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  • What is the best way to keep database data encrypted with user passwords?

    - by Dan Sosedoff
    Let's say an application has really specific data which belongs to a user, and nobody is supposed to see it except the owner. I use MySQL database with DataMapper ORM mapper. The application is written in Ruby on Sinatra. Application behavior: User signs up for an account. Creates username and password. Logs into his dashboard. Some fields in specific tables must be protected. Basically, I'm looking for auto-encryption for a model properties. Something like this: class Transaction include DataMapper::Resource property :id, Serial property :value, String, :length => 1024, :encrypted => true ... etc ... belongs_to :user end I assume that encryption/decryption on the fly will cause performance problems, but that's ok. At least if that works - I'm fine. Any ideas how to do this?

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  • Online DATAFILE MOVE in Oracle Database 12c

    - by Ulrike Schwinn (DBA Community)
    Einige Operationen im Datenbankumfeld können nicht nur offline sondern auch online durchgeführt werden. Ein wichtiges Kennzeichen einer Online Operation ist dabei, dass Abfragen und DML Operationen während des Ablaufs der Operation (beispielsweise einer Reorganisation) ohne Unterbrechung weiter laufen können. Je nach einplanbarer Maintenance Zeit ist es daher durchaus wünschenswert, gewisse Operationen online durchzuführen. Generell gibt es in jedem Datenbankrelease einige Erweiterungen im Umfeld von Online Operationen. Besonders im aktuellen Release 12c gibt es eine Vielzahl neuer Operationen zu diesem Thema.Während der ersten 12c Veranstaltungen fand besonders das Kommando "DATAFILE ONLINE MOVE" besondere Aufmerksamkeit bei vielen Kunden. Aus diesem Grund wird im aktuellen Tipp dazu eine kleine Einführung gegeben.  Mehr dazu erfahren Sie hier. 

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  • Allocation of IP Address in Ad hoc systems

    - by Kasturi
    Me and my friends play Age of Empires every weekend and create an Ad-hoc network each time before playing. But each time we all get the SAME IP Address even if a new ad-hoc network is created. Is this something to do with the Game's algorithm or does the laptop remember our previous IP Address. EDIT: What is the algorithm that is used to distribute the IP Addresses? If the algorithm uses random function how come same IP addresses are being allocated.

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  • Embedded systems linux

    - by bhaskaragr29
    I want to make final year project so i want a two way interface device one connect to server and other connect to ouput display device..like television. whats are the rquirements i need....and how do i this.

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  • Meshing different systems of keys together in XML Schema

    - by Tom W
    Hello SO, I'd like to ask people's thoughts on an XSD problem I've been pondering. The system I am trying to model is thus: I have a general type that represents some item in a hypothetical model. The type is abstract and will be inherited by all manner of different model objects, so the model is heterogeneous. Furthermore, some types exist only as children of other types. Objects are to be given an identifier, but the scope of uniqueness of this identifier varies. Some objects - we will call them P (for Parent) objects - must have a globally unique identifier. This is straightforward and can use the xs:key schema element. Other objects (we can call them C objects, for Child) are children of a P object and must have an identifier that is unique only in the scope of that parent. For example, object P1 has two children, object C1 and C2, and object P2 has one child, object C3. In this system, the identifiers given could be as follows: P1: 1 (1st P object globally) P2: 2 (2nd P object globally) C1: 1 (1st C object of P1) C2: 2 (2nd C object of P1) C3: 1 (1st C object of P2) I want the identity syntax of every model object to be identical if possible, therefore my first pass at implementing is to define a single type: <xs:complexType name="ModelElement"> <xs:attribute name="IDMode" type="IdentityMode"/> <xs:attribute name="Identifier" type="xs:string"/> </xs:complexType> where the IdentityMode is an enumerated value: <xs:simpleType name="IdentityMode"> <xs:restriction base="xs:string"> <xs:enumeration value="Identified"/> <xs:enumeration value="Indexed"/> <xs:enumeration value="None"/> </xs:restriction> </xs:simpleType> Here "Identified" signifies a global identifier, and "Indexed" indicates an identifier local only to the parent. My question is, how do I enforce these uniqueness conditions using unique, key or other schema elements based on the IdentityMode property of the given subtype of ModelElement?

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  • Understanding omission failure in distributed systems

    - by karthik A
    The following text says this which I'm not able to quite agree : client C sends a request R to server S. The time taken by a communication link to transport R over the link is D. P is the maximum time needed by S to recieve , process and reply to R. If omission failure is assumed ; then if no reply to R is received within 2(D+P) , then C will never recieve a reply to R . Why is the time here 2(D+P). As I understand shouldn't it be 2D+P ?

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  • How can I load a SQLITE database from a buffer with the C API ?

    - by rockeye
    Hello, I am trying to load a database from the memory instead of opening a .sqlite file. I have read the C/C++ API reference but I can not find the proper method. The buffer I am trying to load is simply an sqlite file loaded in memory. I just want to use this buffer (a const char* array) without using the filesystem (I could have saved this buffer in a file, then load the file, but no). First, I create a memory DB : mErrorCode = sqlite3_open_v2(":memory:", &mSqlDatabase, lMode, NULL); This returns SQLITE_OK, then I tried to use the buffer as a statement and call preparev2(MyDB, MyBufferData, MyBufferLength, MyStatement, NULL) but it's not really a statement, and it returns an error. Same result if I call directly exec(MyDB, MyBufferData, NULL, NULL, NULL); I guess there is an appropriate method to achieve this as it might be common to load a DB from a stream or from decrypted data... Thanks.

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  • Multiuser's impact on Access Database

    - by SilentRage47
    Can someone explain to me how are effected the performances of an Access 2003 DB when it's used by a lot (30) of users on the same LAN? I'm working on a vb6 project with this access 2003 DB wich performs ok on my local PC, but it's terrible when used across 20-30 users. It's there something I can do to improve performance? How can I understand what's the cause of this degradation in performance?

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  • sqlite error :/* SQL error or missing database */

    - by user262325
    Hello everyone I have a project in which I stored sqlite database file "data.sqlite3" to 'Group'&files'-'resource' Below are my viewcontroller source codes //-myviewcontroller.h #import "sqlite3.h" #define kFilename @"data.sqlite3" //myviewcontroller.m -(NSString *)dataFilePath { NSArray *paths = NSSearchPathForDirectoriesInDomains( NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDirectory = [paths objectAtIndex:0]; return [documentsDirectory stringByAppendingPathComponent:kFilename]; } -(void)f { if (sqlite3_open([[self dataFilePath] UTF8String],&database)!=SQLITE_OK) //dataFilePath returns ///Users/interdev/Library/Application Support/iPhone Simulator/User/Applications/095C6E05-4EAE-4817-883E-A72E39D439E0/Documents/data.sqlite3 { sqlite3_close(database); NSAssert(0,@"Failed to open database");//no problem } NSString *query = @"SELECT * FROM table1 ORDER BY ROW";//table1 is table name sqlite3_stmt *statement; NSInteger v=sqlite3_prepare_v2( database, [query UTF8String], -1, &statement, nil); NSString *zs= [NSString stringWithFormat:@"%d",v]; NSLog(@" The buttontitile is %@ ",zs); if ( v == SQLITE_OK) { // ... } I checked value of v in log, it always is 1 #define SQLITE_ERROR 1 /* SQL error or missing database */ I do not know why this happened.

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  • system-wide hook for 64-bit operating systems

    - by strDisplayName
    Hey everybody I want to perform a system-wide hook (using SetWindowHook) on a 64bit operating system. I know that 64bit processes (= proc64) can load only 64bit dlls (= dll64) and 32bit processes (= proc32) can load only 32bit dlls (= dll32). Currently I am planning to call SetWindowHook twice, once with dll32 and once with dll64, expecting that proc64s will load dll64 and proc32s will load dll32 (while dll32 for proc64s and dll64 for proc32s will fail). Is that the correct way to do that, or is there a "more correct" way to do that? Thanks! :-)

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  • Can it be a good idea to create a new table for each client of a webapp?

    - by Will
    This is semi-hypothetical, and as I've no experience in dealing with massive database tables, I have no idea if this is horrible for some reason. On to the situation: Imagine a web based application - lets say accounting software - which has 20,000 clients and each client has 1000+ entries in a table. That's 20 million rows which I know can certainly slow down complex queries. In a case like this, does it make more sense to create a new table in the database for each client? How do databases react to having 20k (or more!) tables?

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  • How can I efficiently retrieve a large number of database settings as PHP variables?

    - by Steven
    Currently all of my script's settings are located in a PHP file which I 'include'. I'm in the process of moving these settings (about 100) to a database table called 'settings'. However I'm struggling to find an efficient way of retrieving all of them into the file. The settings table has 3 columns: ID (autoincrements) name value Two example rows might be: 1 admin_user john 2 admin_email_address [email protected] The only way I can think of retrieving each setting is like this: $result = mysql_query("SELECT value FROM settings WHERE name = 'admin_user'"); $row = mysql_fetch_array($result); $admin_user = $row['value']; $result = mysql_query("SELECT value FROM settings WHERE name = 'admin_email_address'"); $row = mysql_fetch_array($result); $admin_email_address = $row['value']; etc etc Doing it this way will take up a lot of code and will likely be slow. Is there a better way? Thanks.

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  • GDI+ on 64bit systems

    - by LaZe
    Our system uses a lot of large Bitmaps (System.Drawing.Bitmap) and sometimes we run out of memory and gets a "Parameter is not valid" error. This makes sense, since it can be difficult to allocate large continuous chunk of memory. So the question is... If we upgraded the system to 64bit, would this problem go away?

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  • How do I display and calculate numbers from a database on iPhone?

    - by JoshD
    I am new to designing apps and have a basic understand of Ob-C and how everything works. What I would like to do is have two tabs, one is a home screen that displays numbers and percentages that are entered on the second tab. The user will be able to store that information and refer back to it and update it. What is the best way to complete that math from the database to the "home screen"? Any tutorials, advice is great! Thanks.

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  • How does Google store search trends in backend?

    - by Achshar
    Google trends shows what query has been searched how many times and some other properties of the said query. But how is this data stored in a database? Storing a new row for every search does not seem right. They also tell the query on a time graph, so they must have some way to look for individual searches made by users, but the number of queries they get every day, it does not feel right that they would store every search in a database row along with a time-stamp. This does not apply to just Google trends or Google in general but any other big site that gets awful number of queries and then has tools to see them in depth. I am not an expert on this but I am interested to know some high level structure of how things work behind the scenes.

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  • Dynamic access to tables from another database inside an user function

    - by Alberto Martinez
    I have an user defined table function in SQL Server that aggregate data from several tables including a couple of tables of another database. That is done hardcoding the name of the database in the queries, but we want to make the database name configurable (because our databases usually share the server with the databases of other applications). I tried to construct a dynamic query string inside the function using the database name that is stored in a configuration table, but: When I tried exec(@sqlStatement) SQL Server said that execute string is not allowed inside a function. Then I tried exec sp_executesql @sqlStatement and the function was created, but when you execute it SQL Server says that inside a function you can only run extended functions and procedures. So the question is: is possible create a function or stored procedure that access a table in another database without having to recreate the function when the database name is different? TIA.

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  • One Database or Ten?

    - by merrillaldrich
    In my career to date I’ve worked as a DBA for mainly “buy don’t build” scenarios. One advantage - and hair-graying problem, if I am honest - has been that I think I’ve seen upward of one or two hundred different ISV-provided applications’ SQL Server databases. It’s a great learning opportunity, as I can see successes and failures in a large variety of designs, and sort of “fast-forward” to version five or eight of a given design pattern to see things like whether it scales, or has storage problems,...(read more)

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  • safe structures embedded systems

    - by user405633
    I have a packet from a server which is parsed in an embedded system. I need to parse it in a very efficient way, avoiding memory issues, like overlapping, corrupting my memory and others variables. The packet has this structure "String A:String B:String C". As example, here the packet received is compounded of three parts separated using a separator ":", all these parts must be accesibles from an structure. Which is the most efficient and safe way to do this. A.- Creating an structure with attributes (partA, PartB PartC) sized with a criteria based on avoid exceed this sized from the source of the packet, and attaching also an index with the length of each part in a way to avoid extracting garbage, this part length indicator could be less or equal to 300 (ie: part B). typedef struct parsedPacket_struct { char partA[2];int len_partA; char partB[300];int len_partB; char partC[2];int len_partC; }parsedPacket; The problem here is that I am wasting memory, because each structure should copy the packet content to each the structure, is there a way to only save the base address of each part and still using the len_partX.

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  • database independent coding framework options?

    - by statirasystems
    Background: I have not programmed in a while besides doing VBA and a little VB.NET. So please forgive my language use. I'm green and have a head cold. I am reading all I can now, but I have no programming circles to draw from. The information I am providing is to help guide you to what I am looking for. I am not confident I can ask the question properly. Story: I have four different projects that I am starting. Obviously I won't be working on all at the same time however they each will have similar needs and be inter related. They are as follows: Desktop Environment/System User Interface - basically a product that runs on major computers via mono or .net that unifies the look and functions. In the context of the up coming question it would be able to directly access data of various types. It would work in tandum with my office suite, system manager, and network application framework. Office Suite - technically it would not be a suite since I will be doing it from one interfacel except for the Communications Application. As far as the question, it will need to be able to link to various data sources for storing files and using, manipulating, and presenting information. System Manager - an intellegent system to manage and administer the entire network and all equipment. As far as the question, needs to be able to access data for archiving and and for accessing it's own settings stored in various formats, sql or xml. Network Application Framework - A complete system that can be used for ERP, CRM, CMS, Errata, File Management, and so on. As to the question to be able to access it's own or interlink with existing applications. Requirement: C#, Simplifies and reduces coding, use the same code to access diffent databases(ie MySQL, MS SQL, ACCESS, XML, ...), Mono would be nice but not a must, Question: What librarys, frameworks, or other options would be able to help with this? Is there a good resource to guide me? I don't want arguing over what is best, just information to help me further understand and make an educated decision.

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  • How to design a database schema for storing text in multiple languages?

    - by stach
    We have a PostgreSQL database. And we have several tables which need to keep certain data in several languages (the list of possible languages is thankfully system-wide defined). For example lets start with: create table blah (id serial, foo text, bar text); Now, let's make it multilingual. How about: create table blah (id serial, foo_en text, foo_de text, foo_jp text, bar_en text, bar_de text, bar_jp text); That would be good for full-text search in Postgres. Just add a tsvector column for each language. But is it optimal? Maybe we should use another table to keep the translations? Like: create table texts (id serial, colspec text, obj_id int, language text, data text); Maybe, just maybe, we should use something else - something out of the SQL world? Any help is appreciated.

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  • PHP class data implementation

    - by Bakanyaka
    I'm studying OOP PHP and have watched two tutorials that implement user login\registration system as an example. But implementation varies. Which way will be more correct one to work with data such as this? Load all data retrieved from database as array into a property called something like _data on class creation and further methods operate with this property Create separate properties for each field retrieved from database, on class creation load all data fields into respective properties and operate with that properties separately? Then let's say I want to create a method that returns a list of all users with their data. Which way is better? Method that returns just an array of userdata like this: Array([0]=>array([id] => 1, [username] => 'John', ...), [1]=>array([id] => 2, [username] => 'Jack', ...), ...) Method that creates a new instance of it's class for each user and returns an array of objects

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  • Normalize database or not? Read only MyISAM table, performance is the main priority (MySQL)

    - by hello
    I'm importing data to a future database that will have one, static MyISAM table (will only be read from). I chose MyISAM because as far as I understand it's faster for my requirements (I'm not very experienced with MySQL / SQL at all). That table will have various columns such as ID, Name, Gender, Phone, Status... and Country, City, Street columns. Now the question is, should I create tables (e.g Country: Country_ID, Country_Name) for the last 3 columns and refer to them in the main table by ID (normalize...[?]), or just store them as VARCHAR in the main table (having duplicates, obviously)? My primary concern is speed - since the table won't be written into, data integrity is not a priority. The only actions will be selecting a specific row or searching for rows that much a certain criteria. Would searching by the Country, City and/or Street columns (and possibly other columns in the same search) be faster if I simply use VARCHAR?

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