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Data access object (DAO) in Java
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}
The employee entities will be persisted into a corresponding Employee table in a database.
A simple DAO interface to handle the database operation required to manipulate an employee entity will be like:
interface EmployeeDAO {
List<Employee> findAll();
List<Employee> findB...
ERROR: permission denied for sequence cities_id_seq using Postgres
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Interesting. I did a GRANT all on the table that my sequence is in, but this doesn't seem to cover the sequence. This also seems to very by OS.
– Kinnard Hockenhull
Jun 7 '14 at 15:48
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Should try…catch go inside or outside a loop?
...ch structures are placed. Internally, they are implemented as a code-range table in a structure that is created when the method is called. While the method is executing, the try/catch structures are completely out of the picture unless a throw occurs, then the location of the error is compared again...
SQL Server Profiler - How to filter trace to only display events from one database?
...lumn and find out the correct values to enter by querying the sysdatabases table in the master database
– Jim Birchall
Nov 10 '08 at 8:39
35
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How to change a nullable column to not nullable in a Rails migration?
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This causes problems when the table already has null values. See my answer
– Rick Smith
Aug 8 '14 at 20:27
5
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Get top n records for each group of grouped results
...fy the group number and add queries for each group:
(
select *
from mytable
where `group` = 1
order by age desc
LIMIT 2
)
UNION ALL
(
select *
from mytable
where `group` = 2
order by age desc
LIMIT 2
)
There are a variety of ways to do this, see this article to determine the...
MAC addresses in JavaScript
...ince any server-side programming language allows you do get access the ARP table, even indirectly (e.g. through a subprocess). I think "client-side language" would work better...
– kirbyfan64sos
Oct 6 '16 at 19:51
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Ruby on Rails: How do I add a not null constraint to an existing column using a migration?
In my Rails (3.2) app, I have a bunch of tables in my database but I forgot to add a few not null constraints. I've googled around but I can't find how to write a migration which adds not null to an existing column.
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Why would introducing useless MOV instructions speed up a tight loop in x86_64 assembly?
...h was being incorrectly predicted due to aliasing in the branch prediction table
moving the branch eliminated the alias and allowed the branch to be predicted correctly
Your Core2 doesn't keep a separate history record for each conditional jump. Instead it keeps a shared history of all conditional...
How to print colored text in Python?
... On Linux, you might want to use tput, like so since it results in more portable code.
– Martin Ueding
Nov 3 '12 at 11:04
3
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