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Rails where condition using NOT NIL
...udes(:bar).where.not(bars: { id: nil })
When working with scopes between tables, I prefer to leverage merge so that I can use existing scopes more easily.
Foo.includes(:bar).merge(Bar.where.not(id: nil))
Also, since includes does not always choose a join strategy, you should use references here...
Center a DIV horizontally and vertically [duplicate]
...
Nice to have a version without table-cell, thanks.
– devlord
Dec 20 '13 at 19:01
...
Managing CSS Explosion
...ible, and grouping related classes as closely as possible.
div.content ul.table_of_contents
div.content ul.table_of_contents li
div.content ul.table_of_contents li h1
div.content ul.table_of_contents li h2
div.content ul.table_of_contents li span.pagenumber
Think of the whole CSS structure as a...
How do I set the time zone of MySQL?
...ed timezones like 'Europe/Helsinki' means that you have to have a timezone table properly populated.)
Keep in mind that +02:00 is an offset. Europe/Berlin is a timezone (that has two offsets) and CEST is a clock time that corresponds to a specific offset.
@@session.time_zone variable
SELECT @@ses...
@UniqueConstraint and @Column(unique = true) in hibernate annotation
...hould have unique values. The same aplies for group.
On the other hand,
@Table(
name = "product_serial_group_mask",
uniqueConstraints = {@UniqueConstraint(columnNames = {"mask", "group"})}
)
Implies that the values of mask + group combined should be unique. That means you can have, for ex...
Stored procedure slow when called from web, fast from Management Studio
... change:
ALTER PROCEDURE [dbo].[sproc]
@param1 int,
AS
SELECT * FROM Table WHERE ID = @param1
to:
ALTER PROCEDURE [dbo].[sproc]
@param1 int,
AS
DECLARE @param1a int
SET @param1a = @param1
SELECT * FROM Table WHERE ID = @param1a
Seems strange, but it fixed my problem.
...
How can I retrieve Id of inserted entity using Entity framework? [closed]
...
Let's consider the following scenario:table1 is supposed to generate an @@identity to use it in table2. Both table1 and table2 are supposed to be in the same transaction for e.g. one SaveChange operation must save both table's data. @@identity won't be generated ...
Select distinct values from a table field
...M. What I want to do is get a list of distinct values within a field on my table .... the equivalent of one of the following:
...
Why would you use Expression rather than Func?
...
@bertl Delegate is what CPU sees (executable code of one architecture), Expression is what compiler sees (merely another format of source code, but still source code).
– codewarrior
May 5 '17 at 9:22
...
MySQL load NULL values from CSV data
... up containing an empty string:
LOAD DATA INFILE '/tmp/testdata.txt'
INTO TABLE moo
FIELDS TERMINATED BY ","
LINES TERMINATED BY "\n"
(one, two, three, @vfour, five)
SET four = NULLIF(@vfour,'')
;
If they're all possibly empty, then you'd read them all into variables and have multiple SET stateme...