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What is the difference between JOIN and JOIN FETCH when using JPA and Hibernate
...s, JPA will generate a JOIN between the parent entity and the child entity tables in the generated SQL statement.
So, taking your example, when executing this JPQL query:
FROM Employee emp
JOIN emp.department dep
Hibernate is going to generate the following SQL statement:
SELECT emp.*
FROM empl...
Why isn't SQL ANSI-92 standard better adopted over ANSI-89?
...e one and the USING Clause is another. IMHO, the addition of a column to a table shouldn't break code but a NATURAL JOIN breaks in a most egregious fashion. The "best" way to break is by compilation error. For example if you SELECT * somewhere, the addition of a column could fail to compile. The nex...
jquery live hover
...sing the following jquery code to show a contextual delete button only for table rows we are hovering with our mouse. This works but not for rows that have been added with js/ajax on the fly...
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How to reset db in Django? I get a command 'reset' not found error
...I needed not just to flush the values in the database, but to recreate the tables properly. I'm not using migrations yet (early days) so I really needed to drop all the tables.
Two ways I've found to drop all tables, both require something other than core django.
If you're on Heroku, drop all t...
What is the purpose of Order By 1 in SQL select statement?
...relation names are allowed in the OREDER BY clause because, in theory, the table correlation names are out of scope i.e. should be ORDER BY PAYMENT_DATE;. Of course, not all SQL implementations conform to Standards.
– onedaywhen
Aug 10 '10 at 7:17
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Oracle Differences between NVL and Coalesce
...n search contains comparison of nvl result with an indexed column.
create table tt(a, b) as
select level, mod(level,10)
from dual
connect by level<=1e4;
alter table tt add constraint ix_tt_a primary key(a);
create index ix_tt_b on tt(b);
explain plan for
select * from tt
where a=nvl(:1,a)
an...
Difference between @OneToMany and @ElementCollection?
...ring> strings;
Simpler, isn't it? Note that you can still control the table and column names using @CollectionTable annotation.
See also:
Java Persistence/ElementCollection
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Error 1046 No database Selected, how to resolve?
...ell MySQL which database to use:
USE database_name;
before you create a table.
In case the database does not exist, you need to create it as:
CREATE DATABASE database_name;
followed by:
USE database_name;
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Checking if a SQL Server login already exists
...ction. Attacker can pass a @loginName like x] with password ''y'';\r\ndrop table foo;\r\n
– Remus Rusanu
Sep 4 '09 at 14:47
2
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PostgreSQL Crosstab Query
... create crosstab queries in PostgreSQL?
For example I have the following table:
6 Answers
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