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What is “the inverse side of the association” in a bidirectional JPA OneToMany/ManyToOne association
... the object, in this case the customer. The customer has no columns in the table to store the orders, so you must tell it where in the order table it can save this data (which happens via mappedBy).
Another common example are trees with nodes which can be both parents and children. In this case, th...
Position of least significant bit that is set
...how to squeeze some cycles out of it?" makes such an answer perfectly acceptable!
– Mehrdad Afshari
Apr 16 '09 at 17:08
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What is the dual table in Oracle?
I've heard people referring to this table and was not sure what it was about.
14 Answers
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Using R to download zipped data file, extract, and import data
...oad.file("http://www.newcl.org/data/zipfiles/a1.zip",temp)
data <- read.table(unz(temp, "a1.dat"))
unlink(temp)
Compressed (.z) or gzipped (.gz) or bzip2ed (.bz2) files are just the file and those you can read directly from a connection. So get the data provider to use that instead :)
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MySQL Cannot Add Foreign Key Constraint
... as a project requirement and it worked the first time or two on different tables, but I have two tables on which I get an error when trying to add the Foreign Key Constraints.
The error message that I get is:
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Difference between EXISTS and IN in SQL?
... as a way to avoid counting:
--this statement needs to check the entire table
select count(*) from [table] where ...
--this statement is true as soon as one match is found
exists ( select * from [table] where ... )
This is most useful where you have if conditional statements, as exists can be ...
Table Naming Dilemma: Singular vs. Plural Names [closed]
Academia has it that table names should be the singular of the entity that they store attributes of.
41 Answers
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Delete/Reset all entries in Core Data?
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You can delete the SQLite file - but I choose to do it by purging the tables individually with a functions:
- (void) deleteAllObjects: (NSString *) entityDescription {
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription enti...
How do I find a default constraint using INFORMATION_SCHEMA?
...t if a given default constraint exists. I don't want to use the sysobjects table, but the more standard INFORMATION_SCHEMA.
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Tools to generate database tables diagram with Postgresql? [closed]
Are there any free tools to generate tables diagrams with Postgresql?
7 Answers
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