Search Results

Search found 4565 results on 183 pages for 'nhibernate mapping'.

Page 52/183 | < Previous Page | 48 49 50 51 52 53 54 55 56 57 58 59  | Next Page >

  • Inheritance Mapping Strategies with Entity Framework Code First CTP5: Part 3 – Table per Concrete Type (TPC) and Choosing Strategy Guidelines

    - by mortezam
    This is the third (and last) post in a series that explains different approaches to map an inheritance hierarchy with EF Code First. I've described these strategies in previous posts: Part 1 – Table per Hierarchy (TPH) Part 2 – Table per Type (TPT)In today’s blog post I am going to discuss Table per Concrete Type (TPC) which completes the inheritance mapping strategies supported by EF Code First. At the end of this post I will provide some guidelines to choose an inheritance strategy mainly based on what we've learned in this series. TPC and Entity Framework in the Past Table per Concrete type is somehow the simplest approach suggested, yet using TPC with EF is one of those concepts that has not been covered very well so far and I've seen in some resources that it was even discouraged. The reason for that is just because Entity Data Model Designer in VS2010 doesn't support TPC (even though the EF runtime does). That basically means if you are following EF's Database-First or Model-First approaches then configuring TPC requires manually writing XML in the EDMX file which is not considered to be a fun practice. Well, no more. You'll see that with Code First, creating TPC is perfectly possible with fluent API just like other strategies and you don't need to avoid TPC due to the lack of designer support as you would probably do in other EF approaches. Table per Concrete Type (TPC)In Table per Concrete type (aka Table per Concrete class) we use exactly one table for each (nonabstract) class. All properties of a class, including inherited properties, can be mapped to columns of this table, as shown in the following figure: As you can see, the SQL schema is not aware of the inheritance; effectively, we’ve mapped two unrelated tables to a more expressive class structure. If the base class was concrete, then an additional table would be needed to hold instances of that class. I have to emphasize that there is no relationship between the database tables, except for the fact that they share some similar columns. TPC Implementation in Code First Just like the TPT implementation, we need to specify a separate table for each of the subclasses. We also need to tell Code First that we want all of the inherited properties to be mapped as part of this table. In CTP5, there is a new helper method on EntityMappingConfiguration class called MapInheritedProperties that exactly does this for us. Here is the complete object model as well as the fluent API to create a TPC mapping: public abstract class BillingDetail {     public int BillingDetailId { get; set; }     public string Owner { get; set; }     public string Number { get; set; } }          public class BankAccount : BillingDetail {     public string BankName { get; set; }     public string Swift { get; set; } }          public class CreditCard : BillingDetail {     public int CardType { get; set; }     public string ExpiryMonth { get; set; }     public string ExpiryYear { get; set; } }      public class InheritanceMappingContext : DbContext {     public DbSet<BillingDetail> BillingDetails { get; set; }              protected override void OnModelCreating(ModelBuilder modelBuilder)     {         modelBuilder.Entity<BankAccount>().Map(m =>         {             m.MapInheritedProperties();             m.ToTable("BankAccounts");         });         modelBuilder.Entity<CreditCard>().Map(m =>         {             m.MapInheritedProperties();             m.ToTable("CreditCards");         });                 } } The Importance of EntityMappingConfiguration ClassAs a side note, it worth mentioning that EntityMappingConfiguration class turns out to be a key type for inheritance mapping in Code First. Here is an snapshot of this class: namespace System.Data.Entity.ModelConfiguration.Configuration.Mapping {     public class EntityMappingConfiguration<TEntityType> where TEntityType : class     {         public ValueConditionConfiguration Requires(string discriminator);         public void ToTable(string tableName);         public void MapInheritedProperties();     } } As you have seen so far, we used its Requires method to customize TPH. We also used its ToTable method to create a TPT and now we are using its MapInheritedProperties along with ToTable method to create our TPC mapping. TPC Configuration is Not Done Yet!We are not quite done with our TPC configuration and there is more into this story even though the fluent API we saw perfectly created a TPC mapping for us in the database. To see why, let's start working with our object model. For example, the following code creates two new objects of BankAccount and CreditCard types and tries to add them to the database: using (var context = new InheritanceMappingContext()) {     BankAccount bankAccount = new BankAccount();     CreditCard creditCard = new CreditCard() { CardType = 1 };                      context.BillingDetails.Add(bankAccount);     context.BillingDetails.Add(creditCard);     context.SaveChanges(); } Running this code throws an InvalidOperationException with this message: The changes to the database were committed successfully, but an error occurred while updating the object context. The ObjectContext might be in an inconsistent state. Inner exception message: AcceptChanges cannot continue because the object's key values conflict with another object in the ObjectStateManager. Make sure that the key values are unique before calling AcceptChanges. The reason we got this exception is because DbContext.SaveChanges() internally invokes SaveChanges method of its internal ObjectContext. ObjectContext's SaveChanges method on its turn by default calls AcceptAllChanges after it has performed the database modifications. AcceptAllChanges method merely iterates over all entries in ObjectStateManager and invokes AcceptChanges on each of them. Since the entities are in Added state, AcceptChanges method replaces their temporary EntityKey with a regular EntityKey based on the primary key values (i.e. BillingDetailId) that come back from the database and that's where the problem occurs since both the entities have been assigned the same value for their primary key by the database (i.e. on both BillingDetailId = 1) and the problem is that ObjectStateManager cannot track objects of the same type (i.e. BillingDetail) with the same EntityKey value hence it throws. If you take a closer look at the TPC's SQL schema above, you'll see why the database generated the same values for the primary keys: the BillingDetailId column in both BankAccounts and CreditCards table has been marked as identity. How to Solve The Identity Problem in TPC As you saw, using SQL Server’s int identity columns doesn't work very well together with TPC since there will be duplicate entity keys when inserting in subclasses tables with all having the same identity seed. Therefore, to solve this, either a spread seed (where each table has its own initial seed value) will be needed, or a mechanism other than SQL Server’s int identity should be used. Some other RDBMSes have other mechanisms allowing a sequence (identity) to be shared by multiple tables, and something similar can be achieved with GUID keys in SQL Server. While using GUID keys, or int identity keys with different starting seeds will solve the problem but yet another solution would be to completely switch off identity on the primary key property. As a result, we need to take the responsibility of providing unique keys when inserting records to the database. We will go with this solution since it works regardless of which database engine is used. Switching Off Identity in Code First We can switch off identity simply by placing DatabaseGenerated attribute on the primary key property and pass DatabaseGenerationOption.None to its constructor. DatabaseGenerated attribute is a new data annotation which has been added to System.ComponentModel.DataAnnotations namespace in CTP5: public abstract class BillingDetail {     [DatabaseGenerated(DatabaseGenerationOption.None)]     public int BillingDetailId { get; set; }     public string Owner { get; set; }     public string Number { get; set; } } As always, we can achieve the same result by using fluent API, if you prefer that: modelBuilder.Entity<BillingDetail>()             .Property(p => p.BillingDetailId)             .HasDatabaseGenerationOption(DatabaseGenerationOption.None); Working With The Object Model Our TPC mapping is ready and we can try adding new records to the database. But, like I said, now we need to take care of providing unique keys when creating new objects: using (var context = new InheritanceMappingContext()) {     BankAccount bankAccount = new BankAccount()      {          BillingDetailId = 1                          };     CreditCard creditCard = new CreditCard()      {          BillingDetailId = 2,         CardType = 1     };                      context.BillingDetails.Add(bankAccount);     context.BillingDetails.Add(creditCard);     context.SaveChanges(); } Polymorphic Associations with TPC is Problematic The main problem with this approach is that it doesn’t support Polymorphic Associations very well. After all, in the database, associations are represented as foreign key relationships and in TPC, the subclasses are all mapped to different tables so a polymorphic association to their base class (abstract BillingDetail in our example) cannot be represented as a simple foreign key relationship. For example, consider the the domain model we introduced here where User has a polymorphic association with BillingDetail. This would be problematic in our TPC Schema, because if User has a many-to-one relationship with BillingDetail, the Users table would need a single foreign key column, which would have to refer both concrete subclass tables. This isn’t possible with regular foreign key constraints. Schema Evolution with TPC is Complex A further conceptual problem with this mapping strategy is that several different columns, of different tables, share exactly the same semantics. This makes schema evolution more complex. For example, a change to a base class property results in changes to multiple columns. It also makes it much more difficult to implement database integrity constraints that apply to all subclasses. Generated SQLLet's examine SQL output for polymorphic queries in TPC mapping. For example, consider this polymorphic query for all BillingDetails and the resulting SQL statements that being executed in the database: var query = from b in context.BillingDetails select b; Just like the SQL query generated by TPT mapping, the CASE statements that you see in the beginning of the query is merely to ensure columns that are irrelevant for a particular row have NULL values in the returning flattened table. (e.g. BankName for a row that represents a CreditCard type). TPC's SQL Queries are Union Based As you can see in the above screenshot, the first SELECT uses a FROM-clause subquery (which is selected with a red rectangle) to retrieve all instances of BillingDetails from all concrete class tables. The tables are combined with a UNION operator, and a literal (in this case, 0 and 1) is inserted into the intermediate result; (look at the lines highlighted in yellow.) EF reads this to instantiate the correct class given the data from a particular row. A union requires that the queries that are combined, project over the same columns; hence, EF has to pad and fill up nonexistent columns with NULL. This query will really perform well since here we can let the database optimizer find the best execution plan to combine rows from several tables. There is also no Joins involved so it has a better performance than the SQL queries generated by TPT where a Join is required between the base and subclasses tables. Choosing Strategy GuidelinesBefore we get into this discussion, I want to emphasize that there is no one single "best strategy fits all scenarios" exists. As you saw, each of the approaches have their own advantages and drawbacks. Here are some rules of thumb to identify the best strategy in a particular scenario: If you don’t require polymorphic associations or queries, lean toward TPC—in other words, if you never or rarely query for BillingDetails and you have no class that has an association to BillingDetail base class. I recommend TPC (only) for the top level of your class hierarchy, where polymorphism isn’t usually required, and when modification of the base class in the future is unlikely. If you do require polymorphic associations or queries, and subclasses declare relatively few properties (particularly if the main difference between subclasses is in their behavior), lean toward TPH. Your goal is to minimize the number of nullable columns and to convince yourself (and your DBA) that a denormalized schema won’t create problems in the long run. If you do require polymorphic associations or queries, and subclasses declare many properties (subclasses differ mainly by the data they hold), lean toward TPT. Or, depending on the width and depth of your inheritance hierarchy and the possible cost of joins versus unions, use TPC. By default, choose TPH only for simple problems. For more complex cases (or when you’re overruled by a data modeler insisting on the importance of nullability constraints and normalization), you should consider the TPT strategy. But at that point, ask yourself whether it may not be better to remodel inheritance as delegation in the object model (delegation is a way of making composition as powerful for reuse as inheritance). Complex inheritance is often best avoided for all sorts of reasons unrelated to persistence or ORM. EF acts as a buffer between the domain and relational models, but that doesn’t mean you can ignore persistence concerns when designing your classes. SummaryIn this series, we focused on one of the main structural aspect of the object/relational paradigm mismatch which is inheritance and discussed how EF solve this problem as an ORM solution. We learned about the three well-known inheritance mapping strategies and their implementations in EF Code First. Hopefully it gives you a better insight about the mapping of inheritance hierarchies as well as choosing the best strategy for your particular scenario. Happy New Year and Happy Code-Firsting! References ADO.NET team blog Java Persistence with Hibernate book a { color: #5A99FF; } a:visited { color: #5A99FF; } .title { padding-bottom: 5px; font-family: Segoe UI; font-size: 11pt; font-weight: bold; padding-top: 15px; } .code, .typeName { font-family: consolas; } .typeName { color: #2b91af; } .padTop5 { padding-top: 5px; } .padTop10 { padding-top: 10px; } .exception { background-color: #f0f0f0; font-style: italic; padding-bottom: 5px; padding-left: 5px; padding-top: 5px; padding-right: 5px; }

    Read the article

  • LLBLGen Pro feature highlights: automatic element name construction

    - by FransBouma
    (This post is part of a series of posts about features of the LLBLGen Pro system) One of the things one might take for granted but which has a huge impact on the time spent in an entity modeling environment is the way the system creates names for elements out of the information provided, in short: automatic element name construction. Element names are created in both directions of modeling: database first and model first and the more names the system can create for you without you having to rename them, the better. LLBLGen Pro has a rich, fine grained system for creating element names out of the meta-data available, which I'll describe more in detail below. First the model element related element naming features are highlighted, in the section Automatic model element naming features and after that I'll go more into detail about the relational model element naming features LLBLGen Pro has to offer in the section Automatic relational model element naming features. Automatic model element naming features When working database first, the element names in the model, e.g. entity names, entity field names and so on, are in general determined from the relational model element (e.g. table, table field) they're mapped on, as the model elements are reverse engineered from these relational model elements. It doesn't take rocket science to automatically name an entity Customer if the entity was created after reverse engineering a table named Customer. It gets a little trickier when the entity which was created by reverse engineering a table called TBL_ORDER_LINES has to be named 'OrderLine' automatically. Automatic model element naming also takes into effect with model first development, where some settings are used to provide you with a default name, e.g. in the case of navigator name creation when you create a new relationship. The features below are available to you in the Project Settings. Open Project Settings on a loaded project and navigate to Conventions -> Element Name Construction. Strippers! The above example 'TBL_ORDER_LINES' shows that some parts of the table name might not be needed for name creation, in this case the 'TBL_' prefix. Some 'brilliant' DBAs even add suffixes to table names, fragments you might not want to appear in the entity names. LLBLGen Pro offers you to define both prefix and suffix fragments to strip off of table, view, stored procedure, parameter, table field and view field names. In the example above, the fragment 'TBL_' is a good candidate for such a strip pattern. You can specify more than one pattern for e.g. the table prefix strip pattern, so even a really messy schema can still be used to produce clean names. Underscores Be Gone Another thing you might get rid of are underscores. After all, most naming schemes for entities and their classes use PasCal casing rules and don't allow for underscores to appear. LLBLGen Pro can automatically strip out underscores for you. It's an optional feature, so if you like the underscores, you're not forced to see them go: LLBLGen Pro will leave them alone when ordered to to so. PasCal everywhere... or not, your call LLBLGen Pro can automatically PasCal case names on word breaks. It determines word breaks in a couple of ways: a space marks a word break, an underscore marks a word break and a case difference marks a word break. It will remove spaces in all cases, and based on the underscore removal setting, keep or remove the underscores, and upper-case the first character of a word break fragment, and lower case the rest. Say, we keep the defaults, which is remove underscores and PasCal case always and strip the TBL_ fragment, we get with our example TBL_ORDER_LINES, after stripping TBL_ from the table name two word fragments: ORDER and LINES. The underscores are removed, the first character of each fragment is upper-cased, the rest lower-cased, so this results in OrderLines. Almost there! Pluralization and Singularization In general entity names are singular, like Customer or OrderLine so LLBLGen Pro offers a way to singularize the names. This will convert OrderLines, the result we got after the PasCal casing functionality, into OrderLine, exactly what we're after. Show me the patterns! There are other situations in which you want more flexibility. Say, you have an entity Customer and an entity Order and there's a foreign key constraint defined from the target of Order and the target of Customer. This foreign key constraint results in a 1:n relationship between the entities Customer and Order. A relationship has navigators mapped onto the relationship in both entities the relationship is between. For this particular relationship we'd like to have Customer as navigator in Order and Orders as navigator in Customer, so the relationship becomes Customer.Orders 1:n Order.Customer. To control the naming of these navigators for the various relationship types, LLBLGen Pro defines a set of patterns which allow you, using macros, to define how the auto-created navigator names will look like. For example, if you rather have Customer.OrderCollection, you can do so, by changing the pattern from {$EndEntityName$P} to {$EndEntityName}Collection. The $P directive makes sure the name is pluralized, which is not what you want if you're going for <EntityName>Collection, hence it's removed. When working model first, it's a given you'll create foreign key fields along the way when you define relationships. For example, you've defined two entities: Customer and Order, and they have their fields setup properly. Now you want to define a relationship between them. This will automatically create a foreign key field in the Order entity, which reflects the value of the PK field in Customer. (No worries if you hate the foreign key fields in your classes, on NHibernate and EF these can be hidden in the generated code if you want to). A specific pattern is available for you to direct LLBLGen Pro how to name this foreign key field. For example, if all your entities have Id as PK field, you might want to have a different name than Id as foreign key field. In our Customer - Order example, you might want to have CustomerId instead as foreign key name in Order. The pattern for foreign key fields gives you that freedom. Abbreviations... make sense of OrdNr and friends I already described word breaks in the PasCal casing paragraph, how they're used for the PasCal casing in the constructed name. Word breaks are used for another neat feature LLBLGen Pro has to offer: abbreviation support. Burt, your friendly DBA in the dungeons below the office has a hate-hate relationship with his keyboard: he can't stand it: typing is something he avoids like the plague. This has resulted in tables and fields which have names which are very short, but also very unreadable. Example: our TBL_ORDER_LINES example has a lovely field called ORD_NR. What you would like to see in your fancy new OrderLine entity mapped onto this table is a field called OrderNumber, not a field called OrdNr. What you also like is to not have to rename that field manually. There are better things to do with your time, after all. LLBLGen Pro has you covered. All it takes is to define some abbreviation - full word pairs and during reverse engineering model elements from tables/views, LLBLGen Pro will take care of the rest. For the ORD_NR field, you need two values: ORD as abbreviation and Order as full word, and NR as abbreviation and Number as full word. LLBLGen Pro will now convert every word fragment found with the word breaks which matches an abbreviation to the given full word. They're case sensitive and can be found in the Project Settings: Navigate to Conventions -> Element Name Construction -> Abbreviations. Automatic relational model element naming features Not everyone works database first: it may very well be the case you start from scratch, or have to add additional tables to an existing database. For these situations, it's key you have the flexibility that you can control the created table names and table fields without any work: let the designer create these names based on the entity model you defined and a set of rules. LLBLGen Pro offers several features in this area, which are described in more detail below. These features are found in Project Settings: navigate to Conventions -> Model First Development. Underscores, welcome back! Not every database is case insensitive, and not every organization requires PasCal cased table/field names, some demand all lower or all uppercase names with underscores at word breaks. Say you create an entity model with an entity called OrderLine. You work with Oracle and your organization requires underscores at word breaks: a table created from OrderLine should be called ORDER_LINE. LLBLGen Pro allows you to do that: with a simple checkbox you can order LLBLGen Pro to insert an underscore at each word break for the type of database you're working with: case sensitive or case insensitive. Checking the checkbox Insert underscore at word break case insensitive dbs will let LLBLGen Pro create a table from the entity called Order_Line. Half-way there, as there are still lower case characters there and you need all caps. No worries, see below Casing directives so everyone can sleep well at night For case sensitive databases and case insensitive databases there is one setting for each of them which controls the casing of the name created from a model element (e.g. a table created from an entity definition using the auto-mapping feature). The settings can have the following values: AsProjectElement, AllUpperCase or AllLowerCase. AsProjectElement is the default, and it keeps the casing as-is. In our example, we need to get all upper case characters, so we select AllUpperCase for the setting for case sensitive databases. This will produce the name ORDER_LINE. Sequence naming after a pattern Some databases support sequences, and using model-first development it's key to have sequences, when needed, to be created automatically and if possible using a name which shows where they're used. Say you have an entity Order and you want to have the PK values be created by the database using a sequence. The database you're using supports sequences (e.g. Oracle) and as you want all numeric PK fields to be sequenced, you have enabled this by the setting Auto assign sequences to integer pks. When you're using LLBLGen Pro's auto-map feature, to create new tables and constraints from the model, it will create a new table, ORDER, based on your settings I previously discussed above, with a PK field ID and it also creates a sequence, SEQ_ORDER, which is auto-assigns to the ID field mapping. The name of the sequence is created by using a pattern, defined in the Model First Development setting Sequence pattern, which uses plain text and macros like with the other patterns previously discussed. Grouping and schemas When you start from scratch, and you're working model first, the tables created by LLBLGen Pro will be in a catalog and / or schema created by LLBLGen Pro as well. If you use LLBLGen Pro's grouping feature, which allows you to group entities and other model elements into groups in the project (described in a future blog post), you might want to have that group name reflected in the schema name the targets of the model elements are in. Say you have a model with a group CRM and a group HRM, both with entities unique for these groups, e.g. Employee in HRM, Customer in CRM. When auto-mapping this model to create tables, you might want to have the table created for Employee in the HRM schema but the table created for Customer in the CRM schema. LLBLGen Pro will do just that when you check the setting Set schema name after group name to true (default). This gives you total control over where what is placed in the database from your model. But I want plural table names... and TBL_ prefixes! For now we follow best practices which suggest singular table names and no prefixes/suffixes for names. Of course that won't keep everyone happy, so we're looking into making it possible to have that in a future version. Conclusion LLBLGen Pro offers a variety of options to let the modeling system do as much work for you as possible. Hopefully you enjoyed this little highlight post and that it has given you new insights in the smaller features available to you in LLBLGen Pro, ones you might not have thought off in the first place. Enjoy!

    Read the article

  • Hibernate error: cannot resolve table

    - by Roman
    I'm trying to make work the example from hibernate reference. I've got simple table Pupil with id, name and age fields. I've created correct (as I think) java-class for it according to all java-beans rules. I've created configuration file - hibernate.cfg.xml, just like in the example from reference. I've created hibernate mapping for one class Pupil, and here is the error occured. <hibernate-mapping> <class name="Pupil" table="pupils"> ... </class> </hibernate-mapping> table="pupils" is red in my IDE and I see message "cannot resolve table pupils". I've also founded very strange note in reference which says that most users fail with the same problem trying to run the example. Ah.. I'm very angry with this example.. IMHO if authors know that there is such problem they should add some information about it. But, how should I fix it? I don't want to deal with Ant here and with other instruments used in example. I'm using MySql 5.0, but I think it doesn't matter. UPD: source code Pupil.java - my persistent class package domain; public class Pupil { private Integer id; private String name; private Integer age; protected Pupil () { } public Pupil (String name, int age) { this.age = age; this.name = name; } public Integer getId () { return id; } public void setId (Integer id) { this.id = id; } public String getName () { return name; } public void setName (String name) { this.name = name; } public Integer getAge () { return age; } public void setAge (Integer age) { this.age = age; } public String toString () { return "Pupil [ name = " + name + ", age = " + age + " ]"; } } Pupil.hbm.xml is mapping for this class <?xml version="1.0"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> <hibernate-mapping package="domain" > <class name="Pupil" table="pupils"> <id name="id"> <generator class="native" /> </id> <property name="name" not-null="true"/> <property name="age"/> </class> </hibernate-mapping> hibernate.cfg.xml - configuration for hibernate <hibernate-configuration> <session-factory> <!-- Database connection settings --> <property name="connection.driver_class">com.mysql.jdbc.Driver</property> <property name="connection.url">jdbc:mysql://localhost/hbm_test</property> <property name="connection.username">root</property> <property name="connection.password">root</property> <property name="connection.pool_size">1</property> <property name="dialect">org.hibernate.dialect.MySQL5Dialect</property> <property name="current_session_context_class">thread</property> <property name="show_sql">true</property> <mapping resource="domain/Pupil.hbm.xml"/> </session-factory> </hibernate-configuration> HibernateUtils.java package utils; import org.hibernate.SessionFactory; import org.hibernate.HibernateException; import org.hibernate.cfg.Configuration; public class HibernateUtils { private static final SessionFactory sessionFactory; static { try { sessionFactory = new Configuration ().configure ().buildSessionFactory (); } catch (HibernateException he) { System.err.println (he); throw new ExceptionInInitializerError (he); } } public static SessionFactory getSessionFactory () { return sessionFactory; } } Runner.java - class for testing hibernate import org.hibernate.Session; import java.util.*; import utils.HibernateUtils; import domain.Pupil; public class Runner { public static void main (String[] args) { Session s = HibernateUtils.getSessionFactory ().getCurrentSession (); s.beginTransaction (); List pups = s.createQuery ("from Pupil").list (); for (Object obj : pups) { System.out.println (obj); } s.getTransaction ().commit (); HibernateUtils.getSessionFactory ().close (); } } My libs: antlr-2.7.6.jar, asm.jar, asm-attrs.jar, cglib-2.1.3.jar, commons-collections-2.1.1.jar, commons-logging-1.0.4.jar, dom4j-1.6.1.jar, hibernate3.jar, jta.jar, log4j-1.2.11.jar, mysql-connector-java-5.1.7-bin.jar Compile error: cannot resolve table pupils

    Read the article

  • What does setting the GL color before doing a texture mapping operation do?

    - by quixoto
    I am looking at some sample code in a book that creates a jittered antialiasing effect by repeatedly rendering a scene (at different offsets) onto a offscreen texture, then using that texture to repeatedly draw a quad in the main view with some blend stuff set up. To accumulate the color "correctly", the code is setting the color like so: glColor4f(f, f, f, 1); where f is 1.0/number_of_samples, and then binding the offscreen texture and rendering it. Since textures come with their own color and alpha data, what is the effect (mathematically and intuitively) that setting the overall "color" in advance achieves? Thanks.

    Read the article

  • Question about [literally] mapping location based on an IP address.

    - by Andrew
    I've been bored lately and I want to start a new project. I was looking at a website mentioned in a different question (http://www.grapevinegame.com/), and I thought the map and how it plots a point based on someone's IP (I assume) is pretty nifty. I want to do something like that, but I have no idea how it's done. I know you can get latitude and longitude, city and state, and some more with some already-written scripts, but how would you plot those on a map of the world? I've seen it other places, like Google Analytics and such, as well. It seems like a neat thing to be able to do, so I was just wondering how exactly it works. :-p.

    Read the article

  • Determine arc-length of a Catmull-Rom spline

    - by Wouter
    I have a path that is defined by a concatenation of Catmull-Rom splines. I use the static method Vector2.CatmullRom in XNA that allows for interpolation between points with a value going from 0 to 1. Not every spline in this path has the same length. This causes speed differences if I let the weight go at a constant speed for every spline while proceeding along the path. I can remedy this by letting the speed of the weight be dependent on the length of the spline. How can I determine the length of such a spline? Should I just approximate by cutting the spline into 10 straight lines and sum their lengths? I'm using this for dynamic texture mapping on a generated mesh defined by splines.

    Read the article

  • Texturize a shape of multiple triangles in 2D

    - by Deukalion
    This is an example of a shape consisting of multiple points, triangles and eventually a shape: Red Dots = Vector3 (X, Y, Z) or Vector2 (X, Y) If I have a Texture of a certain size, how do I texturize this area in the best way so that the texture inside the shape matches the shape and does not overlap anywhere? Perhaps also with a chance to scale the texture in case it's too small or to big for the shape, but still so that it gets rendered correctly. Do I treat the shape as a rectangle? Figure out it's 4 corners? Or do I calculate the distance between Center - (Texture Width / 2) and Point (to see how "many" times the texture can fit between on that axis to estimate at what Coordinates the Texture should be at that certain point? I've looked at Texture Mapping but haven't found any concrete examples that it explains it well, it's also confusing with 0.0-1.0 values for Texture Coordinates.

    Read the article

  • Shadowmap first phase and shaders

    - by KaiserJohaan
    I am using OpenGL 3.3 and am tryin to implement shadow mapping using cube maps. I have a framebuffer with a depth attachment and a cube map texture. My question is how to design the shaders for the first pass, when creating the shadowmap. This is my vertex shader: in vec3 position; uniform mat4 lightWVP; void main() { gl_Position = lightWVP * vec4(position, 1.0); } Now, do I even need a fragment shader in this shader pass? from what I understand after reading http://www.opengl.org/wiki/Fragment_Shader, by default gl_FragCoord.z is written to the currently attached depth component (to which my cubemap texture is bound to). Thus I shouldnt even need a fragment shader for this pass and from what I understand, there is no other work to do in the fragment shader other than writing this value. Is this correct?

    Read the article

  • Point Light Soft Shadows

    - by notabene
    How to implement soft shadows for omni directional (point) light. We use typical shadow mapping technique. Depth is rendered to texture cube and addresing is pretty simple then. Just using vector from light to fragments world position. It works perfectly. Until you want soft shadows. In our engine we use PCSS technique for spot lights. But for point light there begins troubles. How to sample in 3D? I developed technique when orthonormal basis is created from a direction and upvector (0,1,0). And then multiply sampling vector (something like this (1.0,i/depthMapSize,j/depthMapSize) with this basis. But this (of course :)) looks pretty bad for vectors near (0,1,0) and (0,-1,0). I will appreciate any help on this.

    Read the article

  • What are some ways to texture map a terrain?

    - by ApocKalipsS
    I'm working with XNA on a 3D Game, and I'm trying to have a proper and nice environnement. I actually followed a tutorial to create a terrain from a heightmap. To texture it, I just apply a grass texture on it and tile it a number of times. But what I want to do is to have a really realistic texturing, but also generate it automatically (for example if I want to use Perlin noise to generate a terrain and then texture it). I already learned about multi-texturing, loading a map file with different colors for different textures, but I don't think this is really efficient, for instance for cliffs or very steep areas it will tile a texture badly as it's a view from the top. (Also, I don't know how I'll draw roads or dirt paths with that.) I'm looking for an efficient solution to realistically texture mapping procedurally-generated terrain.

    Read the article

  • Depth Map resolution shifting

    - by user3669538
    the problem is with shadow mapping as you can see, actually it works fine but in a certain condition that the Depth Map size must be equal to the size of rendering buffer, I use an infinite directional light so if the window is 800x600 the depth map must be 800x600, and when i change the size of the shadow map to be 900x600 it starts to be shifted and when it's size be 1024x1024 it also shifts till it disappears the GLSL shadow function float calcShadow(sampler2D Dmap, vec4 coor){ vec4 sh = vec4((coor.xyz/coor.w),1); sh.z *= 0.9; return step(sh.z,texture2D(Dmap,sh.xy).r); } here's the result when it's the same size as the window Colored result & Depth Map and here's the shifted result, as you can notice the depth map is exactly as the previous one with the addition of white space to the right. Colored result http://goo.gl/5lYIFV Depth Map http://goo.gl/7320Dd

    Read the article

  • web.xml : URL mapping

    - by Devashish Dixit
    I have these two lines in my web.xml <url-pattern>/</url-pattern> : Index Servletand <url-pattern>/login</url-pattern> : Login Servlet but whem I open http://localhost:8084/login/, it goes to Index Servlet and when I open http://localhost:8084/login, it goes to Login Servlet. Is there any difference in http://localhost:8084/login/ and http://localhost:8084/login? My web.xml <servlet> <servlet-name>Index</servlet-name> <servlet-class>Index</servlet-class> </servlet> <servlet> <servlet-name>Login</servlet-name> <servlet-class>Login</servlet-class> </servlet> and <servlet-mapping> <servlet-name>Index</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>Login</servlet-name> <url-pattern>/login</url-pattern> </servlet-mapping>

    Read the article

  • unable to ping hostname, but \\hostname\\c$ works!?

    - by ciscokid
    I'm having a strange issue on my initial lab setup. Situation: Host with OS Server 2008 R2 64bit, on this host a Virtual Machine in Hyper-V with OS Server 2008 SP1 32bit. The virtual machine has a fixed ip, and is referring to itself for the preferred DNS Server (dns server role has been installed). The host has tcp/ip set to automatic (so automatic ip from router, and dns/gateway = router). Both are able to ping each other on IP address (same ip range). Both are NOT able to ping each other on hostname (sounds logic because virtual machine dns server does not yet have a dns record for the hostmachine). But here's the strange thing: I am able to set up a working network mapping on the Virtual Machine to the host: \hostname\c$. The first thing I thougt was 'something' is blocking the ping request, so I completely disabled Windows Firewall on both Virtual Machine and host. Still pinging on hostname in both ways didn't work, yet I am able to access the network mapping on hostname. There is no extra software installed on both systems (clean windows server 2008).Can someone tell me what is causing this? I always thought: ping on IP address works = network mapping on IP address works. Pinging on hostname doesn't work = network mapping on hostname doesn't work neither. Where am I wrong? Looking forward to your advice!

    Read the article

  • LLBLGen Pro v3.0 with Entity Framework v4.0 (12m video)

    - by FransBouma
    Today I recorded a video in which I illustrate some of the database-first functionality available in LLBLGen Pro v3.0. LLBLGen Pro v3.0 also supports model-first functionality, which I hope to illustrate in an upcoming video. LLBLGen Pro v3.0 is currently in beta and is scheduled to RTM some time in May 2010. It supports the following frameworks out of the box, with more scheduled to follow in the coming year: LLBLGen Pro RTL (our own o/r mapper framework), Linq to Sql, NHibernate and Entity Framework (v1 and v4). The video I linked to below illustrates the creation of an entity model for Entity Framework v4, by reverse engineering the SQL Server 2008 example database 'AdventureWorks'. The following topics (among others) are included in the video: Abbreviation support (example: convert 'Qty' into 'Quantity' during name construction) Flexible, framework specific settings Attribute definitions for various elements (so no requirement for buddy-classes or messing with generated code or templates) Retrieval of relational model data from a database Reverse engineering of tables into entities, automatically placed in groups Auto-creation of inheritance hierarchies Refactoring of entity fields into Value Type Definitions (DDD) Mapping a Typed view onto a stored procedure resultset Creation of a Typed list (definition of a query with a projection) on a set of related entities Validation and correction of found inconsistencies and errors Generating code using one of the pre-defined presets Illustration of the code in vs.net 2010 It also gives a good overview of what it takes with LLBLGen Pro v3.0 to start from a new project, point it to a database, get an entity model, perform tweaks and validation and generate code which is ready to run. I am no video recording expert so there's no audio and some mouse movements might be a little too quickly. If that's the case, please pause the video. It's rather big (52MB). Click here to open the HTML page with the video (Flash). Opens in a new window. LLBLGen Pro v3.0 is currently in beta (available for v2.x customers) and scheduled to be released somewhere in May 2010.

    Read the article

  • LLBLGen Pro v3.0 has been released!

    - by FransBouma
    After two years of hard work we released v3.0 of LLBLGen Pro today! V3.0 comes with a completely new designer which has been developed from the ground up for .NET 3.5 and higher. Below I'll briefly mention some highlights of this new release: Entity Framework (v1 & v4) support NHibernate support (hbm.xml mappings & FluentNHibernate mappings) Linq to SQL support Allows both Model first and Database first development, or a mixture of both .NET 4.0 support Model views Grouping of project elements Linq-based project search Value Type (DDD) support Multiple Database types in single project XML based project file Integrated template editor Relational Model Data management Flexible attribute declaration for code generation, no more buddy classes needed Fine-grained project validation Update / Create DDL SQL scripts Fast Text-DSL based Quick mode Powerful text-DSL based Quick Model functionality Per target framework extensible settings framework much much more... Of course we still support our own O/R mapper framework: LLBLGen Pro v3.0 Runtime framework as well, which was updated with some minor features and was upgraded to use the DbProviderFactory system. Please watch the videos of the designer (more to come very soon!) to see some aspects of the new designer in action. The full version comes with Algorithmia in sourcecode as well. Algorithmia is an algorithm library written for .NET 3.5 which powers the heart of the designer with a fine-grained undo/redo command framework, graph classes and much more. I'd like to thank all beta-testers, our support team and others who have helped us with this massive release. :)

    Read the article

  • LLBLGen Pro v3.1 released!

    - by FransBouma
    Yesterday we released LLBLGen Pro v3.1! Version 3.1 comes with new features and enhancements, which I'll describe briefly below. v3.1 is a free upgrade for v3.x licensees. What's new / changed? Designer Extensible Import system. An extensible import system has been added to the designer to import project data from external sources. Importers are plug-ins which import project meta-data (like entity definitions, mappings and relational model data) from an external source into the loaded project. In v3.1, an importer plug-in for importing project elements from existing LLBLGen Pro v3.x project files has been included. You can use this importer to create source projects from which you import parts of models to build your actual project with. Model-only relationships. In v3.1, relationships of the type 1:1, m:1 and 1:n can be marked as model-only. A model-only relationship isn't required to have a backing foreign key constraint in the relational model data. They're ideal for projects which have to work with relational databases where changes can't always be made or some relationships can't be added to (e.g. the ones which are important for the entity model, but are not allowed to be added to the relational model for some reason). Custom field ordering. Although fields in an entity definition don't really have an ordering, it can be important for some situations to have the entity fields in a given order, e.g. when you use compound primary keys. Field ordering can be defined using a pop-up dialog which can be opened through various ways, e.g. inside the project explorer, model view and entity editor. It can also be set automatically during refreshes based on new settings. Command line relational model data refresher tool, CliRefresher.exe. The command line refresh tool shipped with v2.6 is now available for v3.1 as well Navigation enhancements in various designer elements. It's now easier to find elements like entities, typed views etc. in the project explorer from editors, to navigate to related entities in the project explorer by right clicking a relationship, navigate to the super-type in the project explorer when right-clicking an entity and navigate to the sub-type in the project explorer when right-clicking a sub-type node in the project explorer. Minor visual enhancements / tweaks LLBLGen Pro Runtime Framework Entity creation is now up to 30% faster and takes 5% less memory. Creating an entity object has been optimized further by tweaks inside the framework to make instantiating an entity object up to 30% faster. It now also takes up to 5% less memory than in v3.0 Prefetch Path node merging is now up to 20-25% faster. Setting entity references required the creation of a new relationship object. As this relationship object is always used internally it could be cached (as it's used for syncing only). This increases performance by 20-25% in the merging functionality. Entity fetches are now up to 20% faster. A large number of tweaks have been applied to make entity fetches up to 20% faster than in v3.0. Full WCF RIA support. It's now possible to use your LLBLGen Pro runtime framework powered domain layer in a WCF RIA application using the VS.NET tools for WCF RIA services. WCF RIA services is a Microsoft technology for .NET 4 and typically used within silverlight applications. SQL Server DQE compatibility level is now per instance. (Usable in Adapter). It's now possible to set the compatibility level of the SQL Server Dynamic Query Engine (DQE) per instance of the DQE instead of the global setting it was before. The global setting is still available and is used as the default value for the compatibility level per-instance. You can use this to switch between CE Desktop and normal SQL Server compatibility per DataAccessAdapter instance. Support for COUNT_BIG aggregate function (SQL Server specific). The aggregate function COUNT_BIG has been added to the list of available aggregate functions to be used in the framework. Minor changes / tweaks I'm especially pleased with the import system, as that makes working with entity models a lot easier. The import system lets you import from another LLBLGen Pro v3 project any entity definition, mapping and / or meta-data like table definitions. This way you can build repository projects where you store model fragments, e.g. the building blocks for a customer-order system, a user credential model etc., any model you can think of. In most projects, you'll recognize that some parts of your new model look familiar. In these cases it would have been easier if you would have been able to import these parts from projects you had pre-created. With LLBLGen Pro v3.1 you can. For example, say you have an Oracle schema called CRM which contains the bread 'n' butter customer-order-product kind of model. You create an entity model from that schema and save it in a project file. Now you start working on another project for another customer and you have to use SQL Server. You also start using model-first development, so develop the entity model from scratch as there's no existing database. As this customer also requires some CRM like entity model, you import the entities from your saved Oracle project into this new SQL Server targeting project. Because you don't work with Oracle this time, you don't import the relational meta-data, just the entities, their relationships and possibly their inheritance hierarchies, if any. As they're now entities in your project you can change them a bit to match the new customer's requirements. This can save you a lot of time, because you can re-use pre-fab model fragments for new projects. In the example above there are no tables yet (as you work model first) so using the forward mapping capabilities of LLBLGen Pro v3 creates the tables, PK constraints, Unique Constraints and FK constraints for you. This way you can build a nice repository of model fragments which you can re-use in new projects.

    Read the article

  • Hibernate mapping one-to-many problem

    - by Xorty
    Hello, I am not very experienced with Hibernate and I am trying to create one-to-many mapping. Here are relevant tables: And here are my mapping files: <hibernate-mapping package="com.xorty.mailclient.server.domain"> <class name="Attachment" table="Attachment"> <id name="id"> <column name="idAttachment"></column> </id> <property name="filename"> <column name="name"></column> </property> <property name="blob"> <column name="file"></column> <type name="blob"></type> </property> <property name="mailId"> <column name="mail_idmail"></column> </property> </class> </hibernate-mapping> <hibernate-mapping> <class name="com.xorty.mailclient.server.domain.Mail" table="mail"> <id name="id" type="integer" column="idmail"></id> <property name="content"> <column name="body"></column> </property> <property name="ownerAddress"> <column name="account_address"></column> </property> <property name="title"> <column name="head"></column> </property> <set name="receivers" table="mail_has_contact" cascade="all"> <key column="mail_idmail"></key> <many-to-many column="contact_address" class="com.xorty.mailclient.client.domain.Contact"></many-to-many> </set> <list name="attachments" cascade="save-update, delete" inverse="true"> <key column="mail_idmail" not-null="true"/> <index column="fk_Attachment_mail1"></index> <one-to-many class="com.xorty.mailclient.server.domain.Attachment"/> </list> </class> </hibernate-mapping> In plain english, one mail has more attachments. When I try to do CRUD on mail without attachments, everyting works just fine. When I add some attachment to mail, I cannot perform any CRUD operation. I end up with following trace: org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:96) at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66) at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:275) at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:268) at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:184) at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:321) at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:51) at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1216) at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:383) at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:133) at domain.DatabaseTest.testPersistMailWithAttachment(DatabaseTest.java:355) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at junit.framework.TestCase.runTest(TestCase.java:168) at junit.framework.TestCase.runBare(TestCase.java:134) at junit.framework.TestResult$1.protect(TestResult.java:110) at junit.framework.TestResult.runProtected(TestResult.java:128) at junit.framework.TestResult.run(TestResult.java:113) at junit.framework.TestCase.run(TestCase.java:124) at junit.framework.TestSuite.runTest(TestSuite.java:232) at junit.framework.TestSuite.run(TestSuite.java:227) at org.junit.internal.runners.JUnit38ClassRunner.run(JUnit38ClassRunner.java:83) at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:49) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197) Caused by: java.sql.BatchUpdateException: Cannot add or update a child row: a foreign key constraint fails (`maildb`.`attachment`, CONSTRAINT `fk_Attachment_mail1` FOREIGN KEY (`mail_idmail`) REFERENCES `mail` (`idmail`) ON DELETE NO ACTION ON UPDATE NO ACTION) at com.mysql.jdbc.PreparedStatement.executeBatchSerially(PreparedStatement.java:1666) at com.mysql.jdbc.PreparedStatement.executeBatch(PreparedStatement.java:1082) at org.hibernate.jdbc.BatchingBatcher.doExecuteBatch(BatchingBatcher.java:70) at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:268) ... 27 more Thank you

    Read the article

  • Dispatcher for Filter Mapping

    - by George
    I have an app written for Servlet Spec 2.4 with an old webserver designed for Servlet Spec 2.3. The web.xml file has the following syntax: <filter-mapping> <filter-name>sitemesh</filter-name> <url-pattern>*.action</url-pattern> <dispatcher>REQUEST</dispatcher> <dispatcher>FORWARD</dispatcher> </filter-mapping> How can I re-write this mapping to be servlet 2.3 compliant?

    Read the article

  • Multipart question: Mapping between xml and Json using xpath

    - by scope-creep
    This is a JSON mapping question from a json newbie. Currently i'm reading xml using xpath in C#, and the xpath are returning either the element or attribute node values, as is the schema's want. I want to write out some of the returned values into a json formatted file. I know i can faneigle the xpath expression to return the element or attribute names, so I can built the appropriate name/value json structure before serialization, but I was I'm wondering if their was some way of doing a mapping between the xml and json. The xml schema is fairly big, so potentially the mapping will be big, meaning a ton of cumbersom coding to make it work. Is their any way to automap somehow? I was planning to use json.net, which seems flexible enough, although their may be a better approach. Any help would be appreciated. Bob.

    Read the article

  • Vim: different key mapping for different window

    - by rahul
    My .vimrc file has filetype mappings for different filetypes such as : autocmd FileType sh map gf ... autocmd FileType ruby map gf ... While rewriting a program from one language to another, I have 2 splits, one with a shell script and one with ruby. I would assume that "gf" would take on its mapping based on filetype. However, it can only hold one mapping at a time. Is there any way to declare a mapping only for the existing file/window. I tried ":windo" and ":bufdo" but they work for all windows or buffers.

    Read the article

  • styles/style.css No mapping found for HTTP request

    - by sonx
    Hi, it seems my styles folder added under the web folder is not getting mapped by dispatcher servlet on my JSP's. I get WARN : org.springframework.web.servlet.PageNotFound - No mapping found for HTTP request with URI [/onlinebasket/styles/style.css] in DispatcherServlet with name 'onlinebasket' here's my dispatcher servlet <servlet-mapping> <servlet-name>onlinebasket</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> and i this is my CSS URL on JSP <link rel="stylesheet" href="<c:url value="/styles/sytle.css"/>" type="text/css"/> This folder is on the web folder.

    Read the article

  • generating class from hibernate mapping file

    - by Mrityunjay
    hi, i have one mapping file viz. student.hbm.xml.. i need to generate Student.java from the same. the file is below :- <?xml version="1.0" encoding="UTF-8"?> <hibernate-mapping> <class name="org.hibernate.entity.ClassRoom" table="class_room"> <id name="roomId" column="room_id" type="int"/> <property name="roomClass" column="room_class" type="string"/> <property name="floor" column="floor" type="int"/> <property name="roomMaster" column="room_mast" type="string"/> </class> </hibernate-mapping> is there any way i can create the class file from the above file.please help...

    Read the article

  • Servlet mapping for ajax call parameters

    - by Woho87
    Hi guys! <servlet-mapping> <servlet-name>Test</servlet-name> <url-pattern>/GetContacts*</url-pattern> </servlet-mapping> I got a simple problem where I can't find any solution on the internet. I have a ajax calls that have the url http://localhost:80/Push/GetContacts?id=23..... The above servlet mapping is not correct for the AJAX call. it issues a http 404 not found call. What is the right syntax to enable my ajax call?

    Read the article

  • Using Linq to SQL change events with attribute-based mapping

    - by R Mene
    I'm writing a new ASP.NET MVC2 application using Linq to SQL. This application depends on an existing SQL database. I am using attribute-based mapping to map my database fields to my Linq to SQL entities. I also need to make use of Linq to SQL's On[Property]Changed methods so I can perform change-auditing of database tables within my application. Whereas the documentation explains how to do this when using Linq to SQL's ORM and dbml files (i.e. by writing partial classes), it is not clear how to do with when using attribute-based mapping or when using XML-based mapping. It would be very helpful if someone could describe how to do this.

    Read the article

< Previous Page | 48 49 50 51 52 53 54 55 56 57 58 59  | Next Page >