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  • Entity Framework Adding new record with foreign key constraint

    - by Brono The Vibrator
    In an effort to learn the entity framework I have created two tables in a one to many relationship. The one table (Author) has the following fields - AuthorID, FirstName, LastName. The many table (Payroll) has the following fields - PayrollID, AuthorID, Salary. I have CRUD stored procdures for insert, update and delete. What I am tying to figure-out is how to add new payroll records to the payroll table.

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  • Can't submit new object to WCF DataService because of Primary Key constraint

    - by Rob
    I've got a SQL database that uses Guid's for PK's and upon insert, it generates a NewId(). I have an EF data context setup pointing to that database with the primary keys setup with the Entity key:true, Setter:private and StoreGeneratedPattern:Identity because I want the DB to manage the keys and not have code set the PK property. I have an OData (System.Web.Data.Services.DataService) endpoint to access this data (just like: Hanselman did. I have another app that has a service reference to this service. Upon trying to create a new object from this reference (i.e. Product), the ProductId Primary Key is being defaulted to Guid.Empty when doing var serviceEntities = new ServiceEntities(serviceUri); //OData endpoint var product = new Product(); product.Name = "New Product"; serviceEntities.AddToProducts(product); serviceEntities.SaveChanges(); // error happens here When debugging, I look at the Product.ProductId property and it's set to Guid.Empty. When called SaveChanges, I do not want the ProductId field to be sent to the service. The response I get is: Error processing request stream. Property 'ProductId' is a read-only property and cannot be updated. Please make sure that this property is not present in the request payload. Is there a way to do this or what can I do to get this setup correctly and still have the DB generated the keys. Here is the same setup as the Product example above.

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  • Embedded Prolog Interpreter/Compiler for Java

    - by Sami
    I'm working on an application in Java, that needs to do some complex logic rule deductions as part of its functionality. I'd like to code my logic deductions in Prolog or some other logic/constraint programming language, instead of Java, as I believe the resulting code will be significantly simpler and more maintainable. I Googled for embedded Java implementations on Prolog, and found number of them, each with very little documentation. My (modest) selection criteria are: should be embeddable in Java (e.g. can be bundled up with my java package instead of requiring any native installations on external programs) simple interface to use from Java (for initiating deductions, inspecting results, and adding rules) come with at least a few examples on how to use it doesn't necessarely have to be Prolog, but other logic/constraint programming languages with the above criteria would suit my needs, too. What choices do I have and what are their advantages and disadvantages?

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  • Constraint Satisfaction Problem

    - by Carl Smotricz
    I'm struggling my way through Artificial Intelligence: A Modern Approach in order to alleviate my natural stupidity. In trying to solve some of the exercises, I've come up against the "Who Owns the Zebra" problem, Exercise 5.13 in Chapter 5. This has been a topic here on SO but the responses mostly addressed the question "how would you solve this if you had a free choice of problem solving software available?" I accept that Prolog is a very appropriate programming language for this kind of problem, and there are some fine packages available, e.g. in Python as shown by the top-ranked answer and also standalone. Alas, none of this is helping me "tough it out" in a way as outlined by the book. The book appears to suggest building a set of dual or perhaps global constraints, and then implementing some of the algorithms mentioned to find a solution. I'm having a lot of trouble coming up with a set of constraints suitable for modelling the problem. I'm studying this on my own so I don't have access to a professor or TA to get me over the hump - this is where I'm asking for your help. I see little similarity to the examples in the chapter. I was eager to build dual constraints and started out by creating (the logical equivalent of) 25 variables: nationality1, nationality2, nationality3, ... nationality5, pet1, pet2, pet3, ... pet5, drink1 ... drink5 and so on, where the number was indicative of the house's position. This is fine for building the unary constraints, e.g. The Norwegian lives in the first house: nationality1 = { :norway }. But most of the constraints are a combination of two such variables through a common house number, e.g. The Swede has a dog: nationality[n] = { :sweden } AND pet[n] = { :dog } where n can range from 1 to 5, obviously. Or stated another way: nationality1 = { :sweden } AND pet1 = { :dog } XOR nationality2 = { :sweden } AND pet2 = { :dog } XOR nationality3 = { :sweden } AND pet3 = { :dog } XOR nationality4 = { :sweden } AND pet4 = { :dog } XOR nationality5 = { :sweden } AND pet5 = { :dog } ...which has a decidedly different feel to it than the "list of tuples" advocated by the book: ( X1, X2, X3 = { val1, val2, val3 }, { val4, val5, val6 }, ... ) I'm not looking for a solution per se; I'm looking for a start on how to model this problem in a way that's compatible with the book's approach. Any help appreciated.

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  • NSPredicate as a constraint solver?

    - by Felixyz
    I'm working on a project which includes some slightly more complex dynamic layout of interface elements than what I'm used to. I always feel stupid writing complex code that checks if so-and-so is close to such-and-such and in that case move it x% in some direction, etc. That's just not how programming should be done. Programming should be as declarative as possible! Precisely because what I'm going to do is fairly simple, I thought it would be a good opportunity to try something new, and I thought of using NSPredicate as a simple constraints solver. I've only used NSPredicate for very simple tasks so far, but I know that it capable of much more. Are there any ideas, experiences, examples, warnings, insights that could be useful here? I'll give a very simple example so there will be something concrete to answer. How could I use NSPredicate to solve the following constraints: viewB.xmid = (viewB.leftEdge + viewB.width) / 2 viewB.xmid = max(300, viewA.rightEdge + 20 + viewB.width/2) ("viewB should be horizontally centered on coordinate 300, unless its left edge gets within 20 pixels of viewB's right edge, in which case viewA's left edge should stay fixed at 20 pixels to the right of viewB's right edge and viewA's horizontal center get pushed to the right.") viewA.rightEdge and viewB.width can vary, and those are the 'input variables'. EDIT: Any solution would probably have to use the NSExpression method -(id)expressionValueWithObject:(id)object context:(NSMutableDictionary *)context. This answer is relevant.

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  • Violation of PRIMARY KEY constraint 'PK_

    - by abhi
    hi am trying to write a code in which i need to perform a update but on primary keys how do i achieve it i have written the following code: kindly look at it let me know where m wrong Protected Sub rgKMSLoc_UpdateCommand(ByVal source As Object, ByVal e As Telerik.Web.UI.GridCommandEventArgs) Handles rgKMSLoc.UpdateCommand Try KAYAReqConn.Open() If TypeOf e.Item Is GridEditableItem Then Dim strItemID As String = CType(e.Item.FindControl("hdnID"), HiddenField).Value Dim strrcmbLocation As String = CType(e.Item.FindControl("rcmbLocation"), RadComboBox).SelectedValue Dim strKubeLocation As String = CType(e.Item.FindControl("txtKubeLocation"), TextBox).Text Dim strCSVCode As String = CType(e.Item.FindControl("txtCSVCode"), TextBox).Text SQLCmd = New SqlCommand("SELECT * FROM MstKMSLocKubeLocMapping WHERE LocationID= '" & rcmbLocation.SelectedValue & "'", KAYAReqConn) Dim dr As SqlDataReader dr = SQLCmd.ExecuteReader If dr.HasRows Then lblMsgWarning.Text = "<font color=red>""User ID Already Exists" Exit Sub End If dr.Close() SQLCmd = New SqlCommand("UPDATE MstKMSLocKubeLocMapping SET LocationID=@Location,KubeLocation=@KubeLocation,CSVCode=@CSVCode WHERE LocationID = '" & strItemID & "'", KAYAReqConn) SQLCmd.Parameters.AddWithValue("@Location", Replace(strrcmbLocation, "'", "''")) SQLCmd.Parameters.AddWithValue("@KubeLocation", Replace(strKubeLocation, "'", "''")) SQLCmd.Parameters.AddWithValue("@CSVCode", Replace(strCSVCode, "'", "''")) SQLCmd.Parameters.AddWithValue("@Status", "A") SQLCmd.ExecuteNonQuery() lblMessageUpdate.Text = "<font color=blue>""Record Updated SuccessFully" SQLCmd.Dispose() rgKMSLoc.Rebind() End If Catch ex As Exception Response.Write(ex.ToString) Finally KAYAReqConn.Close() End Try End Sub this is my designer page' Location: ' / ' DataSourceID="dsrcmbLocation" DataTextField="Location" DataValueField="LocationID" Height="150px" Kube Location: ' Class="forTextBox" MaxLength="4" onkeypress="return filterInput(2,event);" CSV Code: ' Class="forTextBox" MaxLength="4" onkeypress="return filterInput(2,event);" <tr class="tableRow"> <td colspan="2" align="center" class="tableCell"> <asp:ImageButton ID="btnUpdate" runat="server" CommandName="Update" CausesValidation="true" ValidationGroup="Update" ImageUrl="~/Images/update.gif"></asp:ImageButton> <asp:ImageButton ID="btnCancel" runat="server" CausesValidation="false" CommandName="Cancel" ImageUrl="~/Images/No.gif"></asp:ImageButton> </td> </tr> </table> </FormTemplate> </EditFormSettings> Locationid is my primary key

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  • MySQL ignores the NOT NULL constraint

    - by Marga Keuvelaar
    I have created a table with NOT NULL constraints on some columns in MySQL. Then in PHP I wrote a script to insert data, with an insert query. When I omit one of the NOT NULL columns in this insert statement I would expect an error message from MySQL, and I would expect my script to fail. Instead, MySQL inserts empty strings in the NOT NULL fields. In other omitted fields the data is NULL, which is fine. Could someone tell me what I did wrong here? I'm using this table: CREATE TABLE IF NOT EXISTS tblCustomers ( cust_id int(11) NOT NULL AUTO_INCREMENT, custname varchar(50) NOT NULL, company varchar(50), phone varchar(50), email varchar(50) NOT NULL, country varchar(50) NOT NULL, ... date_added timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP, PRIMARY KEY (cust_id) ) ; And this insert statement: $sql = "INSERT INTO tblCustomers (custname,company) VALUES ('".$customerName."','".$_POST["CustomerCompany"]."')"; $res = mysqli_query($mysqli, $sql);

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  • declaring constraint to consider prog logic

    - by shantanuo
    I can open a trip only once but can close it multiple times. I can not declare the Trip_no + status as primary key since there can be multiple entries while closing the trip. Is there any way that will assure me that a trip number is opened only once? For e.g. there should not be the second row with "Open" status for trip No. 3 since it is already there in the following table. Trip No | Status 1 Open 1 Close 1 Close 2 Open 2 Close 3 Open 3 Close 3 Close 3 Close 3 Close

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  • i need a query to retrieve the following constraint

    - by ANITHA
    I have the following tables and fields: +------------------+ +-------------------+ +---------------+ | Request | | RequestItem | | Item | +------------------+ +-------------------+ +---------------+ | + Requester_Name | | + Request_No | | + Item | +------------------+ +-------------------+ +---------------+ | + Request_No | | + Item | +------------------+ +-------------------+ I would like to filter the items which are selected under a particular request number, along with a specific requester name. How might I go about doing this?

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  • Travelling Salesman Problem Constraint Representation

    - by alex25
    Hey! I read a couple of articles and sample code about how to solve TSP with Genetic Algorithms and Ant Colony Optimization etc. But everything I found didn't include time (window) constraints, eg. "I have to be at customer x before 12am)" and assumed symmetry. Can somebody point me into the direction of some sample code or articles that explain how I can add constraints to TSP and how I can represent those in code. Thanks!

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  • Problem in inferring instances that have integer cardinality constraint

    - by Mikae Combarado
    Hello, I have created an RDF/OWL file using Protege 4.1 alpha. I also created a defined class in Protege called CheapPhone. This class has a restriction which is shown below : (hasPrice some integer[< 350]) Whenever, a price of a phone is below 350, it is inferred as CheapPhone. There is no problem for inferring this in Protege 4.1 alpha. However, I cannot infer this using Jena. I also created a defined class called SmartPhone. This class also has a restriction which is shown below : (has3G value true) and (hasInternet value true) Whenever, a phone has 3G and Internet, it is inferred as SmartPhone. In this situation, there is no problem inferring this in both Protege and Jena. I have started to think that there is a problem in default inference engine of Jena. The code that I use in Java is below : Reasoner reasoner = ReasonerRegistry.getOWLReasoner(); reasoner = reasoner.bindSchema(ontModel); OntModelSpec ontModelSpec = OntModelSpec.OWL_MEM_MINI_RULE_INF; ontModelSpec.setReasoner(reasoner); // Create ontology model with reasoner support // ontModel was created and read before, so I don't share the code in order // not to create garbage here OntModel model = ModelFactory.createOntologyModel(ontModelSpec, ontModel); OntClass sPhone = model.getOntClass(ns + "SmartPhone"); ExtendedIterator s = sPhone.listInstances(); while(s.hasNext()) { OntResource mp = (OntResource)s.next(); System.out.println(mp.getURI()); } This code works perfectly and returns me the instances, but when I change the code below and make it appropriate for CheapPhone, it doesn't return anything. OntClass sPhone = model.getOntClass(ns + "CheapPhone"); Am I doing something wrong ?

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  • mysql ignores not null constraint?

    - by Marga Keuvelaar
    I have created a table with NOT NULL constraints on some columns in MySQL. Then in PHP I wrote a script to insert data, with an insert query. When I omit one of the NOT NULL columns in this insert statement I would expect an error message from MySQL, and I would expect my script to fail. Instead, MySQL inserts empty strings in the NOT NULL fields. In other omitted fields the data is NULL, which is fine. Could someone tell me what I did wrong here? I'm using this table: CREATE TABLE IF NOT EXISTS tblCustomers ( cust_id int(11) NOT NULL AUTO_INCREMENT, custname varchar(50) NOT NULL, company varchar(50), phone varchar(50), email varchar(50) NOT NULL, country varchar(50) NOT NULL, ... date_added timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP, PRIMARY KEY (cust_id) ) ; And this insert statement: $sql = "INSERT INTO tblCustomers (custname,company) VALUES ('".$customerName."','".$_POST["CustomerCompany"]."')"; $res = mysqli_query($mysqli, $sql);

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  • Constraint to array dimension in C language

    - by Summer_More_More_Tea
    int KMP( const char *original, int o_len, const char *substring, int s_len ){ if( o_len < s_len ) return -1; int k = 0; int cur = 1; int fail[ s_len ]; fail[ k ] = -1; while( cur < s_len ){ k = cur - 1; do{ if( substring[ cur ] == substring[ k ] ){ fail[ cur ] = k; break; }else{ k = fail[ k ] + 1; } }while( k ); if( !k && ( substring[ cur ] != substring[ 0 ] ) ){ fail[ cur ] = -1; }else if( !k ){ fail[ cur ] = 0; } cur++; } k = 0; cur = 0; while( ( k < s_len ) && ( cur < o_len ) ){ if( original[ cur ] == substring[ k ] ){ cur++; k++; }else{ if( k == 0 ){ cur++; }else{ k = fail[ k - 1 ] + 1; } } } if( k == s_len ) return cur - k; else return -1; } This is a KMP algorithm I once coded. When I reviewed it this morning, I find it strange that an integer array is defined as int fail[ s_len ]. Does the specification requires dimesion of arrays compile-time constant? How can this code pass the compilation? By the way, my gcc version is 4.4.1. Thanks in advance!

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  • Python combinations no repeat by constraint

    - by user2758113
    I have a tuple of tuples (Name, val 1, val 2, Class) tuple = (("Jackson",10,12,"A"), ("Ryan",10,20,"A"), ("Michael",10,12,"B"), ("Andrew",10,20,"B"), ("McKensie",10,12,"C"), ("Alex",10,20,"D")) I need to return all combinations using itertools combinations that do not repeat classes. How can I return combinations that dont repeat classes. For example, the first returned statement would be: tuple0, tuple2, tuple4, tuple5 and so on.

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  • Consolidating values in a junction table

    - by senloe
    I have the following schema: Parcels Segments SegmentsParcels ========= ========== ================= ParcelID SegmentID ParcelID ... Name SegmentID ... id A user of the data wants to consolidate Segments.Names and gave me a list of current Segment.Names mapped to new Segment.Names (all of which currently exist). So now I have this list in a temporary table with the currentID and newID to map to. What I want to do is update the SegmentID in SegmentsParcels based on this map. I could use the statement: update SegmentParcels set segmentID = [newID] from newsegments where segmentID = currentid but this will create some duplicates I have a unique constraint on ParcelID and SegmentID in SegmentParcels. What is the best way to go about this? I considered removing the constraint and then dealing with removing the duplicates (which I did at one point and could probably do again) but I was hoping there was a simpler way.

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  • Violation of primary key constraint, multiple users

    - by MC.
    Lets say UserA and UserB both have an application open and are working with the same type of data. UserA inserts a record into the table with value 10 (PrimaryKey='A'), UserB does not currently see the value UserA entered and attempts to insert a new value of 20 (PrimaryKey='A'). What I wanted in this situation was a DBConcurrencyException, but instead what I have is a primary key violation. I understand why, but I have no idea how to resolve this. What is a good practice to deal with such a circumstance? I do not want to merge before updating the database because I want an error to inform the user that multiple users updated this data.

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  • Generate all permutations with sort constraint

    - by Moos Hueting
    Hi! I have a list consisting of other lists and some zeroes, for example: x = [[1, 1, 2], [1, 1, 1, 2], [1, 1, 2], 0, 0, 0] I would like to generate all the combinations of this list while keeping the order of the inner lists unchanged, so [[1, 1, 2], 0, 0, [1, 1, 1, 2], [1, 1, 2], 0] is fine, but [[1, 1, 1, 2], [1, 1, 2], 0, 0, [1, 1, 2], 0] isn't. I've got the feeling that this should be fairly easy in Python, but I just don't see it. Could somebody help me out?

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  • Oracle - Trigger to check constraint before insert

    - by user1816507
    i would like to create a simple trigger to check a stored variable from a table. if the value of the variable is '1', then approve the insertion else if the value of the variable is '2', then prompt error message. CREATE OR REPLACE TRIGGER approval BEFORE INSERT ON VIP REFERENCING OLD AS MEMBER FOR EACH ROW DECLARE CONDITION_CHECK NUMBER; BEGIN SELECT CONDITION INTO CONDITION_CHECK FROM MEMBER; IF CONDITION_CHECK = '2' THEN RAISE_APPLICATION_ERROR (-20000, ' UPGRADE DENIED!'); END IF; END; But this trigger disable all the entries even when the condition value is '1'.

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  • Shuffling a list with a constraint

    - by 500
    Preparing a new psychophysic experiment, I have 48 original stimuli displayed 4 times (4 conditions). Resulting in 192 trials. Trying to randomize the order of presentation during the experiment, I need to maximize the distance between the 4 display of the same original stimuli. Please Consider : Table[{j, i}, {j, Range[48]}, {i, Range[4]}] Where j is the original stimuli number and i the condition Output Sample : {{1, 1}, {1, 2}, {1, 3}, {1, 4}, {2, 1}, {2, 2}, {2, 3}, {2, 4}, ... {47, 1}, {47, 2}, {47, 3},{47, 4}, {48, 1}, {48, 2}, {48, 3}, {48, 4}} How could I shuffle the order of presentation of those 192 items, maximizing the distance between identical item with regard to j the original stimuli number ?

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  • Check constraint on table lookup

    - by bzamfir
    Hi, I have a table, department , with several bit fields to indicate department types One is Warehouse (when true, indicate the department is warehouse) And I have another table, ManagersForWarehouses with following structure: ID autoinc WarehouseID int (foreign key reference DepartmentID from departments) ManagerID int (foreign key reference EmployeeID from employees) StartDate EndDate To set new manager for warehouse, I insert in this table with EndDate null, and I have a trigger that sets EndDate for previous record for that warehouse = StartDate for new manager, so a single manager appears for a warehouse at a certain time. I want to add two check constraints as follows, but not sure how to do this do not allow to insert into ManagersForWarehouses if WarehouseID is not marked as warehouse Do not allow to uncheck Warehouse if there are records in ManagersForWarehouses Thanks

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  • Why isn't the new() generic constraint satisfied by a class with optional parameters in the construc

    - by Joshua Flanagan
    The following code fails to compile, producing a "Widget must be a non-abstract type with a public parameterless constructor" error. I would think that the compiler has all of the information it needs. Is this a bug? An oversight? Or is there some scenario where this would not be valid? public class Factory<T> where T : new() { public T Build() { return new T(); } } public class Widget { public Widget(string name = "foo") { Name = name; } public string Name { get; set; } } public class Program { public static void Main() { var widget = new Widget(); // this is valid var factory = new Factory<Widget>(); // compiler error } }

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  • Advance Query with Join

    - by user1462589
    I'm trying to convert a product table that contains all the detail of the product into separate tables in SQL. I've got everything done except for duplicated descriptor details. The problem I am having all the products have size/color/style/other that many other products contain. I want to only have one size or color descriptor for all the items and reuse the "ID" for all the product which I believe is a Parent key to the Product ID which is a ...Foreign Key. The only problem is that every descriptor would have multiple Foreign Keys assigned to it. So I was thinking on the fly just have it skip figuring out a Foreign Parent key for each descriptor and just check to see if that descriptor exist and if it does use its Key for the descriptor. Data Table PI Colo Sz OTHER 1 | Blue | 5 | Vintage 2 | Blue | 6 | Vintage 3 | Blac | 5 | Simple 4 | Blac | 6 | Simple =================================== Its destination table is this =================================== DI Description 1 | Blue 2 | Blac 3 | 5 4 | 6 6 | Vintage 7 | Simple ============================= Select Data.Table Unique.Data.Table.Colo Unique.Data.Table.Sz Unique.Data.Table.Other ======================================= Then the dual part of the questions after we create all the descriptors how to do a new query and assign the product ID to the descriptors. PI| DI 1 | 1 1 | 3 1 | 4 2 | 1 2 | 3 2 | 4 By figuring out how to do this I should be able to duplicate this pattern for all 300 + columns in the product. Some of these fields are 60+ characters large so its going to save a ton of space. Do I use a Array?

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