, outToLunch, returnFromLunch and timeOut

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  • Zend DB inserting relational data

    - by Wimbjorno
    I'm using the Zend Framework database relationships for a couple of weeks now. My first impression is pretty good, but I do have a question related to inserting related data into multiple tables. For a little test application I've related two tables with each other by using a fuse table. +---------------+ +---------------+ +---------------+ | Pages | | Fuse | | Prints | +---------------+ +---------------+ +---------------+ | pageid | | fuseid | | printid | | page_active | | fuse_page | | print_title | | page_author | | fuse_print | | print_content | | page_created | | fuse_locale | | ... | | ... | | ... | +---------------+ +---------------+ +---------------+ Above is an example of my DB architecture Now, my problem is how to insert related data to two separate tables and insert the two newly created ID's into the fuse table at the same time. If someone could could maybe explain or give me a topic related tutorial. I would appreciate it!

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  • Designing Relational Survey Questionnaires Database

    - by user1213055
    I'm trying to build a simple sql database for following access database. Currently there is no relationship and I just have two tables male and female with 6 sections in each form. How can I design it a better way so end user can connect to the database and analyze using STATA or SPSS ? I'm really confused whether I should create one table with all fields or break down into different tables. The database is specific to this study only so I'm not looking for a generic survey database where user can create surveys and capture them. Any feedback or suggestion is much appreciated.

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  • NoSQL vs Relational Coding Styles

    - by Chris Henry
    When building objects that make use of data stored in a RDBMS, it's normally pretty clear what you're getting back, as dictated by the tables and columns being queried. However, when dealing with NoSQL, document-based systems, it's less clear what is being retrieved. What are common methods of keeping track of structure in which data is stored?

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  • Saving Data to Relational Database (Entity Framework)

    - by sheefy
    I'm having a little bit of trouble saving data to a database. Basically, I have a main table that has associations to other tables (Example Below). Tbl_Listing ID UserID - Associated to ID in User Table CategoryID - Associated to ID in Category Table LevelID - Associated to ID in Level Table. Name Address Normally, it's easy for me to add data to the DB (using Entity Framework). However, I'm not sure how to add data to the fields with associations. The numerous ID fields just need to hold an int value that corresponds with the ID in the associated table. For example; when I try to access the column in the following manner I get a "Object reference not set to an instance of an object." error. Listing NewListing = new Listing(); NewListing.Tbl_User.ID = 1; NewListing.Tbl_Category.ID = 2; ... DBEntities.AddToListingSet(NewListing); DBEntities.SaveChanges(); I am using NewListing.Tbl_User.ID instead of NewListing.UserID because the UserID field is not available through intellisense. If I try and create an object for each related field I get a "The relationship between the two objects cannot be defined because they are attached to different ObjectContext objects." error. With this method, I am trying to add the object without the .ID shown above - example NewListing.User = UserObject. I know this should be simple as I just want to reference the ID from the associated table in the main Listing's table. Any help would be greatly appreciated. Thanks in advance, -S

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  • Moving webshop storage to NoSQL solution

    - by mare
    If you had a webshop solution based on SQL Server relational DB what would be the reasons, if any, to move to NoSQL storage ? Does it even make sense to migrate datastores that rely on relations heavily to NoSQL? If starting from scratch, would you choose NoSQL solution over relational one for a webshop project, which will, after a while, again end up with a bunch of tables like Articles, Classifications, TaxRates, Pricelists etc. and a magnitude of relations between them? What's the support like in .NET (4.0) for MongoDB or MongoDB's support for .NET 4.0? Can I count on rich code generation tools similar to EF wizard, L2SQL wizard etc. for MongoDB? Because as what I have read so far, NoSQL's are mostly suited for document storage, simpler object models. Your answer to this question will help me make the right infrastructure design decisions.

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  • Are there any other causes of this error that are NOT related to initial setup?

    - by LordScree
    I'm trying to diagnose an issue at a customer site. They are receiving the following error: A network-related or instance-specific error occurred while establishing a connection to SQL Server I've seen this a few times, but only during the initial setup - it's often caused by one of the following: The database server is turned off The network connection between the database server and the application is closed or somehow blocked (e.g. a firewall) The SQL Server instance is not set up to receive remote connections from the application server (e.g. TCP is turned off, remote connections are disabled, or the "SQL Server Browser" service is stopped/disabled) However, if I assume that no configuration changes have been made, I'm trying to postulate on what the reason might be for getting this error at a random point after the initial setup. My initial thought is: SQL Server machine has run out of resources (e.g. RAM) and is unable to accept new requests from the application server Is this a valid theory? What other possible causes are there of this error that are not related to the initial setup of the server / application connection? Or is it simply impossible that this error could occur without a configuration change having been made (either on the SQL Server side, application side, or somewhere in-between (network))? NOTE: I believe this question differs from the plethora of questions related to this error message because the application and server have been talking to each other quite happily until now (most, if not all, other questions seem to relate to initial setup).

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  • Shall i learn Assembly Language or C, to Understand how "real programming" works?

    - by Daniel Upton
    Hello, World.. I'm a web developer mostly working in Ruby and C#.. I wanna learn a low level language so i dont look like an ass infront of my (computer science expert) boss. Ive heard a lot of purist buzz about how assembly language is the only way to learn how computers actually work, but on the other hand C would probably be more useful as a language rather than just for theory. So my question is.. Would Learning C teach me enough computer science theory / low level programming to not look like a common dandy (complete tool)? Thanks! Daniel

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  • Is there a well grounded theory on backward and forward compatibility of formats, languages, grammars and vocabularies?

    - by Breton
    I have a friend who has the specific problem of building a case against the use of a custom HTML <wrapper> tag in some site's markup. Now, intuitively we can answer that use of such a tag is risky, as future HTML specs may define a wrapper tag with semantics that conflict with its use on the site. We can also appeal to a particular section of the HTML5 spec which also recommends against the use of custom tags for this reason. And while I agree with the conclusion, I find these arguments a little on the weak side, on their own. Is there some well grounded and proven theory in computer science from which we can derive this conclusion? Have programming language theorists created proofs about the properties of vocabulary versioning, or some such thing?

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  • The Next-gen Databases

    - by Randin
    I'm learning traditional Relational Databases (with PostgreSQL) and doing some research I've come across some new types of databases. CouchDB, Drizzle, and Scalaris to name a few, what is going to be the next database technologies to deal with?

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  • Database design -- does it respect 3rd NF?

    - by Flavius
    Hi I have the following relations (tables) in a relational model Person person_id, first_name, last_name, address Student person_id, matr_nr Teacher person_id, salary Lecture lecture_id, lect_name, lect_description Attendees lecture_id, person_id, date I'm wondering about the functional dependencies of Student and Teacher. Do these tables respect the 3rd normal form? Which should be the primary keys of these tables?

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  • What relationship do software Scrum or Lean have to industrial engineering concepts like theory of constraints?

    - by DeveloperDon
    In Scrum, work is delivered to customers through a series of sprints in which project work is time boxed to a fixed number of days or weeks, usually 30 days. In lean software development, the goal is to deliver as soon as possible, permitting early feedback for the next iteration. Both techniques stress the importance of workflow in which software work product does not accumulate in development awaiting release at some future date. Both permit new or refined requirements and feedback from QA and customers to be acted on with as little delay as possible based on priority. A few years ago I heard a lecture where the speaker talked briefly about a family of concepts from industrial engineering called theory of constraints. In the factory, they use an operations model based on three components: drum, buffer, and rope. The drum synchronizes work product as it flows through the system. Buffers that protect the system by holding output from one stage as it waits to be consumed by the next. The rope pulls product from one work station to the next. Historically, are these ideas part of the heritage of Scrum and Lean, or are they on a separate track? It we wanted to think about Scrum and Lean in terms of drum-buffer-rope, what are the parts? Drum = {daily scrum meeting, monthly release)? Buffer = {burn down list, source control system)? Rope = { daily meeting, constant integration server, monthly releases}? Industrial engineers define work flow in terms of different kinds of factories. I-Factories: straight pipeline. One input, one output. A-Factories: many inputs and one output. V-Factories: one input, many output products. T-Plants: many inputs, many outputs. If it applies, what kind of factory is most like Scrum or Lean and why?

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  • graph algorithms on GPU

    - by scatman
    the current GPU threads are somehow limited (memory limit, limit of data structures, no recursion...). do you think it would be feasible to implement a graph theory problem on GPU. for example vertex cover? dominating set? independent set? max clique?.... is it also feasible to have branch-and-bound algorithms on GPUs? Recursive backtracking?

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  • Balancing a Binary Tree (AVL)

    - by Gustavo Carreno
    Ok, this is another one in the theory realm for the CS guys around. In the 90's I did fairly well in implementing BST's. The only thing I could bever get my head around was the intricacy of the algorithm to balance a Binary Tree (AVL). Can you guys help me on this?

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  • How to adjust the distribution of values in a random data stream?

    - by BCS
    Given a infinite stream of random 0's and 1's that is from a biased (e.g. 1's are more common than 0's by a know factor) but otherwise ideal random number generator, I want to convert it into a (shorter) infinite stream that is just as ideal but also unbiased. Looking up the definition of entropy finds this graph showing how many bits of output I should, in theory, be able to get from each bit of input. The question: Is there any practical way to actually implement a converter that is nearly ideally efficient?

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  • How can an SQL relational database be used to model a thesaurus? [closed]

    - by Miles O'Keefe
    I would like to design a web app that functions as a simple thesaurus: a long list of words with attributes, all of which are linked to each other. This thesaurus data model can be defined as: a controlled vocabulary arranged in a known order in which equivalence, hierarchical, and associative relationships among terms are clearly displayed and identified by standardized relationship indicators. My idea so far is to have one database in which every word is a table, and every table contains all words related to that word. e.g. Thesaurus(database) - happy(table) - excited(row)|cheerful(row)|lively(row) Is there are more efficient way to store words and their relationship to other words in a relational SQL database?

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  • Which of the following relational database management systems would a company adopt (for migration), if any, MS Access, MS SQL Server or MySQL?

    - by Hassan Hagi
    Dear programmers, as part of my final year university project, I am conducting research into relational database management systems such as Microsoft Office Access 2007, Microsoft SQL Server 2008 and MySQL 5.1. The description does not need to be detailed however; I am trying to find empirical evidence and professional opinion/fact to determine which of the three databases are best suited for the required size of company (stated or unstated). OS: Microsoft windows (XP or newer) Please consider the following, but full details are not necessary: Memory management Migration Design constraints Integrity (data and others) Triggers User constraints Ease of use Performance Crash Recovery (not the operating system) Total Cost of Ownership (TCO) Also any info on Open source (to do with the three RDBMS) Thank you for your time and help. Hassan Hagi

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  • Building dynamic OLAP data marts on-the-fly

    - by DrJohn
    At the forthcoming SQLBits conference, I will be presenting a session on how to dynamically build an OLAP data mart on-the-fly. This blog entry is intended to clarify exactly what I mean by an OLAP data mart, why you may need to build them on-the-fly and finally outline the steps needed to build them dynamically. In subsequent blog entries, I will present exactly how to implement some of the techniques involved. What is an OLAP data mart? In data warehousing parlance, a data mart is a subset of the overall corporate data provided to business users to meet specific business needs. Of course, the term does not specify the technology involved, so I coined the term "OLAP data mart" to identify a subset of data which is delivered in the form of an OLAP cube which may be accompanied by the relational database upon which it was built. To clarify, the relational database is specifically create and loaded with the subset of data and then the OLAP cube is built and processed to make the data available to the end-users via standard OLAP client tools. Why build OLAP data marts? Market research companies sell data to their clients to make money. To gain competitive advantage, market research providers like to "add value" to their data by providing systems that enhance analytics, thereby allowing clients to make best use of the data. As such, OLAP cubes have become a standard way of delivering added value to clients. They can be built on-the-fly to hold specific data sets and meet particular needs and then hosted on a secure intranet site for remote access, or shipped to clients' own infrastructure for hosting. Even better, they support a wide range of different tools for analytical purposes, including the ever popular Microsoft Excel. Extension Attributes: The Challenge One of the key challenges in building multiple OLAP data marts based on the same 'template' is handling extension attributes. These are attributes that meet the client's specific reporting needs, but do not form part of the standard template. Now clearly, these extension attributes have to come into the system via additional files and ultimately be added to relational tables so they can end up in the OLAP cube. However, processing these files and filling dynamically altered tables with SSIS is a challenge as SSIS packages tend to break as soon as the database schema changes. There are two approaches to this: (1) dynamically build an SSIS package in memory to match the new database schema using C#, or (2) have the extension attributes provided as name/value pairs so the file's schema does not change and can easily be loaded using SSIS. The problem with the first approach is the complexity of writing an awful lot of complex C# code. The problem of the second approach is that name/value pairs are useless to an OLAP cube; so they have to be pivoted back into a proper relational table somewhere in the data load process WITHOUT breaking SSIS. How this can be done will be part of future blog entry. What is involved in building an OLAP data mart? There are a great many steps involved in building OLAP data marts on-the-fly. The key point is that all the steps must be automated to allow for the production of multiple OLAP data marts per day (i.e. many thousands, each with its own specific data set and attributes). Now most of these steps have a great deal in common with standard data warehouse practices. The key difference is that the databases are all built to order. The only permanent database is the metadata database (shown in orange) which holds all the metadata needed to build everything else (i.e. client orders, configuration information, connection strings, client specific requirements and attributes etc.). The staging database (shown in red) has a short life: it is built, populated and then ripped down as soon as the OLAP Data Mart has been populated. In the diagram below, the OLAP data mart comprises the two blue components: the Data Mart which is a relational database and the OLAP Cube which is an OLAP database implemented using Microsoft Analysis Services (SSAS). The client may receive just the OLAP cube or both components together depending on their reporting requirements.  So, in broad terms the steps required to fulfil a client order are as follows: Step 1: Prepare metadata Create a set of database names unique to the client's order Modify all package connection strings to be used by SSIS to point to new databases and file locations. Step 2: Create relational databases Create the staging and data mart relational databases using dynamic SQL and set the database recovery mode to SIMPLE as we do not need the overhead of logging anything Execute SQL scripts to build all database objects (tables, views, functions and stored procedures) in the two databases Step 3: Load staging database Use SSIS to load all data files into the staging database in a parallel operation Load extension files containing name/value pairs. These will provide client-specific attributes in the OLAP cube. Step 4: Load data mart relational database Load the data from staging into the data mart relational database, again in parallel where possible Allocate surrogate keys and use SSIS to perform surrogate key lookup during the load of fact tables Step 5: Load extension tables & attributes Pivot the extension attributes from their native name/value pairs into proper relational tables Add the extension attributes to the views used by OLAP cube Step 6: Deploy & Process OLAP cube Deploy the OLAP database directly to the server using a C# script task in SSIS Modify the connection string used by the OLAP cube to point to the data mart relational database Modify the cube structure to add the extension attributes to both the data source view and the relevant dimensions Remove any standard attributes that not required Process the OLAP cube Step 7: Backup and drop databases Drop staging database as it is no longer required Backup data mart relational and OLAP database and ship these to the client's infrastructure Drop data mart relational and OLAP database from the build server Mark order complete Start processing the next order, ad infinitum. So my future blog posts and my forthcoming session at the SQLBits conference will all focus on some of the more interesting aspects of building OLAP data marts on-the-fly such as handling the load of extension attributes and how to dynamically alter the structure of an OLAP cube using C#.

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  • MS Access Premiere Products Exercise

    - by rynwtts
    I am working with Microsoft Access, Premiere Products Exercises for a college course. I can't seem to get past a specific question. We are working with DBDL and E-R Diagrams. The question is here. Indicate the changes you need to make to the design of the Premiere Products database to support the following situation. A customer is not necessarily represented by a single sales rep but can be represented by several sales reps. when a customer places an order, the sales rep who gets the commission on the order must be one of the collection of sales reps who represents the customer. In the database already each customer is represented by a sales rep. Which yields a one to one relationship. I need to enable a customer to have several sales reps, and make it so that only those sales rep will be eligible for commission upon each order.

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  • Why is a FLAC encoded from a decoded MP3 bigger than the MP3?

    - by Ryan Thompson
    To be more precise than in the title, suppose I have a MP3 file that is 320 kbps. If I decompress it, then logically, all the data except for roughly 320 kilobits out of each second of audio should be redundant data, able to be compressed away. So, when I encode the decompressed file to FLAC, or any other lossless codec, why is it so much larger? On a related note, is it theoretically possible to losslessly recover the source mp3 audio from a decompressed wav? (I know the mp3 itself is lossy. I'm asking if it's possible to re-encode without any further loss.) EDIT: Let me clarify the related question, and the rationale behind it. Suppose I have a wav that was decompressed from an MP3 file (and assume I don't have the mp3 itself for some reason). If I don't want to lose any more quality, I can re-encode it with FLAC or any other lossless encoder and get a larger file just to maintain the same quality. Or, I can re-encode it to mp3 again and get the same size as the original but lose more data. Obviously, neither of these cases is ideal. I can either have the original size or the original quality, but not both (I mean the quality of the original mp3, not the original lossless source). My question is: Can we get both? Is it theoretically possible to recover the lossy compressed data from the lossy decompressed data, without losing even more? If it is possible, I could imagine a lossless compression algorithm that compresses the audio with FLAC. Then it also scans the audio for any signs of previous lossy compression, and if detected, recompresses it losslessly to the original lossy file. Then it keeps whichever file is smaller.

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  • dhcpd pool exhaustion - What's the result?

    - by jarmund
    I have a DHCP server that serves leases to several houndred, maybe up to a thousand, different clients on an average day. The pool consists of 242 IPs, and due to the highly dynamic nature of the network, it's enough 99% of the time (most devices are gone from the network in a few minutes), despite having a lease time of 3600. Now, imagine if more clients than that connect to the network during an hour. The sollution is obvious: Decrease lease time, or increase the DHCP pool, however, what i would like to know: What happens when dhcpd has exhausted the pool? Are new DHCP requests simply ignored?

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  • What if a computer with Ethernet

    - by George Nixon
    I'm just revising for an exam on Networks and Data Communications, and there's one thing I don't get about CSMA/CD and Ethernet. It's supposed to be fairly stable, for instance if a computer drops out of the network, it's not a problem like it might be in a token ring network (I think). But Ethernet works by all the other computers waiting for the currently transmitting computer to finish what it's doing, and then the others use CMSA/CD to determine who goes next. What if one computer malfunctioned and kept sending a continuous stream of data in an infinite loop? In fact, is there a standard time for pcs to transmit before they yield to others?

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