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Ways to implement data versioning in MongoDB
...t contain a dictionary of time-stamped diffs. Something like this:
{
_id : "id of address book record",
changes : {
1234567 : { "city" : "Omaha", "state" : "Nebraska" },
1234568 : { "city" : "Kansas City", "state" : "Missouri" }
}
}
To make ...
how to override action bar back button in android?
...tivity back button in action bar, not in hard key back button. I have overriden the onBackPressed() method. It works with my emulator back button, but not with action bar back button.
...
Select datatype of the field in postgres
... ?
For example
I have the following table,
student_details (
stu_id integer,
stu_name varchar(30 ),
joined_date timestamp
);
...
How do I find duplicate values in a table in Oracle?
...XISTS (
SELECT 1 FROM TABLE
WHERE COLUMN_NAME = A.COLUMN_NAME
AND ROWID < A.ROWID
)
Works fine (quick enough) when there is index on column_name. And it's better way to delete or update duplicate rows.
share
...
findViewById in Fragment
... which I have created in the XML for the Fragment. However, the findViewById method only works if I extend an Activity class. Is there anyway of which I can use it in Fragment as well?
...
How do I get textual contents from BLOB in Oracle SQL
I am trying to see from an SQL console what is inside an Oracle BLOB.
11 Answers
11
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MongoDB atomic “findOrCreate”: findOne, insert if nonexistent, but do not update
as the title says, I want to perform a find (one) for a document, by _id, and if doesn't exist, have it created, then whether it was found or was created, have it returned in the callback.
...
Specify an SSH key for git push for a given domain
...olve this using ~/.ssh/config , because the user name and server name are identical in both cases. As I mostly use my own private key, I have that defined in ~/.ssh/config for git@git.company.com . Does anyone know of a way to override the key that is used for a single git invocation?
...
What is the difference between JOIN and UNION?
...er, then the data from the first table is shown in one set of column alongside the second table’s column in the same row.
Unions combine data into new rows. If two tables are “unioned” together, then the data from the first table is in one set of rows, and the data from the second table in a...
rails 3 validation on uniqueness on multiple attributes
...
In Rails 2, I would have written:
validates_uniqueness_of :zipcode, :scope => :recorded_at
In Rails 3:
validates :zipcode, :uniqueness => {:scope => :recorded_at}
For multiple attributes:
validates :zipcode, :uniqueness => {:scope => [:recor...