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  • Using an ORM with a database that has no defined relationships?

    - by Ahmad
    Consider a database(MSSQL 2005) that consists of 100+ tables which have primary keys defined to a certain degree. There are 'relationships' between tables, however these are not enforced with foreign key constraints. Consider the following simplified example of typical types of tables I am dealing with. The are clear relations between the User and City and Province tables. However, they key issues is the inconsistent data types in the tables and naming conventions. User: UserRowId [int] PK Name [varchar(50)] CityId [smallint] ProvinceRowId [bigint] City: CityRowId [bigint] PK CityDescription [varchar(100)] Province: ProvinceId [int] PK ProvinceDesc [varchar(50)] I am considering a rewrite of the application (in ASP.net MVC) that uses this data source as is similar in design to MVC storefront. However I am going through a proof of concept phase and this is one of the stumbling blocks I have come across. What are my options in terms of ORM choice that can be easily used and why? Should I even be considering an ORM? (The reason I ask this is that most explanations and tutorials all work with relatively cleanly designed existing databases, or newly created ones when compared to mine. I am thus having a very hard time trying to find a way forward with this problem) There is a huge amount of existing SQL queries, would a datamappper(eg IBatis.net) be more suitable since we could easily modify them to work and reuse the investment already made? I have found this question on SO which indicates to me that an ORM can be used - however I get the impression that this a question of mapping? Note: at the moment, the object model is not clearly defined as it was non-existent. The existing system pretty much did almost everything in SQL or consisted of overly complicated, and numerous queries to complete fucntionality. I am pretty much a noob and have zero experience around ORMs and MVC - so this an awesome learning curve I am on.

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  • How would you structure your entity model for storing arbitrary key/value data with different data t

    - by Nathan Ridley
    I keep coming across scenarios where it will be useful to store a set of arbitrary data in a table using a per-row key/value model, rather than a rigid column/field model. The problem is, I want to store the values with their correct data type rather than converting everything to a string. This means I have to choose either a single table with multiple nullable columns, one for each data type, or a set of value tables, one for each data type. I'm also unsure as to whether I should use full third normal form and separate the keys into a separate table, referencing them via a foreign key from the value table(s), or if it would be better to keep things simple and store the string keys in the value table(s) and accept the duplication of strings. Old/bad: This solution makes adding additional values a pain in a fluid environment because the table needs to be modified regularly. MyTable ============================ ID Key1 Key2 Key3 int int string date ---------------------------- 1 Value1 Value2 Value3 2 Value4 Value5 Value6 Single Table Solution This solution allows simplicity via a single table. The querying code still needs to check for nulls to determine which data type the field is storing. A check constraint is probably also required to ensure only one of the value fields contains non-nulll data. DataValues ============================================================= ID RecordID Key IntValue StringValue DateValue int int string int string date ------------------------------------------------------------- 1 1 Key1 Value1 NULL NULL 2 1 Key2 NULL Value2 NULL 3 1 Key3 NULL NULL Value3 4 2 Key1 Value4 NULL NULL 5 2 Key2 NULL Value5 NULL 6 2 Key3 NULL NULL Value6 Multiple-Table Solution This solution allows for more concise purposing of each table, though the code needs to know the data type in advance as it needs to query a different table for each data type. Indexing is probably simpler and more efficient because there are less columns that need indexing. IntegerValues =============================== ID RecordID Key Value int int string int ------------------------------- 1 1 Key1 Value1 2 2 Key1 Value4 StringValues =============================== ID RecordID Key Value int int string string ------------------------------- 1 1 Key2 Value2 2 2 Key2 Value5 DateValues =============================== ID RecordID Key Value int int string date ------------------------------- 1 1 Key3 Value3 2 2 Key3 Value6 How do you approach this problem? Which solution is better? Also, should the key column be separated into a separate table and referenced via a foreign key or be should it be kept in the value table and bulk updated if for some reason the key name changes?

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  • What are the list of Patterns and Principals the programmer must/should know?

    - by pang
    I have been doing code for a few years and still feeling that my knowledge still not broad enough to become a professional. I have studied some books related to Design Pattern but I know there are many others. So could anyone list the one which you think it is good to learn to become a better programmer and more professional? Programming Languages I work on : C# , Ruby, Javascript

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  • What Patterns Should I Consider For a Html Widget Generator?

    - by DaveDev
    I'm looking to see if I can design a HtmlHelper extension method that will generate the Html for different types of widgets I want to produce. Each different type of widget implements functionality to get and prepare any data it needs to render. Can anyone suggest any patterns I could refer to for approaches to take? I know there are probably frameworks available that will do this for me, but I thought I'd give it a try anyway. Any points of advice? Thanks

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  • What do you call the concept of dynamic data definition?

    - by DJTripleThreat
    Maybe this is simpler and more straightforward then what I'm thinking but I can't seem to find this concept on google anywhere. The concept is this: You have a table in a database and the table has a specified number of columns. However, it has been asked of me by previous clients that there also be a set of dynamic user defined columns that can be added on the fly. What is this concept called and is it considered a design pattern?

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  • JavaScript Key Codes

    - by Jonathan Wood
    I'm working with a JavaScript routine I didn't write. It is called from a text box's onkeydown attribute to prevent unwanted keystrokes. The first argument is apparently not used. The second argument is a list of characters that should be allowed. function RestrictChars(evt, chars) { var key; var keychar; if (window.event) key = window.event.keyCode; else if (e) key = e.which; else return true; keychar = String.fromCharCode(key); if ((key == null) || (key == 0) || (key == 8) || (key == 9) || (key == 13) || (key == 27)) // Control key return true; else if (((chars).indexOf(keychar) > -1)) return true; else return false; } This seems to work for alpha-numeric characters. However, characters such as . and / cause this function to return false, even when these characters are included in the chars parameter. For example, if the . key is pressed, key is set to 190, and keychar gets set to the "3/4" character. Can anyone see how this was meant to work and/or why it doesn't? I don't know enough about JavaScript to see what it's trying to do.

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  • Guidance for Workflow type applications

    - by UpTheCreek
    Hi, I'm looking for best practices and resources regarding design of workflow based applications. E.g.Best practice/guidance for: How best to represent business object 'states' (position in workflow) How to approach logging of transition between workflow states State transition rules I'm using .NET, but am rather looking for general guidance I'm sorry that this is a bit general, I'm just hoping some people will have some experiences to share.

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  • A way to return multiple return values from a method: put method inside class representing return value. Is it a good design?

    - by john smith optional
    I need to return 2 values from a method. My approach is as follows: create an inner class with 2 fields that will be used to keep those 2 values put the method inside that class instantiate the class and call the method. The only thing that will be changed in the method is that in the end it will assign those 2 values to the fields of the instance. Then I can address those values by referencing to the fields of that object. Is it a good design and why?

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  • Error Message: Primary Slave Drive - ATAPI Incompatible

    - by Jaleel Dwight
    So I recently switched towers and now, all of a sudden, I'm getting this error message as soon as I boot my system. The error message reads "Primary Slave Drive - ATAPI Incompatible". This has really been frustrating since there's NO Primary Slave Drive even installed in my computer!! I have one hard drive installed which is recognized as the Primary Master & a DVD Drive which is recognized as the Secondary Master. My old system ran flawlessly. I'm beginning to think maybe my motherboard is bugging out cuz I fail to understand how it can be telling me that a "nonexistent" drive is incompatible. Any suggestions??

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  • Primary domain controller has crashed, secondary does not log in

    - by Hosm
    Hi everybody, I had a primary domain controller on machine A and a secondary one on machine B in my AD domain. Due to some hardware/software problems, I decided to migrate the role of primary domain controller to machine B. Unfortunately, machine A has totally crashed and does not boot. Now I can not even log in to machine B (which itself was a controller in the domain). I need to log into machine B then choose it as the primary controller. I already have synced DNS and AD info. when machine A was alive. Anyone can provide an idea?

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  • Only three primary partitions?

    - by ctype.h
    As everyone probably knows, Windows allows a drive to have four primary partitions, one of which may be active. However, I have only three primary partitions. I shrunk one and created a fourth partition so I could install Windows 8 on it, but Disk Management only allows it to be a logical partition. Why might this be the case? If I cannot convert it to a primary partition, is it advisable to install Windows on a logical partition? If so, is hibernation supported?

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  • How to find the entity with the greatest primary key?

    - by simpatico
    I've an entity LearningUnit that has an int primary key. Actually, it has nothing more. Entity Concept has the following relationship with it: @ManyToOne @Size(min=1,max=7) private LearningUnit learningUnit; In a constructor of Concept I need to retrieve the LearningUnit with the greatest primary key. If no LearningUnit exists yet I instantiate one. I then set this.learningUnit to the retrieved/instantied. Finally, I call the empty constructor of Concept in a try-catch block, to have the entitymanager do the cardinality check. If an exception is thrown (I expect one in the case that already another 7 Concepts are referring to the same LearningUnit. In that case, I case instantiate a new LearningUnit with a new greater primary key. Please, also point out, if any, clear pitfalls in my outlined algorithm above.

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  • SQL SERVER – Four Posts on Removing the Bookmark Lookup – Key Lookup

    - by pinaldave
    In recent times I have observed that not many people have proper understanding of what is bookmark lookup or key lookup. Increasing numbers of the questions tells me that this is something developers are encountering every single day but have no idea how to deal with it. I have previously written three articles on this subject. I want to point all of you looking for further information on the same post. SQL SERVER – Query Optimization – Remove Bookmark Lookup – Remove RID Lookup – Remove Key Lookup SQL SERVER – Query Optimization – Remove Bookmark Lookup – Remove RID Lookup – Remove Key Lookup – Part 2 SQL SERVER – Query Optimization – Remove Bookmark Lookup – Remove RID Lookup – Remove Key Lookup – Part 3 SQL SERVER – Interesting Observation – Execution Plan and Results of Aggregate Concatenation Queries In one of my recent class we had in depth conversation about what are the alternative of creating covering indexes to remove the bookmark lookup. I really want to this question open to all of you and see what community thinks about the same. Is there any other way then creating covering index or included index to remove his expensive keylookup? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Backup and Restore, SQL Index, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQLAuthority News, SQLServer, T SQL, Technology

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  • Domain-Driven Design

    Domain-Driven Design is the way to build/design your application when you are focused on the Domain Model, when you do not depend on Infrastructure and when your Developers talk on the same language with Customers.

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  • OBIEE 11.1.1 - BI Design Best Practices Whitepaper V1.2

    - by Nicolas Barasz
    Oracle BI Principles. Repository design best practices. Dashboards and reports design best practices. 10g Upgrade considerations. This new version includes 40 more slides than the previous one. Multiple new best practices specific to 11g and a lot of new information about upgrade from 10g. Click here to download (Right click or option-click the link and choose "Save As..." to download this pdf file)

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  • Combo/Input LOV displaying non-reference key value

    - by [email protected]
    Its a very common use-case of LOV that we want to diplay a non key value in the LOV but store the key value in the DB. I had to do the same in a sample application I was building. During implementation of this, I realized that there are multiple ways to achieve this.I am going to describe each of these below.Example : Lets take an example of our classic HR schema. I have 2 tables Employee and Department where Dno is the foreign key attribute in Employee that references Department table.I want to create a LOV for Deparment such that the List always displays Dname instead of Dno. However when I update it, it it should update the reference key Dno.To achieve this I had 3 alternative1) Approach 1 :Create a composite VO and add the attributes from Department into Employee using a join.Refer the blog http://andrejusb.blogspot.com/2009/11/defining-lov-on-reference-attribute-in.htmlPositives :1. Easy to implement and use.2. We can use this attribute directly in queries defined on new attribute i.e If i have to display this inside query panel.Negative : We have to create an additional Join on the VO.Ex:SELECT Employees.EMPLOYEE_ID,        Employees.FIRST_NAME,        Employees.LAST_NAME,        Employees.EMAIL,        Employees.PHONE_NUMBER,       Department.Dno,        Department.DnameFROM EMPLOYEES Employees, Department Department WHERE Employees.Dno = Department .Dno2) Approach 2 :

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  • What's up with LDoms: Part 9 - Direct IO

    - by Stefan Hinker
    In the last article of this series, we discussed the most general of all physical IO options available for LDoms, root domains.  Now, let's have a short look at the next level of granularity: Virtualizing individual PCIe slots.  In the LDoms terminology, this feature is called "Direct IO" or DIO.  It is very similar to root domains, but instead of reassigning ownership of a complete root complex, it only moves a single PCIe slot or endpoint device to a different domain.  Let's look again at hardware available to mars in the original configuration: root@sun:~# ldm ls-io NAME TYPE BUS DOMAIN STATUS ---- ---- --- ------ ------ pci_0 BUS pci_0 primary pci_1 BUS pci_1 primary pci_2 BUS pci_2 primary pci_3 BUS pci_3 primary /SYS/MB/PCIE1 PCIE pci_0 primary EMP /SYS/MB/SASHBA0 PCIE pci_0 primary OCC /SYS/MB/NET0 PCIE pci_0 primary OCC /SYS/MB/PCIE5 PCIE pci_1 primary EMP /SYS/MB/PCIE6 PCIE pci_1 primary EMP /SYS/MB/PCIE7 PCIE pci_1 primary EMP /SYS/MB/PCIE2 PCIE pci_2 primary EMP /SYS/MB/PCIE3 PCIE pci_2 primary OCC /SYS/MB/PCIE4 PCIE pci_2 primary EMP /SYS/MB/PCIE8 PCIE pci_3 primary EMP /SYS/MB/SASHBA1 PCIE pci_3 primary OCC /SYS/MB/NET2 PCIE pci_3 primary OCC /SYS/MB/NET0/IOVNET.PF0 PF pci_0 primary /SYS/MB/NET0/IOVNET.PF1 PF pci_0 primary /SYS/MB/NET2/IOVNET.PF0 PF pci_3 primary /SYS/MB/NET2/IOVNET.PF1 PF pci_3 primary All of the "PCIE" type devices are available for SDIO, with a few limitations.  If the device is a slot, the card in that slot must support the DIO feature.  The documentation lists all such cards.  Moving a slot to a different domain works just like moving a PCI root complex.  Again, this is not a dynamic process and includes reboots of the affected domains.  The resulting configuration is nicely shown in a diagram in the Admin Guide: There are several important things to note and consider here: The domain receiving the slot/endpoint device turns into an IO domain in LDoms terminology, because it now owns some physical IO hardware. Solaris will create nodes for this hardware under /devices.  This includes entries for the virtual PCI root complex (pci_0 in the diagram) and anything between it and the actual endpoint device.  It is very important to understand that all of this PCIe infrastructure is virtual only!  Only the actual endpoint devices are true physical hardware. There is an implicit dependency between the guest owning the endpoint device and the root domain owning the real PCIe infrastructure: Only if the root domain is up and running, will the guest domain have access to the endpoint device. The root domain is still responsible for resetting and configuring the PCIe infrastructure (root complex, PCIe level configurations, error handling etc.) because it owns this part of the physical infrastructure. This also means that if the root domain needs to reset the PCIe root complex for any reason (typically a reboot of the root domain) it will reset and thus disrupt the operation of the endpoint device owned by the guest domain.  The result in the guest is not predictable.  I recommend to configure the resulting behaviour of the guest using domain dependencies as described in the Admin Guide in Chapter "Configuring Domain Dependencies". Please consult the Admin Guide in Section "Creating an I/O Domain by Assigning PCIe Endpoint Devices" for all the details! As you can see, there are several restrictions for this feature.  It was introduced in LDoms 2.0, mainly to allow the configuration of guest domains that need access to tape devices.  Today, with the higher number of PCIe root complexes and the availability of SR-IOV, the need to use this feature is declining.  I personally do not recommend to use it, mainly because of the drawbacks of the depencies on the root domain and because it can be replaced with SR-IOV (although then with similar limitations). This was a rather short entry, more for completeness.  I believe that DIO can usually be replaced by SR-IOV, which is much more flexible.  I will cover SR-IOV in the next section of this blog series.

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  • How To Get Website Design Inspiration?

    How to get Website Design Inspiration? When it comes to finding inspiration for your website designs it can be a tricky and sometimes time consuming process. I have designed numerous sites in the pa... [Author: Adie Price - Web Design and Development - May 11, 2010]

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  • Responsive Design: Media query fix for IE10 on Windows Phone 8

    - by ihaynes
    Originally posted on: http://geekswithblogs.net/ihaynes/archive/2013/07/01/responsive-design-media-query-fix-for-ie10-on--windows.aspxThe version of IE10 on Windows Phone 8 apparently has a bug which results in media queries not seeing the correct device width.This post from Devhammer explains all.http://devhammer.net/responsive-design-fix-for-windows-phone-8-device-adaptationI'd not noticed this on the WP8 Emulator which proves yet again that testing on real devices is essential.

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  • Professional Logos Design Process

    Briefly the professional logos design process on LogoStudies.com consists of: 1) studying the niche, theme and style. We learn about your niche, see it?s main points and according to that we think o... [Author: Matas Baranauskas - Web Design and Development - April 06, 2010]

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  • Outsource Web Design Firm in India

    If somebody says that India does not have good web design firms, then chances are that either you would suggest him to do a good research on the country and its technological landscape or you will sl... [Author: John Anthony - Web Design and Development - May 18, 2010]

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  • How to Choose a Web Design Company

    There are certain things that you should take into consideration, if you want to choose an apt Web Design Company, which would fulfill your business requirements. In the first instance, you should ca... [Author: Andrew Burt - Web Design and Development - June 06, 2010]

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