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  • Power Pivot - Average time per item

    - by Username
    I'm trying to calculate on average, how long it takes to make each item. Here is the data table: Date Item Quantity Operator 01/01/2014 Item1 3 John 01/01/2014 Item2 5 John 02/01/2014 Item1 7 Bob 02/01/2014 Item2 4 John 03/01/2014 Item1 2 Bob 07/01/2014 Item2 3 John On 01/01/2014 John made 3 of Item 1 and 5 of Item 2. If we only had the first 2 rows we can guess that it takes 0.375 days to make Item 1 and 0.625 days to make Item 2. I want to be able to calculate this on average using all the data and taking in to account the operators obviously working on different items. Thank you

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  • SAN shows as unallocated in Windows Server

    - by Gareth Ferneyhough
    Hello. We have a SAN drive that shows as unallocated in Windows Server 2008. I believe it is a raid 10 with 4+ disks. The disks are in good health. I think a server that we rebuilt tried to connect to the drive and re-initialized them, or re-wrote the partition table. (excuse my poor terminology). We ran TestDisk on the drive and it shows no partitions, so now we are doing a quick search (which is not so quick). Can anyone else suggest anything? Thanks, Gareth

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  • Excel Pivot Tables -- Divide Numerical Column Data into Ranges

    - by ktm5124
    Hi, I have an Excel spreadsheet with a column called "Time Elapsed" that stores the number of days it took to complete a task. I would like to make a pivot table out of this spreadsheet where I divide the "Time Elapsed" column into ranges, e.g., how many tasks took 0 to 4 days to complete how many tasks took 5 to 9 days how many took 10 to 14 days how many took 15+ days Do I have to create new columns in my spreadsheet dedicated to each interval (0 to 4, 5 to 9, etc.) or can I use some feature of pivot tables to separate my one "Time Elapsed" column into intervals? Thanks in advance.

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  • How to sort time column by value instead of alphabetically

    - by Turch
    I'm creating a pivot table by connecting to an SSAS tabular model (Data - From Other Sources - From Analysis Services) . The model has a "time" column that I want to sort by. The default (database) sorting is earliest to latest: When I click the triangle next to 'Row Labels' and select "Sort A to Z", I get alphabetically sorted times: How can I get the times to sort by time? Changing the number format from "General" to "Time" does nothing. The times aren't stored as text either - the data type of the column in the SSAS model is Auto (Date)

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  • How can I get SQL Server transactions to use record-level locks?

    - by Joe White
    We have an application that was originally written as a desktop app, lo these many years ago. It starts a transaction whenever you open an edit screen, and commits if you click OK, or rolls back if you click Cancel. This worked okay for a desktop app, but now we're trying to move to ADO.NET and SQL Server, and the long-running transactions are problematic. I found that we'll have a problem when multiple users are all trying to edit (different subsets of) the same table at the same time. In our old database, each user's transaction would acquire record-level locks to every record they modified during their transaction; since different users were editing different records, everyone gets their own locks and everything works. But in SQL Server, as soon as one user edits a record inside a transaction, SQL Server appears to get a lock on the entire table. When a second user tries to edit a different record in the same table, the second user's app simply locks up, because the SqlConnection blocks until the first user either commits or rolls back. I'm aware that long-running transactions are bad, and I know that the best solution would be to change these screens so that they no longer keep transactions open for a long time. But since that would mean some invasive and risky changes, I also want to research whether there's a way to get this code up and running as-is, just so I know what my options are. How can I get two different users' transactions in SQL Server to lock individual records instead of the entire table? Here's a quick-and-dirty console app that illustrates the issue. I've created a database called "test1", with one table called "Values" that just has ID (int) and Value (nvarchar) columns. If you run the app, it asks for an ID to modify, starts a transaction, modifies that record, and then leaves the transaction open until you press ENTER. I want to be able to start the program and tell it to update ID 1; let it get its transaction and modify the record; start a second copy of the program and tell it to update ID 2; have it able to update (and commit) while the first app's transaction is still open. Currently it freezes at step 4, until I go back to the first copy of the app and close it or press ENTER so it commits. The call to command.ExecuteNonQuery blocks until the first connection is closed. public static void Main() { Console.Write("ID to update: "); var id = int.Parse(Console.ReadLine()); Console.WriteLine("Starting transaction"); using (var scope = new TransactionScope()) using (var connection = new SqlConnection(@"Data Source=localhost\sqlexpress;Initial Catalog=test1;Integrated Security=True")) { connection.Open(); var command = connection.CreateCommand(); command.CommandText = "UPDATE [Values] SET Value = 'Value' WHERE ID = " + id; Console.WriteLine("Updating record"); command.ExecuteNonQuery(); Console.Write("Press ENTER to end transaction: "); Console.ReadLine(); scope.Complete(); } } Here are some things I've already tried, with no change in behavior: Changing the transaction isolation level to "read uncommitted" Specifying a "WITH (ROWLOCK)" on the UPDATE statement

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  • Patterns for implementing field change tracking.

    - by David
    Hi all For one of my recent projects, I had to implement field change tracking. So anytime the user changed a value of a field, the change was recorded in order to allow full auditing of changes. In the database, I implemented this as a single table 'FieldChanges' with the following fields: TableName, FieldName, RecordId, DateOfChange, ChangedBy, IntValue, TextValue, DateTimeValue, BoolValue. The sproc saving changes to an object determines for each field whether it has been changed and inserts a record into FieldChanges if it has: if the type of the changed field is int, it records it in the IntValue field in the FieldChanges table, etc. This means that for any field in any table with any id value, I can query the FieldChanges table to get a list of changes. This works quite well but is a bit clumsy. Can anyone else who has implemented similar functionality suggest a better approach, and why they think it's better? I'd be really interested - thanks. David

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  • Legit? Two foreign keys referencing the same primary key.

    - by Ryan
    Hi All, I'm a web developer and have recently started a project with a company. Currently, I'm working with their DBA on getting the schema laid out for the site, and we've come to a disagreement regarding the design on a couple tables, and I'd like some opinions on the matter. Basically, we are working on a site that will implement a "friends" network. All users of the site will be contained in a table tblUsers with (PersonID int identity PK, etc). What I am wanting to do is to create a second table, tblNetwork, that will hold all of the relationships between users, with (NetworkID int identity PK, Owners_PersonID int FK, Friends_PersonID int FK, etc). Or conversely, remove the NetworkID, and have both the Owners_PersonID and Friends_PersonID shared as the Primary key. This is where the DBA has his problem. Saying that "he would only implement this kind of architecture in a data warehousing schema, and not for a website, and this is just another example of web developers trying to take the easy way out." Now obviously, his remark was a bit inflammatory, and that have helped motivate me to find an suitable answer, but more so, I'd just like to know how to do it right. I've been developing databases and programming for over 10 years, have worked with some top-notch minds, and have never heard this kind of argument. What the DBA is wanting to do is instead of storing both the Owners_PersonId and Friends_PersonId in the same table, is to create a third table tblFriends to store the Friends_PersonId, and have the tblNetwork have (NetworkID int identity PK, Owner_PersonID int FK, FriendsID int FK(from TBLFriends)). All that tblFriends would house would be (FriendsID int identity PK, Friends_PersonID(related back to Persons)). To me, creating the third table is just excessive in nature, and does nothing but create an alias for the Friends_PersonID, and cause me to have to add (what I view as unneeded) joins to all my queries, not to mention the extra cycles that will be necessary to perform the join on every query. Thanks for reading, appreciate comments. Ryan

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  • Querying a Cassandra column family for rows that have not been updated in X days

    - by knorv
    I'm moving an existing MySQL based application over to Cassandra. So far finding the equivalent Cassandra data model has been quite easy, but I've stumbled on the following problem for which I'd appreciate some input: Consider a MySQL table holding millions of entities: CREATE TABLE entities ( id INT AUTO_INCREMENT NOT NULL, entity_information VARCHAR(...), entity_last_updated DATETIME, PRIMARY KEY (id), KEY (entity_last_updated) ); The table is regularly queried for entities that need to be updated: SELECT id FROM entities WHERE entity_last_updated IS NULL OR entity_last_updated < DATE_ADD(NOW(), INTERVAL -7*24 HOUR) ORDER BY entity_last_updated ASC; The entities returned by this queries are then updated using the following query: UPDATE entities SET entity_information = ?, entity_last_updated = NOW() WHERE id = ?; What would be the corresponding Cassandra data model that would allow me to store the given information and effectively query the entities table for entities that need to be updated (that is: entities that have not been updated in the last seven days)?

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  • Storing Preferences/One-to-One Relationships in Database

    - by LnDCobra
    What is the best way to store settings for certain objects in my database? Method one: Using a single table Table: Company {CompanyID, CompanyName, AutoEmail, AutoEmailAddress, AutoPrint, AutoPrintPrinter} Method two: Using two tables Table Company {CompanyID, COmpanyName} Table2 CompanySettings{CompanyID, utoEmail, AutoEmailAddress, AutoPrint, AutoPrintPrinter}

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  • Best pattern for storing (product) attributes in SQL Server

    - by EdH
    We are starting a new project where we need to store product and many product attributes in a database. The technology stack is MS SQL 2008 and Entity Framework 4.0 / LINQ for data access. The products (and Products Table) are pretty straightforward (a SKU, manufacturer, price, etc..). However there are also many attributes to store with each product (think industrial widgets). These may range from color to certification(s) to pipe size. Every product may have different attributes, and some may have multiples of the same attribute (Ex: Certifications). The current proposal is that we will basically have a name/value pair table with a FK back to the product ID in each row. An example of the attributes Table may look like this: ProdID AttributeName AttributeValue 123 Color Blue 123 FittingSize 1.25 123 Certification AS1111 123 Certification EE2212 123 Certification FM.3 456 Pipe 11 678 Color Red 999 Certification AE1111 ... Note: Attribute name would likely come from a lookup table or enum. So the main question here is: Is this the best pattern for doing something like this? How will the performance be? Queries will be based on a JOIN of the product and attributes table, and generally need many WHEREs to filter on specific attributes - the most common search will be to find a product based on a set of known/desired attributes. If anyone has any suggestions or a better pattern for this type of data, please let me know. Thanks! -Ed

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  • database splitting; multiple tables

    - by Ben
    I am coding a classifieds ad web app. What is the optimal way to structure the database for this? Because of the high repeatability, would it be faster (in terms of searching/indexing) to have a separate table in the database for each city? Or would it be okay to just have one table for every city (it would have a lot of rows..). The classifieds table has id, user_id, city_name, category,[description and detail fields].

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  • recursive delete trigger and ON DELETE CASCADE contraints are not deleting everything

    - by bitbonk
    I have a very simple datamodel that represents a tree structure: The RootEntity is the root of such a tree, it can contain children of type ContainerEntity and of type AtomEntity. The type ContainerEntity again can contain children of type ContainerEntity and of type AtomEntity but can not contain children of type RootEntity. Children are referenced in a well known order. The DB model for this is below. My problem now is that when I delete a RootEntity I want all children to be deleted recursively. I have create foreign key with CASCADE DELETE and two delete triggers for this. But it is not deleting everything, it always leaves some items in the ContainerEntity, AtomEntity, ContainerEntity_Children and AtomEntity_Children tables. Seemling beginning with the recursionlevel of 3. CREATE TABLE RootEntity ( Id UNIQUEIDENTIFIER NOT NULL, Name VARCHAR(500) NOT NULL, CONSTRAINT PK_RootEntity PRIMARY KEY NONCLUSTERED (Id), ); CREATE TABLE ContainerEntity ( Id UNIQUEIDENTIFIER NOT NULL, Name VARCHAR(500) NOT NULL, CONSTRAINT PK_ContainerEntity PRIMARY KEY NONCLUSTERED (Id), ); CREATE TABLE AtomEntity ( Id UNIQUEIDENTIFIER NOT NULL, Name VARCHAR(500) NOT NULL, CONSTRAINT PK_AtomEntity PRIMARY KEY NONCLUSTERED (Id), ); CREATE TABLE RootEntity_Children ( ParentId UNIQUEIDENTIFIER NOT NULL, OrderIndex INT NOT NULL, ChildContainerEntityId UNIQUEIDENTIFIER NULL, ChildAtomEntityId UNIQUEIDENTIFIER NULL, ChildIsContainerEntity BIT NOT NULL, CONSTRAINT PK_RootEntity_Children PRIMARY KEY NONCLUSTERED (ParentId, OrderIndex), -- foreign key to parent RootEntity CONSTRAINT FK_RootEntiry_Children__RootEntity FOREIGN KEY (ParentId) REFERENCES RootEntity (Id) ON DELETE CASCADE, -- foreign key to referenced (child) ContainerEntity CONSTRAINT FK_RootEntiry_Children__ContainerEntity FOREIGN KEY (ChildContainerEntityId) REFERENCES ContainerEntity (Id) ON DELETE CASCADE, -- foreign key to referenced (child) AtomEntity CONSTRAINT FK_RootEntiry_Children__AtomEntity FOREIGN KEY (ChildAtomEntityId) REFERENCES AtomEntity (Id) ON DELETE CASCADE, ); CREATE TABLE ContainerEntity_Children ( ParentId UNIQUEIDENTIFIER NOT NULL, OrderIndex INT NOT NULL, ChildContainerEntityId UNIQUEIDENTIFIER NULL, ChildAtomEntityId UNIQUEIDENTIFIER NULL, ChildIsContainerEntity BIT NOT NULL, CONSTRAINT PK_ContainerEntity_Children PRIMARY KEY NONCLUSTERED (ParentId, OrderIndex), -- foreign key to parent ContainerEntity CONSTRAINT FK_ContainerEntity_Children__RootEntity FOREIGN KEY (ParentId) REFERENCES ContainerEntity (Id) ON DELETE CASCADE, -- foreign key to referenced (child) ContainerEntity CONSTRAINT FK_ContainerEntity_Children__ContainerEntity FOREIGN KEY (ChildContainerEntityId) REFERENCES ContainerEntity (Id) ON DELETE CASCADE, -- foreign key to referenced (child) AtomEntity CONSTRAINT FK_ContainerEntity_Children__AtomEntity FOREIGN KEY (ChildAtomEntityId) REFERENCES AtomEntity (Id) ON DELETE CASCADE, ); CREATE TRIGGER Delete_RootEntity_Children ON RootEntity_Children FOR DELETE AS DELETE FROM ContainerEntity WHERE Id IN (SELECT ChildContainerEntityId FROM deleted) DELETE FROM AtomEntity WHERE Id IN (SELECT ChildAtomEntityId FROM deleted) GO CREATE TRIGGER Delete_ContainerEntiy_Children ON ContainerEntity_Children FOR DELETE AS DELETE FROM ContainerEntity WHERE Id IN (SELECT ChildContainerEntityId FROM deleted) DELETE FROM AtomEntity WHERE Id IN (SELECT ChildAtomEntityId FROM deleted) GO

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  • Any simple approaches for managing customer data change requests for global reference files?

    - by Kelly Duke
    For the first time, I am developing in an environment in which there is a central repository for a number of different industry standard reference data tables and many different customers who need to select records from these industry standard reference data tables to fill in foreign key information for their customer specific records. Because these industry standard reference files are utilized by all customers, I want to reserve Create/Update/Delete access to these records for global product administrators. However, I would like to implement a (semi-)automated interface by which specific customers could request record additions, deletions or modifications to any of the industry standard reference files that are shared among all customers. I know I need something like a "data change request" table specifying: user id, user request datetime, request type (insert, modify, delete), a user entered text explanation of the change request, the user request's current status (pending, declined, completed), admin resolution datetime, admin id, an admin entered text description of the resolution, etc. What I can't figure out is how to elegantly handle the fact that these data change requests could apply to dozens of different tables with differing table column definitions. I would like to give the customer users making these data change requests a convenient way to enter their proposed record additions/modifications directly into CRUD screens that look very much like the reference table CRUD screens they don't have write/delete permissions for (with an additional text explanation and perhaps request priority field). I would also like to give the global admins a tool that allows them to view all the outstanding data change requests for the users they oversee sorted by date requested or user/date requested. Upon selecting a data change request record off the list, the admin would be directed to another CRUD screen that would be populated with the fields the customer users requested for the new/modified industry standard reference table record along with customer's text explanation, the request status and the text resolution explanation field. At this point the admin could accept/edit/reject the requested change and if accepted the affected industry standard reference file would be automatically updated with the appropriate fields and the data change request record's status, text resolution explanation and resolution datetime would all also be appropriately updated. However, I want to keep the actual production reference tables as simple as possible and free from these extraneous and typically null customer change request fields. I'd also like the data change request file to aggregate all data change requests across all the reference tables yet somehow "point to" the specific reference table and primary key in question for modification & deletion requests or the specific reference table and associated customer user entered field values in question for record creation requests. Does anybody have any ideas of how to design something like this effectively? Is there a cleaner, simpler way I am missing? Thank you so much for reading.

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  • How to design this ?

    - by Akku
    how can i make this entire process as 1 single event??? http://code.google.com/apis/visualization/documentation/dev/dsl_get_started.html and draw the chart on single click? I am new to servlets please guide me When a user clicks the "go " button with some input. The data goes to the servlet say "Test3". The servlet processes the data by the user and generates/feeds the data table dynamically Then I call the html page to draw the chart as shown in the tutorial link above. The problem is when I call the servlet it gives me a long json string in the browser as given in the tutorials "google.visualization.Query.setResponse({version:'0.6',status:'ok',sig:'1333639331',table:{cols:[{............................" Then when i manually call the html page to draw the chart i am see the chart. But when I call html page directly using the request dispatcher via the servlet I dont get the result. This is my code and o/p...... I need sugession as to how should be my approach to call the chart public class Test3 extends HttpServlet implements DataTableGenerator { protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { DataSourceHelper.executeDataSourceServletFlow(request, response, this , isRestrictedAccessMode() ); RequestDispatcher rd; rd = request.getRequestDispatcher("new.html");// it call's the html page which draws the chart as per the data added by the servlet..... rd.include(request, response);//forward(request, response); @Override public Capabilities getCapabilities() { return Capabilities.NONE; } protected boolean isRestrictedAccessMode() { return false; } @Override public DataTable generateDataTable(Query query, HttpServletRequest request) { // Create a data table. DataTable data = new DataTable(); ArrayList<ColumnDescription> cd = new ArrayList<ColumnDescription>(); cd.add(new ColumnDescription("name", ValueType.TEXT, "Animal name")); cd.add......... I get the following result along with unprocessed html page google.visualization.Query.setResponse({version:'0.6',statu..... <html> <head> <title>Getting Started Example</title> .... Entire html page as it is on the Browser. What I need is when a user clicks the go button the servlet should process the data and call the html page to draw the chart....Without the json string appearing on the browser.(all in one user click) What should be my approach or how should i design this.... there are no error in the code. since when i run the servlet i get the json string on the browser and then when i run the html page manually i get the chart drawn. So how can I do (servlet processing + html page drawing chart as final result) at one go without the long json string appearing on the browser. There is no problem with the html code....

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  • Style guide for database metadata naming

    - by Nulldevice
    We want to establish some database metadata naming rules in our new project. For example: tables are named as nouns in a plural form (courses, books, lessons) if present, an adjective goes before a noun in a table name and is separated by an underscore (red_books, new_lessons) table index column is always named "id" foreign key names are derived from a table name with suffix _id (book_id, red_book_id) so on Does someone know any guide like this?

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  • How to record different authentication types (username / password vs token based) in audit log

    - by RM
    I have two types of users for my system, normal human users with a username / password, and delegation authorized accounts through OAuth (i.e. using a token identifier). The information that is stored for each is quite different, and are managed by different subsytems. They do however interact with the same tables / data within the system, so I need to maintain the audit trail regardless of whether human user, or token-based user modified the data. My solution at the moment is to have a table called something like AuditableIdentity, and then have the two types inheriting off that table (either in the single table, or as two seperate tables with 1 to 1 PK with AuditableIdentity. All operations would use the common AuditableIdentity PK for CreatedBy, ModifiedBy etc columns. There isn't any FK constraint on the audit columns, so any text can go in there, but I want an easy way to easily determine whether it was a human or system that made the change, and joining to the one AuditableIdentity table seems like a clean way to do that? Is there a best practice for this scenario? Is this an appropriate way of approaching the problem - or would you not bother with the common table and just rely on joins (to the two seperate un-related user / token tables) later to determine which user type matches which audit records?

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  • Future proof Primary Key design in postgresql

    - by John P
    I've always used either auto_generated or Sequences in the past for my primary keys. With the current system I'm working on there is the possibility of having to eventually partition the data which has never been a requirement in the past. Knowing that I may need to partition the data in the future, is there any advantage of using UUIDs for PKs instead of the database's built-in sequences? If so, is there a design pattern that can safely generate relatively short keys (say 6 characters instead of the usual long one e6709870-5cbc-11df-a08a-0800200c9a66)? 36^6 keys per-table is more than sufficient for any table I could imagine. I will be using the keys in URLs so conciseness is important.

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  • Is it wise to use temporary tables?

    - by Industrial
    Hi guys, We have a mySQL database table for products. We are utilizing a cache layer to reduce database load, but we think that it's a good idea to minimize the actual data needed to be stored in the cache layer to speed up the application further. All the products in the database, that is visible to visitors have a price attached to them: The prices are stored in a different table, called prices . There are multiple price categories depending on which discount level each visitor (customer) applies to. From time to time, there are campaigns which means that a special price for each product is available. The special prices are stored in a table called specials. Is it a bad to make a temp table that binds the tables together? It would only have the neccessary information and would ofcourse be cached. -------------|-------------|------------ | productId | hasPrice | hasSpecial -------------|-------------|------------ 1 | 1 | 0 2 | 1 | 1 By doing such, it would be super easy to know if the specific product really has a price, without having to iterate through the complete prices or specials table each time a product should be listed or presented. Are temp tables a common thing for web applications or is it just bad design?

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  • Surrogate key for date dimension?

    - by Navin
    There are 2 school of thoughts : Use surrogate key preferbly in the format of YYYYMMDD as this will always be sequential. Eliminate Date dimension surrogate key and use actual date instead. My Questions to experts on dimension modeling are : 1> Which design would you prefer and why ? 2> How should we handle unknown values in each of the cases, Can we simply place NULL in Fact table for unknown dates as Foreign Key can be NULL (if no why)? 3> If we need to partition fact table on date column ,how would we achieve that in case 1. I am inclined towards using actual date and using NULL to represent UNKNOWN dates in fact table , as date related validation on fact can be done without need to look in to dimension table.

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  • best practice - loging events (general) and changes (database)

    - by b0x0rz
    need help with logging all activities on a site as well as database changes. requirements: * should be in database * should be easily searchable by initiator (user name / session id), event (activity type) and event parameters i can think of a database design but either it involves a lot of tables (one per event) so i can log each of the parameters of an event in a separate field OR it involves one table with generic fields (7 int numeric and 7 text types) and log everything in one table with event type field determining what parameter got written where (and hoping that i don't need more than 7 fields of a certain type, or 8 or 9 or whatever number i choose)... example of entries (the usual things): [username] login failed @datetime [username] login successful @datetime [username] changed password @datetime, estimated security of password [low/ok/high/perfect] @datetime [username] clicked result [result number] [result id] after searching for [search string] and got [number of results] @datetime [username] clicked result [result number] [result id] after searching for [search string] and got [number of results] @datetime [username] changed profile name from [old name] to [new name] @datetime [username] verified name with [credit card type] credit card @datetime datbase table [table name] purged of old entries @datetime etc... so anyone dealt with this before? any best practices / links you can share? i've seen it done with the generic solution mentioned above, but somehow that goes against what i learned from database design, but as you can see the sheer number of events that need to be trackable (each user will be able to see this info) is giving me headaches, BUT i do LOVE the one event per table solution more than the generic one. any thoughts? edit: also, is there maybe an authoritative list of such (likely) events somewhere? thnx stack overflow says: the question you're asking appears subjective and is likely to be closed. my answer: probably is subjective, but it is directly related to my issue i have with designing a database / writing my code, so i'd welcome any help. also i tried narrowing down the ideas to 2 so hopefully one of these will prevail, unless there already is an established solution for these kinds of things.

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  • Best practice - logging events (general) and changes (database)

    - by b0x0rz
    need help with logging all activities on a site as well as database changes. requirements: * should be in database * should be easily searchable by initiator (user name / session id), event (activity type) and event parameters i can think of a database design but either it involves a lot of tables (one per event) so i can log each of the parameters of an event in a separate field OR it involves one table with generic fields (7 int numeric and 7 text types) and log everything in one table with event type field determining what parameter got written where (and hoping that i don't need more than 7 fields of a certain type, or 8 or 9 or whatever number i choose)... example of entries (the usual things): [username] login failed @datetime [username] login successful @datetime [username] changed password @datetime, estimated security of password [low/ok/high/perfect] @datetime [username] clicked result [result number] [result id] after searching for [search string] and got [number of results] @datetime [username] clicked result [result number] [result id] after searching for [search string] and got [number of results] @datetime [username] changed profile name from [old name] to [new name] @datetime [username] verified name with [credit card type] credit card @datetime datbase table [table name] purged of old entries @datetime via automated process etc... so anyone dealt with this before? any best practices / links you can share? i've seen it done with the generic solution mentioned above, but somehow that goes against what i learned from database design, but as you can see the sheer number of events that need to be trackable (each user will be able to see this info) is giving me headaches, BUT i do LOVE the one event per table solution more than the generic one. any thoughts? edit: also, is there maybe an authoritative list of such (likely) events somewhere? thnx stack overflow says: the question you're asking appears subjective and is likely to be closed. my answer: probably is subjective, but it is directly related to my issue i have with designing a database / writing my code, so i'd welcome any help. also i tried narrowing down the ideas to 2 so hopefully one of these will prevail, unless there already is an established solution for these kinds of things.

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  • How to model a mutually exclusive relationship in sql server

    - by littlechris
    Hi, I have to add functionality to an existing application and I've run into a data situation that I'm not sure how to model. I am being restricted to the creation of new tables and code. If I need to alter the existing structure I think my client may reject the proposal..although if its the only way to get it right this is what I will have to do. I have an Item table that can me link to any number of tables, and these tables may increase over time. The Item can only me linked to one other table, but the record in the other table may have many items linked to it. Examples of the tables/entities being linked to are "Person", "Vehicle", "Building", "Office". These are all separate tables. Example of Items are "Pen", "Stapler", "Cushion", "Tyre", "A4 Paper", "Plastic Bag", "Poster", "Decoration" For instance a "Poster" may be allocated to a "Person" or "Office" or "Building". In the future if they add a "Conference Room" table it may also be added to that. My intital thoughts are: Item { ID, Name } LinkedItem { ItemID, LinkedToTableName, LinkedToID } The LinkedToTableName field will then allow me to identify the correct table to link to in my code. I'm not overly happy with this solution, but I can't quite think of anything else. Please help! :) Thanks!

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  • Event feed implementation - will it scale?

    - by SlappyTheFish
    Situation: I am currently designing a feed system for a social website whereby each user has a feed of their friends' activities. I have two possible methods how to generate the feeds and I would like to ask which is best in terms of ability to scale. Events from all users are collected in one central database table, event_log. Users are paired as friends in the table friends. The RDBMS we are using is MySQL. Standard method: When a user requests their feed page, the system generates the feed by inner joining event_log with friends. The result is then cached and set to timeout after 5 minutes. Scaling is achieved by varying this timeout. Hypothesised method: A task runs in the background and for each new, unprocessed item in event_log, it creates entries in the database table user_feed pairing that event with all of the users who are friends with the user who initiated the event. One table row pairs one event with one user. The problems with the standard method are well known – what if a lot of people's caches expire at the same time? The solution also does not scale well – the brief is for feeds to update as close to real-time as possible The hypothesised solution in my eyes seems much better; all processing is done offline so no user waits for a page to generate and there are no joins so database tables can be sharded across physical machines. However, if a user has 100,000 friends and creates 20 events in one session, then that results in inserting 2,000,000 rows into the database. Question: The question boils down to two points: Is this worst-case scenario mentioned above problematic, i.e. does table size have an impact on MySQL performance and are there any issues with this mass inserting of data for each event? Is there anything else I have missed?

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  • Insert data in an object to a database.

    - by paul
    I am facing the following design/implementation dilemma. I have a class Customer which is below with getters and setters. I would like to insert the value of the Customer into a "Customer" table of a database. But Customer has an address which is of type "Address". How do I go about inserting this field into the database?(I am using sqlite3). I thought of writing a separate table "Address(customerId,doorNo,city,state,country,pinCode)". But I am having second thoughts about generating the primary key(customerId) which should be same for both the "customer" and "Address" table. Sqlite3 faq states that I can do "Integer Primary Key" to use the field to generate an auto number. But if I do that in customer table, I would have to retrieve the same Id to be used in Address table. This kinda looks wrong to me :-?. There should be an elegant method to solve this. Any ideas would be much appreciated. Thanks in advance. import java.io.*; import java.sql.*; class Customer { private String id; private String name; private Address address; private Connection connection; private ResultSet resultSet; private PreparedStatement preparedStatement; public void insertToDatabase(){ } } class Address{ private String doorNumber; private String streetName; private String cityName; private String districtName; private String stateName; private String countryName; private long pinCode; }

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  • How to structure a database with questions and answers?

    - by Andreas Johannessen
    Hi I am going to make a simple application that uses a database. I could need some guidance on how to structure it. I shall make question program. What I have in mind is. One table with questions One table with the difficulity of the question One table with the category of the question However, what do I do with the answers? Have them as seperate columns in the question-table? It sounds like a bad practice.(Also, where do I have the correct answer) Each question will have 5 answers where only one of them is correct.

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