Hello all, i am new to this topic. i want something like this. i have two tables in my sqliteDatabase one is master and another is child. Now if i delete a record from master suppose i delete a row from master where id=5, then all the records from the child table whose id = 5 deleted automatically. I don't know how to create triggers a...
I'm building an Insurance Site, and will be selling policies online. I'm designing the database at the minute and need some advice on the best way to store the rates I'm using to calculate the premium. There's a clever way of selecting the rates, based on the date the policy was purchased - from a rates table, using like an 'effective ...
I have a need to store a number of ad-hoc figures and constants for calculation. These numbers change periodically but they are different type of values. One might be a balance, a money amount, another might be an interest rate, and yet another might be a ratio of some kind. These numbers are then used in a calculation that involve oth...
I've seen a few questions on this topic already but I'm looking for some insight on the performance differences between these two techniques. For example, lets say I am recording a log of events which will come into the system with a dictionary set of key/value pairs for the specific event. I will record an entry in an Events table with...
are there any or any alternatives available ? ...
Currently I have this in my settings.py file: DEBUG = True LOCAL = True TEMPLATE_DEBUG = DEBUG SITE_TITLE = 'Stack Overflow Question' REMOTE_SITE_URL = "http://************:8080" LOCAL_SITE_URL = "http://************:8000" ADMINS = ( # ('Your Name', '[email protected]'), ) MANAGERS = ADMINS if LOCAL: SITE_URL = LOCAL...
I have borrowed a query and adapted it for my own purposes, but I don't like doing this when I am not entirely sure what it is doing. SQL docs are less than descriptive on this clause. Here is what I borrowed and modified, can you tell me what it is doing basically? (SELECT Id FROM ( SELECT Id ,RAN...
I have a database in which I need to insert batches of data (around 500k records at a time). I was testing with derby and was seeing insert times of about 10-15minutes for this many records (I was doing a batch insert in Java). Does this time seem slow (working on your average laptop)? And are there approaches to speeding it up? thanks...
Hello, I am currently planning a new system in PHP/MySQL and want to make sure my database can handle the amount of data that I am planning to store. One of the features of my new project is a "messages" feature like Facebook. I want to make sure I create the best possible experience for the end user. The website will eventually handle 1...
I want to drop all tables that does not have rows. How to drop all empty tables in SQLite? EDIT I need to do this on a mobile phone (no shell there). On a Windows Mobile phone. ...
ok please be gentle, I am new to WPF and LINQ - I have a strange problem here. I have a search screen and an add/edit screen. I have the add/edit screen bound to a 'CompanyContact' object and a search screen bound to a collection (CompanyContacts). I have a 3 column unique constraint (FirstName, LastName, CompanyId) on the CompanyConta...
Hey everyone, I've recently been playing around with Google's AppEngine and I seem to have gotten stuck. I'm trying to create a query that selects posts that are before a certain date (in this case, the date is now - 1 day). I've tried a few different methods in order to accomplish this, but none have worked. One of which involved conve...
I'm using Extensible Storage Engine and want a unique column (32bits wide). I need the values in this column to be auto assigned by the database I'm hoping to find something like JET_bitIndexUnique that I can mask in? if there isnt such a mask whats the proper way to achieve the goal? ...
I need to get the number of items that have a comment but I cant get this SQL statement to work for me........any advice? Select count(Name) as TotalComments from TableName where comment <> '' order by ID Error Message: Column "TableName.ID" is invalid in the ORDER BY clause because it is not contained in either an aggregate f...
I have some records that I need to store in a database table and I want to distinguish one record from other records on the basis of name field. But as the datatype of name field is varchar, it will effect the performance because comparing varchar data with each other is time consuming process in comparision to a numeric field. So I wa...
I have one field named type in a database table. I want this field to contain a value from a list of pre-defined values. If I use set as the datatype of this field, then it can contain more than one values from the list. What datatype to use, so that It can contain only one value from the list of values (pre-defined)? ...
Scenario: There is a hierarchy of PROCESS. Like PR-2, PR-3 are children of Pr-1, PR-4, PR-5 are children of PR-2 Now the leaf processes (in our case PR-3, PR-4 and PR-5 can be described in terms of series of ACTIVITY Now, ACTIVITY is just a child of PROCESS but has some extra attributes, so Should I make two diff. tables in the d...
I have two classes Parent and Child. class Child extends Parent { private String extraField1; private String extraField2; ... } Child class has 2 extra fields extraField1 and extraField2. Q1. Should I make two diff. tables in the databse: one for Child and other for Parent? or Q1. Should I add two columns in the Parent ...
For multiple running PHP scripts to communicate, what is the least memory intensive solution? Monitor flat files for changes Keep running queries on a DB to check for new data Other techniques I have heard of, but never tried: Shared memory (APC, or core functions) Message queues (Active MQ and company) ...
Hi, this is my third question here, so far excellent responses ^^ I'm having no problems in browsing, editing the data, but insertions... Here is my doubt: In a finance/stock software i have a form to create a new order, naturally i need to insert a new row in t_orders table and insert items in t_orderitems table with orderId field lin...