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Spring @Transactional - isolation, propagation
...tted: Allows dirty reads.
Read Committed: Does not allow dirty reads.
Repeatable Read: If a row is read twice in the same transaction, the result will always be the same.
Serializable: Performs all transactions in a sequence.
The different levels have different performance characteristics in a mul...
Get local IP address
...xistence of the route to the destination according to the system's routing table and setting the local endpoint accordingly. The last part seems to be undocumented officially but it looks like an integral trait of Berkeley sockets API (a side effect of UDP "connected" state) that works reliably in b...
Fetch the row which has the Max value for a column
Table:
35 Answers
35
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The ALTER TABLE statement conflicted with the FOREIGN KEY constraint
I have a problem when trying to add a foreign key to my tblDomare table; what am I doing wrong here?
18 Answers
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Removing duplicate rows from table in Oracle
I'm testing something in Oracle and populated a table with some sample data, but in the process I accidentally loaded duplicate records, so now I can't create a primary key using some of the columns.
...
Many-to-many relationship with the same model in rails?
...dditional information with the association? (Additional fields in the join table.)
Do the associations need to be implicitly bi-directional?
(If post A is connected to post B, then post B is also connected to post A.)
That leaves four different possibilities. I'll walk over these below.
For refer...
SQL MAX of multiple columns?
...(VALUES (date1), (date2), (date3),...) AS value(v)) as [MaxDate]
FROM [YourTableName]
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Align DIV's to bottom or baseline
...
Use the CSS display values of table and table-cell:
HTML
<html>
<body>
<div class="valign bottom">
<div>
<div>my bottom aligned div 1</div>
<div>my bottom aligned div 2</div>
<...
Postgres: clear entire database before re-creating / re-populating from bash script
...g_dump and pg_restore directly together over a pipe.
To drop and recreate tables, you could use the --clean command-line option for pg_dump to emit SQL commands to clean (drop) database objects prior to (the commands for) creating them. (This will not drop the whole database, just each table/sequen...
Adding :default => true to boolean in existing Rails column
...ribute == nil ? true : false)) }
Update the migration that created this table, so any future builds of the DB will get it right from the onset. Also run the same process on any deployed-instances of the DB.
If using the "new db migration" method, you can do the update of existing nil-values i...