denormalization

问题 Suppose I have a denormalized table that includes an ID and a value that I need to count. Something like this: Tree_ID | ...other columns... | Count_If_True ------------------------------------------------ 1 | ...other values... | True 1 | ...other values... | True 2 | ...other values... | True 2 | ...other values... | True 3 | ...other values... | True In this case, select Tree_ID, count(Count_If_True) from Table group by Tree_ID would show: Tree_ID | count(Count_If_True) -------------------

问题 this is kind of building off a previous question I asked. Suppose I have a denormalized table that looks something like this: Apple_ID | Tree_ID | Orchard_ID | Tree_Height | ...other columns... --------------------------------------------------------------------- 1 | 1 | 1 | 12 | ...other values... --------------------------------------------------------------------- 2 | 1 | 1 | 12 | ...other values... --------------------------------------------------------------------- 3 | 1 | 1 | 12 | ..

问题 I denormalising a OLTP database for use in a DWH. At the moment I am denormalising studygroups. Each studygroup has a key pointing towards 1 project. Each project has a key pointing towards 1 department. Each department has a key pointing towards 1 university. Each universityhas a key pointing to 1 city. Now I know that you are supposed to denormalize the sh*t out your OLTP but in this dwh department will be a dimension on its own. This goes for university also. Would it suffise to add a key

问题 I am using Ruby on Rails 3.0.7 and MySQL 5. In my application I have two database tables, say TABLE1 and TABLE2, and for performance reasons I have denormalizated some data in TABLE2 so that I have repeated values of TABLE1 in that one. Now, in TABLE1 I need to update some of those involved values and, of course, I must update properly also denormalized values in TABLE2. What I can do to update those values in a performant way? That is, if TABLE2 contains a lot of values (1.000.000 or more),

问题 I'm just starting to get my head around non-relational databases, so I'd like to ask some help with converting these traditional SQL/django models into Google App Engine model(s). The example is for event listings, where each event has a category, belongs to a venue, and a venue has a number of photos attached to it. In django, I would model the data like this: class Event(models.Model) title = models.CharField() start = models.DatetimeField() category = models.ForeignKey(Category) venue =

问题 I have the two following tables with services and categories: - servicecat - catid - name : "Category Name" - services - srvid1 : true - srvid2 : true - srvid3 : true - services - srvid - name: "Service Name" - Details: "blabla" - servicecat: - catid1 : true - catid2 : true I'm trying to build a firebaseArray to show when a user click on a service its information and categories. <script> var app = angular.module("sampleApp", ['firebase']); var fb = firebase.database().ref(); app.factory(

问题 I have the two following tables with services and categories: - servicecat - catid - name : "Category Name" - services - srvid1 : true - srvid2 : true - srvid3 : true - services - srvid - name: "Service Name" - Details: "blabla" - servicecat: - catid1 : true - catid2 : true I'm trying to build a firebaseArray to show when a user click on a service its information and categories. <script> var app = angular.module("sampleApp", ['firebase']); var fb = firebase.database().ref(); app.factory(

问题 Given that bigquery is not meant as a platform to denormalize data, can I denormalize the data in google cloud sql prior to importing into bigquery? I have the following tables: Table1 500M rows, Table2 2M rows, Table3 800K rows, I can't denormalize in our existing relational database for various reasons. So I'd like to do a sql dump of the data base, load it into google cloud sql, then use sql join scripts to create one large flat table to be imported into bigquery. Thanks. 回答1: That should

问题 I need to remove diacritics from uppercase characters in a string. Example : Électronique Caméras => Electronique Caméras (only the É is modified, é in Caméras remains as it is) I am using the following method, which removes diacritics only from the uppercase letters, but the reconstructed string looks like this - Electronique Came?ras (é is lost). How can I reconstruct the string properly? public static String removeDiacriticsFromUppercaseLetters(String input) { if (input == null) return

问题 I've started a new project and they have a very normalized database. everything that can be a lookup is stored as the foreign key to the lookup table. this is normalized and fine, but I end up doing 5 table joins for the simplest queries. from va in VehicleActions join vat in VehicleActionTypes on va.VehicleActionTypeId equals vat.VehicleActionTypeId join ai in ActivityInvolvements on va.VehicleActionId equals ai.VehicleActionId join a in Agencies on va.AgencyId equals a.AgencyId join vd in