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Hibernate vs JPA vs JDO - pros and cons of each? [closed]
...ostic and so is not limited to the RDBMS world. With the ground swell of NoSQL at the moment a person would be wise to consider using a persistence standard that avoids locking their apps to the traditional *SQL world. JDO applications can easily be deployed non RDBMS datastores. Full list of suppo...
How can I make SQL case sensitive string comparison on MySQL?
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http://dev.mysql.com/doc/refman/5.0/en/case-sensitivity.html
The default character set and collation are latin1 and latin1_swedish_ci, so nonbinary string comparisons are case insensitive by default. This means that if you search with...
Paste a multi-line Java String in Eclipse [duplicate]
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If your building that SQL in a tool like TOAD or other SQL oriented IDE they often have copy markup to the clipboard. For example, TOAD has a CTRL+M which takes the SQL in your editor and does exactly what you have in your code above. It also c...
svn cleanup: sqlite: database disk image is malformed
... following blog post helped me resolve it:
http://www.polak.ro/svn-e200030-sqlite-database-disk-image-is-malformed.html
You do an integrity check on the sqlite database that keeps track of the repository (/.svn/wc.db):
sqlite3 .svn/wc.db "pragma integrity_check"
That should report some errors.
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Checking oracle sid and database name
...ght be worth noting that not all of the methods give you the same output:
SQL> select sys_context('userenv','db_name') from dual;
SYS_CONTEXT('USERENV','DB_NAME')
--------------------------------------------------------------------------------
orcl
SQL> select ora_database_name from dual;
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How to select rows that have current day's timestamp?
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See the difference: SQL-Fiddle Notice the FILTERED = 25 in the 2nd query.
– ypercubeᵀᴹ
Feb 8 '13 at 12:28
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Unknown Column In Where Clause
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SQL is evaluated backwards, from right to left. So the where clause is parsed and evaluate prior to the select clause. Because of this the aliasing of u_name to user_name has not yet occurred.
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mysql_fetch_array()/mysql_fetch_assoc()/mysql_fetch_row()/mysql_num_rows etc… expects parameter 1 to
I am trying to select data from a MySQL table, but I get one of the following error messages:
31 Answers
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Converting an array of objects to ActiveRecord::Relation
...rray to an ActiveRecord::Relation since a Relation is just a builder for a SQL query and its methods do not operate on actual data.
However, if what you want is a relation then:
for ActiveRecord 3.x, don’t call all and instead call scoped, which will give back a Relation which represents the sa...
NOT IN vs NOT EXISTS
...duce the row count to zero makes cardinality estimation very difficult. If SQL Server assumes that this will happen but in fact there were no NULL rows in the data the rest of the execution plan may be catastrophically worse, if this is just part of a larger query, with inappropriate nested loops ca...