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Removing a model in rails (reverse of “rails g model Title…”)
...oy' on that model, it will delete the migration file, but not the database table. So before run
bundle exec rake db:rollback
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@UniqueConstraint annotation in Java
...@UniqueConstraint annotation is for annotating multiple unique keys at the table level, which is why you get an error when applying it to a field.
References (JPA TopLink):
@UniqueConstraint
@Column
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MySQL Query GROUP BY day / month / year
... Simple complete example: SELECT count(*), record_date FROM anytable WHERE anytable.anycolumn = 'anycondition' GROUP BY YEAR(record_date), month(record_date); note: record_date is a date type TIMESTAMP
– renedet
Jul 25 '17 at 18:35
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How do I drop a function if it already exists?
...'TF')
)
DROP FUNCTION function_name
GO
If you want to avoid the sys* tables, you could instead do (from here in example A):
IF object_id(N'function_name', N'FN') IS NOT NULL
DROP FUNCTION function_name
GO
The main thing to catch is what type of function you are trying to delete (denoted...
How to select bottom most rows?
...olumns
FROM
(
SELECT TOP 200
columns
FROM
My_Table
ORDER BY
a_column DESC
) SQ
ORDER BY
a_column ASC
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PHP code to convert a MySQL query to CSV [closed]
...MINATED BY ',' OPTIONALLY ENCLOSED BY '"'
LINES TERMINATED BY "\n"
FROM my_table;
(the documentation for this is here: http://dev.mysql.com/doc/refman/5.0/en/select.html)
or:
$select = "SELECT * FROM table_name";
$export = mysql_query ( $select ) or die ( "Sql error : " . mysql_error( ) );
$fi...
How to delete from multiple tables in MySQL?
I am trying to delete from a few tables at once. I've done a bit of research, and came up with this
7 Answers
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Remove all spaces from a string in SQL Server
... trim() or worry about multiple spaces for either char or varchar:
create table #t (
c char(8),
v varchar(8))
insert #t (c, v) values
('a a' , 'a a' ),
('a a ' , 'a a ' ),
(' a a' , ' a a' ),
(' a a ', ' a a ')
select
'"' + c + '"' [IN], '"' + replac...
How do I force Postgres to use a particular index?
...meters. See:
Examining index usage
enable_ parameters
These are not suitable for ongoing production use. If you have issues with query plan choice, you should see the documentation for tracking down query performance issues. Don't just set enable_ params and walk away.
Unless you have a very go...
Difference between a theta join, equijoin and natural join
...uijoin will also remove the equality column if they have same name in both tables.
– Vishal R
Nov 13 '14 at 3:42
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