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How do I find duplicate values in a table in Oracle?
...or a given column and the count of their occurrences in an Oracle database table?
13 Answers
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Why am I getting this error: No mapping specified for the following EntitySet/AssociationSet - Entit
...MX file, you will see that none of the entities have an associated storage table in the SSDL.
That changes when you click the Generate Database From Model context menu item. The confusing part is that this action does more than simply generating a DDL script. In fact, it changes the EDMX file to in...
How to hide columns in HTML table?
I have created a table in ASPX. I want to hide one of the columns based on the requirement but there is no attribute like visible in the HTML table building. How can I solve my problem?
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What's the difference between belongs_to and has_one?
...oreign key is. We can say that a User "has" a Profile because the profiles table has a user_id column. If there was a column called profile_id on the users table, however, we would say that a Profile has a User, and the belongs_to/has_one locations would be swapped.
here is a more detailed explanat...
Working with huge files in VIM
...s a 300GB mysql dump and I wanted to get rid of the DROP and change CREATE TABLE to CREATE TABLE IF NOT EXISTS so didn't want to run two invocations of sed. I wrote this quick Ruby script to dupe the file with those changes:
#!/usr/bin/env ruby
matchers={
%q/^CREATE TABLE `foo`/ => %q/CREA...
'console' is undefined error for Internet Explorer
...le.debug
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* Chrome 41.0.2272.118: debug,error,info,log,warn,dir,dirxml,table,trace,assert,count,markTimeline,profile,profileEnd,time,timeEnd,timeStamp,timeline,timelineEnd,group,groupCollapsed,groupEnd,clear
* Firefox 37.0.1: log,info,warn,error,exception,debug,table,trace,dir,group,groupCollap...
multiprocessing.Pool: When to use apply, apply_async or map?
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Here is an overview in a table format in order to show the differences between Pool.apply, Pool.apply_async, Pool.map and Pool.map_async. When choosing one, you have to take multi-args, concurrency, blocking, and ordering into account:
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Why is LINQ JOIN so much faster than linking with WHERE?
...nce they work directly in memory (Linq to DataSet)
The query with multiple tables and a Where condition actually performs a cartesian product of all the tables, then filters the rows that satisfy the condition. This means the Where condition is evaluated for each combination of rows (n1 * n2 * n3 * ...
Python's json module, converts int dictionary keys to strings
...e.
In Python (and apparently in Lua) the keys to a mapping (dictionary or table, respectively) are object references. In Python they must be immutable types, or they must be objects which implement a __hash__ method. (The Lua docs suggest that it automatically uses the object's ID as a hash/key ...
SQLite Reset Primary Key Field
I have a few tables in SQLite and I am trying to figure out how to reset the auto-incremented database field.
4 Answers
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