Search Results

Search found 16051 results on 643 pages for 'schema design'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 12/643 | < Previous Page | 8 9 10 11 12 13 14 15 16 17 18 19  | Next Page >

  • Insert into a star-schema

    - by shaun
    I've read a lot about star-schema's, about fact/deminsion tables, select statements to quickly report data, however the matter of data entry into a star-schema seems aloof to me. How does one "theoretically" enter data into a star-schema db? while maintaining the fact table. Is a series of INSERT INTO statement within giant stored proc with 20 params my only option (and how to populate the fact table). Many thanks.

    Read the article

  • XML Schema to restrict one field based on another

    - by Kevin Albrecht
    I have the following schema, which I use to ensure that a person's PhoneNumber and PhoneNumberType (Home, Work, etc.) is not longer than 10 characters. However, I want to improve this schema so that PhoneNumberType is not required if a PhoneNumber is not provided, but is required if the PhoneNumber is provided. Is there a way to do this in XML Schema 1.0? <?xml version="1.0" encoding="UTF-8"?> <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <xs:element name="PhoneNumber"> <xs:simpleType> <xs:restriction base="xs:string"> <xs:minLength value="0"/> <xs:maxLength value="10"/> </xs:restriction> </xs:simpleType> </xs:element> <xs:element name="PhoneNumberType"> <xs:simpleType> <xs:restriction base="xs:string"> <xs:minLength value="0"/> <xs:maxLength value="10"/> </xs:restriction> </xs:simpleType> </xs:element> </xsd:schema>

    Read the article

  • XML validation error when using multiple schema files/namespaces

    - by user129609
    Hi, I've been reading a ton about xml and learning a lot but I am stuck on one error. I have a schema defined in multiple files and I can't get it to work. Here is an example ================================== libraryBooks.xsd <?xml version="1.0" encoding="utf-8"?> <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns="urn:MyNamespace" targetNamespace="urn:MyNamespace" elementFormDefault="qualified" > <xsd:element name="libraryBooks" type="libraryBooksType"/> <xsd:complexType name="libraryBooksType"> <xsd:sequence> <xsd:any minOccurs="0"/> </xsd:sequence> <xsd:attribute name="name" type="xsd:string"/> </xsd:complexType> </xsd:schema> ================================== book.xsd <?xml version="1.0" encoding="utf-8"?> <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns="urn:MyNamespace2" targetNamespace="urn:MyNamespace2" elementFormDefault="qualified" > <xsd:element name="book" type="booksType"/> <xsd:complexType name="bookType"> <xsd:attribute name="title" type="xsd:string"/> </xsd:complexType> </xsd:schema> ================================== myXml.xml <?xml version="1.0" encoding="utf-8" ?> <libraryBooks xmlns="urn:MyNamespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="urn:MyNamespace file:///C:/libraryBooks.xsd" name="CentralLibrary"> <mn2:book xmlns:mn2="file:///C:/book.xsd" title="How to make xml work the way I want"> </mn2:book> </libraryBooks> So the error I get would be "The 'file:///C:/book.xsd:book' element is not found". Any ideas? I'm almost certain it is something simple

    Read the article

  • Book Recommendation: Web Design

    - by injekt
    I'm looking to get back into advanced Web Design. I'd say I was already fairly advanced but I haven't designed much in a good few years and haven't got any books any more. I was just interested to know if anyone had any good recommendations for Web Design books and resources, I've spent the last couple of days looking around but can't make my mind up. Any contributions are greatly appreciated. PS. I have looked around at other questions on StackOverflow that could be related, but couldn't find any that fitted.

    Read the article

  • User Interface design books/resources for programmers

    - by mmacaulay
    Hi, I'm going to make my monthly trip to the bookstore soon and I'm kind of interested in learning some user interface and/or design stuff - mostly web related, what are some good books I should look at? One that I've seen come up frequently in the past is Don't Make Me Think, which looks promising. I'm aware of the fact that programmers often don't make great designers, and as such this is more of a potential hobby thing than a move to be a professional designer. I'm also looking for any good web resources on this topic. I subscribed to Jakob Nielsen's Alertbox newsletter, for instance, although it seems to come only once a month or so. Thanks! Somewhat related questions: http://stackoverflow.com/questions/75863/what-are-the-best-resources-for-designing-user-interfaces http://stackoverflow.com/questions/7973/user-interface-design

    Read the article

  • Schema qualified tables with SQLAlchemy, SQLite and Postgresql?

    - by Chris Reid
    I have a Pylons project and a SQLAlchemy model that implements schema qualified tables: class Hockey(Base): __tablename__ = "hockey" __table_args__ = {'schema':'winter'} hockey_id = sa.Column(sa.types.Integer, sa.Sequence('score_id_seq', optional=True), primary_key=True) baseball_id = sa.Column(sa.types.Integer, sa.ForeignKey('summer.baseball.baseball_id')) This code works great with Postgresql but fails when using SQLite on table and foreign key names (due to SQLite's lack of schema support) sqlalchemy.exc.OperationalError: (OperationalError) unknown database "winter" 'PRAGMA "winter".table_info("hockey")' () I'd like to continue using SQLite for dev and testing. Is there a way of have this fail gracefully on SQLite?

    Read the article

  • DataAdapter Select string from base table schema?

    - by MattSlay
    When I built my .xsd, I had to choose the columns for each table, and it made a schema for the tables, right? So how can I get that Select string to use as a base Select command for new instances of dataadapters, and then just append a Where and OrderBy clause to it as needed? That would keep me from having to keep each DataAdapter's field list (for the same table) in synch with the schema of that table in the .xsd file. Isn't it common to have several DataAdapters that work on a certain table schema, but with different params in the Where and OrderBy clauses? Surely one does not have to maintain (or even redundently build) the field list part of the Select strings for half a dozen DataAdapters that all work off of the same table schema. I'm envisioning something like this pseudo code: BaseSelectString = MyTypedDataSet.JobsTable.GetSelectStringFromSchema() // Is there such a method or technique? WhereClause = " Where SomeField = @Param1 and SomeOtherField = @Param2" OrderByClause = " Order By Field1, Field2" SelectString=BaseSelectString + WhereClause + OrderByClause OleDbDataAdapter adapter = new OleDbDataAdapter(SelectString, MyConn)

    Read the article

  • Validate a XDocument against schema without the ValidationEventHandler (for use in a HTTP handler)

    - by Vaibhav Garg
    Hi everyone, (I am new to Schema validation) Regarding the following method, System.Xml.Schema.Extensions.Validate( ByVal source As System.Xml.Linq.XDocument, ByVal schemas As System.Xml.Schema.XmlSchemaSet, ByVal validationEventHandler As System.Xml.Schema.ValidationEventHandler, ByVal addSchemaInfo As Boolean) I am using it as follows inside a IHttpHandler - Try Dim xsd As XmlReader = XmlReader.Create(context.Server.MapPath("~/App_Data/MySchema.xsd")) Dim schemas As New XmlSchemaSet() : schemas.Add("myNameSpace", xsd) : xsd.Close() myXDoxumentOdj.Validate(schemas, Function(s As Object, e As ValidationEventArgs) SchemaError(s, e, context), True) Catch ex1 As Threading.ThreadAbortException 'manage schema error' Return Catch ex As Exception 'manage other errors' End Try The handler- Function SchemaError(ByVal s As Object, ByVal e As ValidationEventArgs, ByVal c As HttpContext) As Object If c Is Nothing Then c = HttpContext.Current If c IsNot Nothing Then HttpContext.Current.Response.Write(e.Message) HttpContext.Current.Response.End() End If Return New Object() End Function This is working fine for me at present but looks very weak. I do get errors when I feed it bad XML. But i want to implement it in a more elegant way. This looks like it would break for large XML etc. Is there some way to validate without the handler so that I get the document validated in one go and then deal with errors? To me it looks Async such that the call to Validate() would pass and some non deterministic time later the handler would get called with the result/errors. Is that right? Thanks and sorry for any goofy mistakes :).

    Read the article

  • Design Solution For Storing-Fetching Images

    - by Chaitanya
    This is a design doubt am facing, I have a collection of 1500 images which are to be displayed on an asp.net page, the images to be displayed differ from one page to another, the count of these images will increase in the time to come, a.) is it a good idea to have the images on the database, but the round trip time to fetch the images from the database might be high. b.) is it good to have all the images on a directory, and have a virtual file system over it, and the application will access the images from the directory Do we have in particular any design strategy in a traditional database for fetching images with the least round trip time, does any solution other than usage of a traditional database exists? ps: I use SQL Server to store these images.

    Read the article

  • Why does "xsd:date" of XML Schema Type mapped "javax.xml.datatype.XMLGregorianCalendar" When Schema-to-Java Mapping of JAXB does.

    - by Take
    I don't know why does "xsd:date" of XML Schema Type mapped "javax.xml.datatype.XMLGregorianCalendar" When Schema-to-Java Mapping of JAXB does. Why does "xsd:date" of XML Schema Type mapped "java.util.Date" ? I guess that JAXB intentionally does its mapping. I want to know that reason if any. And if exists it, how to change "xsd:date" of XML Schema Type to "java.util.Date" of Java class without using annotation(ex.@XmlJavaTypeAdapter). I want to do mashalling and unmarshalling without all annotations.

    Read the article

  • Creating a 'flexible' XML schema

    - by Fiona Holder
    I need to create a schema for an XML file that is pretty flexible. It has to meet the following requirements: Validate some elements that we require to be present, and know the exact structure of Validate some elements that are optional, and we know the exact structure of Allow any other elements Allow them in any order Quick example: XML <person> <age></age> <lastname></lastname> <height></height> </person> My attempt at an XSD: <xs:schema attributeFormDefault="unqualified" elementFormDefault="qualified" xmlns:xs="http://www.w3.org/2001/XMLSchema"> <xs:element name="person"> <xs:complexType> <xs:sequence> <xs:element name="firstname" minOccurs="0" type="xs:string"/> <xs:element name="lastname" type="xs:string"/> <xs:any processContents="lax" minOccurs="0" maxOccurs="unbounded" /> </xs:sequence> </xs:complexType> </xs:element> </xs:schema> Now my XSD satisfies requirements 1 and 3. It is not a valid schema however, if both firstname and lastname were optional, so it doesn't satisfy requirement 2, and the order is fixed, which fails requirement 4. Now all I need is something to validate my XML. I'm open to suggestions on any way of doing this, either programmatically in .NET 3.5, another type of schema etc. Can anyone think of a solution to satisfy all 4 requirements?

    Read the article

  • Security in Software

    The term security has many meanings based on the context and perspective in which it is used. Security from the perspective of software/system development is the continuous process of maintaining confidentiality, integrity, and availability of a system, sub-system, and system data. This definition at a very high level can be restated as the following: Computer security is a continuous process dealing with confidentiality, integrity, and availability on multiple layers of a system. Key Aspects of Software Security Integrity Confidentiality Availability Integrity within a system is the concept of ensuring only authorized users can only manipulate information through authorized methods and procedures. An example of this can be seen in a simple lead management application.  If the business decided to allow each sales member to only update their own leads in the system and sales managers can update all leads in the system then an integrity violation would occur if a sales member attempted to update someone else’s leads. An integrity violation occurs when a team member attempts to update someone else’s lead because it was not entered by the sales member.  This violates the business rule that leads can only be update by the originating sales member. Confidentiality within a system is the concept of preventing unauthorized access to specific information or tools.  In a perfect world the knowledge of the existence of confidential information/tools would be unknown to all those who do not have access. When this this concept is applied within the context of an application only the authorized information/tools will be available. If we look at the sales lead management system again, leads can only be updated by originating sales members. If we look at this rule then we can say that all sales leads are confidential between the system and the sales person who entered the lead in to the system. The other sales team members would not need to know about the leads let alone need to access it. Availability within a system is the concept of authorized users being able to access the system. A real world example can be seen again from the lead management system. If that system was hosted on a web server then IP restriction can be put in place to limit access to the system based on the requesting IP address. If in this example all of the sales members where accessing the system from the 192.168.1.23 IP address then removing access from all other IPs would be need to ensure that improper access to the system is prevented while approved users can access the system from an authorized location. In essence if the requesting user is not coming from an authorized IP address then the system will appear unavailable to them. This is one way of controlling where a system is accessed. Through the years several design principles have been identified as being beneficial when integrating security aspects into a system. These principles in various combinations allow for a system to achieve the previously defined aspects of security based on generic architectural models. Security Design Principles Least Privilege Fail-Safe Defaults Economy of Mechanism Complete Mediation Open Design Separation Privilege Least Common Mechanism Psychological Acceptability Defense in Depth Least Privilege Design PrincipleThe Least Privilege design principle requires a minimalistic approach to granting user access rights to specific information and tools. Additionally, access rights should be time based as to limit resources access bound to the time needed to complete necessary tasks. The implications of granting access beyond this scope will allow for unnecessary access and the potential for data to be updated out of the approved context. The assigning of access rights will limit system damaging attacks from users whether they are intentional or not. This principle attempts to limit data changes and prevents potential damage from occurring by accident or error by reducing the amount of potential interactions with a resource. Fail-Safe Defaults Design PrincipleThe Fail-Safe Defaults design principle pertains to allowing access to resources based on granted access over access exclusion. This principle is a methodology for allowing resources to be accessed only if explicit access is granted to a user. By default users do not have access to any resources until access has been granted. This approach prevents unauthorized users from gaining access to resource until access is given. Economy of Mechanism Design PrincipleThe Economy of mechanism design principle requires that systems should be designed as simple and small as possible. Design and implementation errors result in unauthorized access to resources that would not be noticed during normal use. Complete Mediation Design PrincipleThe Complete Mediation design principle states that every access to every resource must be validated for authorization. Open Design Design PrincipleThe Open Design Design Principle is a concept that the security of a system and its algorithms should not be dependent on secrecy of its design or implementation Separation Privilege Design PrincipleThe separation privilege design principle requires that all resource approved resource access attempts be granted based on more than a single condition. For example a user should be validated for active status and has access to the specific resource. Least Common Mechanism Design PrincipleThe Least Common Mechanism design principle declares that mechanisms used to access resources should not be shared. Psychological Acceptability Design PrincipleThe Psychological Acceptability design principle refers to security mechanisms not make resources more difficult to access than if the security mechanisms were not present Defense in Depth Design PrincipleThe Defense in Depth design principle is a concept of layering resource access authorization verification in a system reduces the chance of a successful attack. This layered approach to resource authorization requires unauthorized users to circumvent each authorization attempt to gain access to a resource. When designing a system that requires meeting a security quality attribute architects need consider the scope of security needs and the minimum required security qualities. Not every system will need to use all of the basic security design principles but will use one or more in combination based on a company’s and architect’s threshold for system security because the existence of security in an application adds an additional layer to the overall system and can affect performance. That is why the definition of minimum security acceptably is need when a system is design because this quality attributes needs to be factored in with the other system quality attributes so that the system in question adheres to all qualities based on the priorities of the qualities. Resources: Barnum, Sean. Gegick, Michael. (2005). Least Privilege. Retrieved on August 28, 2011 from https://buildsecurityin.us-cert.gov/bsi/articles/knowledge/principles/351-BSI.html Saltzer, Jerry. (2011). BASIC PRINCIPLES OF INFORMATION PROTECTION. Retrieved on August 28, 2011 from  http://web.mit.edu/Saltzer/www/publications/protection/Basic.html Barnum, Sean. Gegick, Michael. (2005). Defense in Depth. Retrieved on August 28, 2011 from  https://buildsecurityin.us-cert.gov/bsi/articles/knowledge/principles/347-BSI.html Bertino, Elisa. (2005). Design Principles for Security. Retrieved on August 28, 2011 from  http://homes.cerias.purdue.edu/~bhargav/cs526/security-9.pdf

    Read the article

  • Suggestions on switching from lamp based web design-development to game design-development

    - by Sandeepan Nath
    I have around 2.5 years of experience as a web developer cum designer working mainly on the LAMP platform. Now, I want to try out game development (of the likes of First Person Shooter games like Call of Duty (COD)). It is one of my dreams to some day succeed in making a profitable, popular, commercial game of this type. However, I have never done any kind of business nor even freelancing yet even in the web domain. Okay, first things first, I am just starting and I don't yet have any idea about the technologies, languages, engines (game engines) etc involved in that. I would like this question to be a complete guide for people with similar interests. Best resources for getting hold really fast What would be the best approach to get the basic hold of the domain really fast? Any resource(s) for programmers coming from other domains/experienced in other domains would be the ideal ones for me. E.g., if anybody would ask me some good resource for quickly learning PHP/Mysql, I would suggest books like "How to do everything with PHP & MySql" - because - it introduces all the basics of the domain (not the advanced things which can be later learnt by practice and also a lot by searching in stackoverflow questions) it contains some very nice working projects in the end, which help in applying the skills learnt in the chapters of the book. This is the best way for self learners, I feel. I would appreciate some similar resource which connects all concepts together to get the bigger picture. I have read about C, C++, C#, JAVA being used in game programming but not sure which language to go for (I have previously learnt a little of C and JAVA). I have also read about game engines but there would be various other concepts. Commonly accepted ways of learning Should 3D games like these be tried after 2D games? Are there some commonly accepted ways of learning such kind of games? Like in web development, we should go for frameworks after practising well with basic language, AJAX after getting properly done with simple page-reload processing etc. Apart from these, any useful tips (like language choices etc.) would be much appreciated. Like it is highly recommended to contribute to open source web projects for getting recognition, are there similar open source game projects? Thanks, Sandeepan

    Read the article

  • BizTalk 2009 - The Community ODBC Adapter: Schema Generation with Input Parameters

    - by Stuart Brierley
    As previsouly noted in my post on Schema Generation using the Community ODBC Adapter, I ran into a problem when trying to generate a schema to represent a MySQL stored procedure that had input parameters.  After a bit of investigation and a few deadends I managed to figure out a way around this issue - detailed below are both the problem and solution in case you ever run into this yourself. The Problem Imagine a stored procedure that is coded as follows in MySQL: StuTest(in DStr varchar(80)) BEGIN   Declare GRNID int;   Select grn_id into GRNID from grn_header where distribution_number = DStr;   Select GRNID; END This is quite a simple stored procedure but can be used to illustrate the issue with parameters quite niceley. When generating the schema using the Add Generated Items wizard, I tried selecting "Stored Procedure" and then in the Statement Information window typing the stored procedure name: StuTest Pressing generate then gives the following error: "Incorrect Number of arguments for Procedure StuTest; expected 1, got 0" If you attempt to supply a value for the parameter you end up with a schema that will only ever supply the parameter value that you specify.  For example supplying StuTest('123') will always call the procedure with a parameter value of 123. The Solution   I tried contacting Two Connect about this, but their experience of testing the adapter with MySQL was limited. After looking through the code for the ODBC adapter myself and trying a few things out, I was eventually able to use the ODBC adapter to call a test stored procedure using a two way send port. In the generate schema wizard instead of selecting Stored Procedure I had to choose SQL Script instead, detailing the following script: Call StuTest(@InputParameter) By default this would create a request schema with an attribute called InputParameter, with a SQL type of NVarChar(1).  In most cases this is not going to be correct for the stored procedure being called. To change the type from the default that is applied you need to select the "Override default query processing" check box when specifying the script in the wizard.  This then opens the BizTalk ODBC Override window which lets you change the properties of the parameters and also test out the query script.  Once I had done this I was then able to generate the correct schema, which included an attribute representing the parameter.  By deploying the schema assembly I was then able to try the ODBC adapter out on a two way send port. When supplied with an appropriate message instance (for the generated request schema) this send port successfully returned the expected response.

    Read the article

  • Developing Schema Compare for Oracle (Part 2): Dependencies

    - by Simon Cooper
    In developing Schema Compare for Oracle, one of the issues we came across was the size of the databases. As detailed in my last blog post, we had to allow schema pre-filtering due to the number of objects in a standard Oracle database. Unfortunately, this leads to some quite tricky situations regarding object dependencies. This post explains how we deal with these dependencies. 1. Cross-schema dependencies Say, in the following database, you're populating SchemaA, and synchronizing SchemaA.Table1: SOURCE   TARGET CREATE TABLE SchemaA.Table1 ( Col1 NUMBER REFERENCES SchemaB.Table1(Col1));   CREATE TABLE SchemaA.Table1 ( Col1 VARCHAR2(100) REFERENCES SchemaB.Table1(Col1)); CREATE TABLE SchemaB.Table1 ( Col1 NUMBER PRIMARY KEY);   CREATE TABLE SchemaB.Table1 ( Col1 VARCHAR2(100) PRIMARY KEY); We need to do a rebuild of SchemaA.Table1 to change Col1 from a VARCHAR2(100) to a NUMBER. This consists of: Creating a table with the new schema Inserting data from the old table to the new table, with appropriate conversion functions (in this case, TO_NUMBER) Dropping the old table Rename new table to same name as old table Unfortunately, in this situation, the rebuild will fail at step 1, as we're trying to create a NUMBER column with a foreign key reference to a VARCHAR2(100) column. As we're only populating SchemaA, the naive implementation of the object population prefiltering (sticking a WHERE owner = 'SCHEMAA' on all the data dictionary queries) will generate an incorrect sync script. What we actually have to do is: Drop foreign key constraint on SchemaA.Table1 Rebuild SchemaB.Table1 Rebuild SchemaA.Table1, adding the foreign key constraint to the new table This means that in order to generate a correct synchronization script for SchemaA.Table1 we have to know what SchemaB.Table1 is, and that it also needs to be rebuilt to successfully rebuild SchemaA.Table1. SchemaB isn't the schema that the user wants to synchronize, but we still have to load the table and column information for SchemaB.Table1 the same way as any table in SchemaA. Fortunately, Oracle provides (mostly) complete dependency information in the dictionary views. Before we actually read the information on all the tables and columns in the database, we can get dependency information on all the objects that are either pointed at by objects in the schemas we’re populating, or point to objects in the schemas we’re populating (think about what would happen if SchemaB was being explicitly populated instead), with a suitable query on all_constraints (for foreign key relationships) and all_dependencies (for most other types of dependencies eg a function using another function). The extra objects found can then be included in the actual object population, and the sync wizard then has enough information to figure out the right thing to do when we get to actually synchronize the objects. Unfortunately, this isn’t enough. 2. Dependency chains The solution above will only get the immediate dependencies of objects in populated schemas. What if there’s a chain of dependencies? A.tbl1 -> B.tbl1 -> C.tbl1 -> D.tbl1 If we’re only populating SchemaA, the implementation above will only include B.tbl1 in the dependent objects list, whereas we might need to know about C.tbl1 and D.tbl1 as well, in order to ensure a modification on A.tbl1 can succeed. What we actually need is a graph traversal on the dependency graph that all_dependencies represents. Fortunately, we don’t have to read all the database dependency information from the server and run the graph traversal on the client computer, as Oracle provides a method of doing this in SQL – CONNECT BY. So, we can put all the dependencies we want to include together in big bag with UNION ALL, then run a SELECT ... CONNECT BY on it, starting with objects in the schema we’re populating. We should end up with all the objects that might be affected by modifications in the initial schema we’re populating. Good solution? Well, no. For one thing, it’s sloooooow. all_dependencies, on my test databases, has got over 110,000 rows in it, and the entire query, for which Oracle was creating a temporary table to hold the big bag of graph edges, was often taking upwards of two minutes. This is too long, and would only get worse for large databases. But it had some more fundamental problems than just performance. 3. Comparison dependencies Consider the following schema: SOURCE   TARGET CREATE TABLE SchemaA.Table1 ( Col1 NUMBER REFERENCES SchemaB.Table1(col1));   CREATE TABLE SchemaA.Table1 ( Col1 VARCHAR2(100)); CREATE TABLE SchemaB.Table1 ( Col1 NUMBER PRIMARY KEY);   CREATE TABLE SchemaB.Table1 ( Col1 VARCHAR2(100)); What will happen if we used the dependency algorithm above on the source & target database? Well, SchemaA.Table1 has a foreign key reference to SchemaB.Table1, so that will be included in the source database population. On the target, SchemaA.Table1 has no such reference. Therefore SchemaB.Table1 will not be included in the target database population. In the resulting comparison of the two objects models, what you will end up with is: SOURCE  TARGET SchemaA.Table1 -> SchemaA.Table1 SchemaB.Table1 -> (no object exists) When this comparison is synchronized, we will see that SchemaB.Table1 does not exist, so we will try the following sequence of actions: Create SchemaB.Table1 Rebuild SchemaA.Table1, with foreign key to SchemaB.Table1 Oops. Because the dependencies are only followed within a single database, we’ve tried to create an object that already exists. To fix this we can include any objects found as dependencies in the source or target databases in the object population of both databases. SchemaB.Table1 will then be included in the target database population, and we won’t try and create objects that already exist. All good? Well, consider the following schema (again, only explicitly populating SchemaA, and synchronizing SchemaA.Table1): SOURCE   TARGET CREATE TABLE SchemaA.Table1 ( Col1 NUMBER REFERENCES SchemaB.Table1(col1));   CREATE TABLE SchemaA.Table1 ( Col1 VARCHAR2(100)); CREATE TABLE SchemaB.Table1 ( Col1 NUMBER PRIMARY KEY);   CREATE TABLE SchemaB.Table1 ( Col1 VARCHAR2(100) PRIMARY KEY); CREATE TABLE SchemaC.Table1 ( Col1 NUMBER);   CREATE TABLE SchemaC.Table1 ( Col1 VARCHAR2(100) REFERENCES SchemaB.Table1); Although we’re now including SchemaB.Table1 on both sides of the comparison, there’s a third table (SchemaC.Table1) that we don’t know about that will cause the rebuild of SchemaB.Table1 to fail if we try and synchronize SchemaA.Table1. That’s because we’re only running the dependency query on the schemas we’re explicitly populating; to solve this issue, we would have to run the dependency query again, but this time starting the graph traversal from the objects found in the other database. Furthermore, this dependency chain could be arbitrarily extended.This leads us to the following algorithm for finding all the dependencies of a comparison: Find initial dependencies of schemas the user has selected to compare on the source and target Include these objects in both the source and target object populations Run the dependency query on the source, starting with the objects found as dependents on the target, and vice versa Repeat 2 & 3 until no more objects are found For the schema above, this will result in the following sequence of actions: Find initial dependenciesSchemaA.Table1 -> SchemaB.Table1 found on sourceNo objects found on target Include objects in both source and targetSchemaB.Table1 included in source and target Run dependency query, starting with found objectsNo objects to start with on sourceSchemaB.Table1 -> SchemaC.Table1 found on target Include objects in both source and targetSchemaC.Table1 included in source and target Run dependency query on found objectsNo objects found in sourceNo objects to start with in target Stop This will ensure that we include all the necessary objects to make any synchronization work. However, there is still the issue of query performance; the CONNECT BY on the entire database dependency graph is still too slow. After much sitting down and drawing complicated diagrams, we decided to move the graph traversal algorithm from the server onto the client (which turned out to run much faster on the client than on the server); and to ensure we don’t read the entire dependency graph onto the client we also pull the graph across in bits – we start off with dependency edges involving schemas selected for explicit population, and whenever the graph traversal comes across a dependency reference to a schema we don’t yet know about a thunk is hit that pulls in the dependency information for that schema from the database. We continue passing more dependent objects back and forth between the source and target until no more dependency references are found. This gives us the list of all the extra objects to populate in the source and target, and object population can then proceed. 4. Object blacklists and fast dependencies When we tested this solution, we were puzzled in that in some of our databases most of the system schemas (WMSYS, ORDSYS, EXFSYS, XDB, etc) were being pulled in, and this was increasing the database registration and comparison time quite significantly. After debugging, we discovered that the culprits were database tables that used one of the Oracle PL/SQL types (eg the SDO_GEOMETRY spatial type). These were creating a dependency chain from the database tables we were populating to the system schemas, and hence pulling in most of the system objects in that schema. To solve this we introduced blacklists of objects we wouldn’t follow any dependency chain through. As well as the Oracle-supplied PL/SQL types (MDSYS.SDO_GEOMETRY, ORDSYS.SI_COLOR, among others) we also decided to blacklist the entire PUBLIC and SYS schemas, as any references to those would likely lead to a blow up in the dependency graph that would massively increase the database registration time, and could result in the client running out of memory. Even with these improvements, each dependency query was taking upwards of a minute. We discovered from Oracle execution plans that there were some columns, with dependency information we required, that were querying system tables with no indexes on them! To cut a long story short, running the following query: SELECT * FROM all_tab_cols WHERE data_type_owner = ‘XDB’; results in a full table scan of the SYS.COL$ system table! This single clause was responsible for over half the execution time of the dependency query. Hence, the ‘Ignore slow dependencies’ option was born – not querying this and a couple of similar clauses to drastically speed up the dependency query execution time, at the expense of producing incorrect sync scripts in rare edge cases. Needless to say, along with the sync script action ordering, the dependency code in the database registration is one of the most complicated and most rewritten parts of the Schema Compare for Oracle engine. The beta of Schema Compare for Oracle is out now; if you find a bug in it, please do tell us so we can get it fixed!

    Read the article

  • Changing LDAP schema casts Confluence AD integration unoperable

    - by Maxim V. Pavlov
    I have had our instance of Atlassian Confluence configured to be integrated with our Active Directory. In AD, all the users were being created under default Users folder in Active Directory Users and Computers. We have decided to introduce cleaner separation and have created an Organizational Units structure in AD. Under root we have created Managed OU, and under it - Users OU and all user accounts were moved under Users OU. Now I though that to let the Confluence AD integration engine "know" where to look for user accounts now, I only need to adjust the BaseDN and prepand it with ou=Managed so it is aware that it is looking for cn=Users but under ou=Managed. That didn't work. How should I adjust LDAP schema root in a client application for it to be able to look for users in OU that then in a default folder.

    Read the article

  • Whole map design vs. tiles array design

    - by Mikalichov
    I am working on a 2D RPG, which will feature the usual dungeon/town maps (pre-generated). I am using tiles, that I will then combine to make the maps. My original plan was to assemble the tiles using Photoshop, or some other graphic program, in order to have one bigger picture that I could then use as a map. However, I have read on several places people talking about how they used arrays to build their map in the engine (so you give an array of x tiles to your engine, and it assemble them as a map). I can understand how it's done, but it seems a lot more complicated to implement, and I can't see obvious avantages. What is the most common method, and what are advantages/disadvantages of each?

    Read the article

  • Better Understand the 'Strategy' Design Pattern

    - by Imran Omar Bukhsh
    Greetings Hope you all are doing great. I have been interested in design patterns for a while and started reading 'Head First Design Patterns'. I started with the first pattern called the 'Strategy' pattern. I went through the problem outlined in the images below and first tried to propose a solution myself so I could really grasp the importance of the pattern. So my question is that why is my solution ( below ) to the problem outlined in the images below not good enough. What are the good / bad points of my solution vs the pattern? What makes the pattern clearly the only viable solution ? Thanks for you input, hope it will help me better understand the pattern. MY SOLUTION Parent Class: DUCK <?php class Duck { public $swimmable; public $quackable; public $flyable; function display() { echo "A Duck Looks Like This<BR/>"; } function quack() { if($this->quackable==1) { echo("Quack<BR/>"); } } function swim() { if($this->swimmable==1) { echo("Swim<BR/>"); } } function fly() { if($this->flyable==1) { echo("Fly<BR/>"); } } } ?> INHERITING CLASS: MallardDuck <?php class MallardDuck extends Duck { function MallardDuck() { $this->quackable = 1; $this->swimmable = 1; } function display() { echo "A Mallard Duck Looks Like This<BR/>"; } } ?> INHERITING CLASS: WoddenDecoyDuck <?php class WoddenDecoyDuck extends Duck { function woddendecoyduck() { $this->quackable = 0; $this->swimmable = 0; } function display() { echo "A Wooden Decoy Duck Looks Like This<BR/>"; } } Thanking you for your input. Imran

    Read the article

  • Game software design

    - by L. De Leo
    I have been working on a simple implementation of a card game in object oriented Python/HTML/Javascript and building on the top of Django. At this point the game is in its final stage of development but, while spotting a big issue about how I was keeping the application state (basically using a global variable), I reached the point that I'm stuck. The thing is that ignoring the design flaw, in a single-threaded environment such as under the Django development server, the game works perfectly. While I tried to design classes cleanly and keep methods short I now have in front of me an issue that has been keeping me busy for the last 2 days and that countless print statements and visual debugging hasn't helped me spot. The reason I think has to do with some side-effects of functions and to solve it I've been wondering if maybe refactoring the code entirely with static classes that keep no state and just passing the state around might be a good option to keep side-effects under control. Or maybe trying to program it in a functional programming style (although I'm not sure Python allows for a purely functional style). I feel that now there's already too many layers that the software (which I plan to make incredibly more complex by adding non trivial features) has already become unmanageable. How would you suggest I re-take control of my code-base that (despite being still only at < 1000 LOC) seems to have taken a life of its own?

    Read the article

  • How far to go with Domain Driven Design?

    - by synti
    I've read a little about domain driven design and the usage of a rich domain model, as described by Martin Fowler, and I've decided to put it in practice in a personal project, instead of using transaction scripts. Everything went fine until UI implementation started. The thing is some views will use rich components that are backed up by unusual models and, thus, I must transform the domain model into what is used by those components. And that transformation is specially "complex" in the view-to-domain portion, up to the point that some business logic is involved. Wich brings me to the questioning: where should I do these adaptations? So far I've got the following conclusions: Doing it in the presentation layer is good because, well, if that layer imposes restrictions in it's model, then it should be the one to handle them. But it's bad because there'll be some business leakage. If I do it on the services objects (controllers, actions, whatever), then it'd be good because there won't be any change to the domain API just because of presentation layer, but it's bad because then I'd have transaction scripts, wich is not the intended design. Finally, if I do it on the domain model, there'd be no leakage of business logic at all. But in the future I could expect an explosion of the API into a series of methods designed just to handle that view-model <- domain-model adaptation. I hope I could make myself clear on this.

    Read the article

  • DDD Model Design and Repository Persistence Performance Considerations

    - by agarhy
    So I have been reading about DDD for some time and trying to figure out the best approach on several issues. I tend to agree that I should design my model in a persistent agnostic manner. And that repositories should load and persist my models in valid states. But are these approaches realistic practically? I mean its normal for a model to hold a reference to a collection of another type. Persisting that model should mean persist the entire collection. Fine. But do I really need to load the entire collection every time I load the model? Probably not. So I can have specialized repositories. Some that load maybe a subset of the object graph via DTOs and others that load the entire object graph. But when do I use which? If I have DTOs, what's stopping client code from directly calling them and completely bypassing the model? I can have mappers and factories to create my models from DTOs maybe? But depending on the design of my models that might not always work. Or it might not allow my models to be created in a valid state. What's the correct approach here?

    Read the article

  • Architecture design with MyBatis mappers

    - by Wolf
    I am creating rest web service for providing data. I am using Spring MVC for handling rest requests, and MyBatis for data access. Application should be designed in the way that it should be easy to change the data access implementation (for example to hibernate or something else) and it has to be fast (so I am trying to avoid unnecessary overcomplication of design). Now my question is about the general design of layers. I would normally use DAO interface and then different implementations for different data access strategies, but MyBatis uses interfaces to access the data. So I can think of 2 possible models but I am not sure which one is better or if there is any other nice way: Controller layer - uses Service layer interfaces services are then implemented for each data access stretegy - for example for mybatis: service implementation uses Mapper classes to access data and do whatever it needs to do with them and sends them to controller layer Controller layer - uses Service layer - service layer uses DAO interfaces DAOs are then implemented for each data access strategy - for example for mybatis: DAO class uses mapper interface to access data and sends them to service layer, service layer then do whatever it needs to do with them and sends them to controller layer I prefer the first strategy as it seems to be less complicated, but then I would have to write all of the service code for another data access again. What do you think? Thank You

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 8 9 10 11 12 13 14 15 16 17 18 19  | Next Page >