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Postgresql: Conditionally unique constraint
... a constraint which enforces uniqueness on a column only in a portion of a table.
2 Answers
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MongoDB Show all contents from all collections
...of your database.
db.stats()
step 5: listing out all the collections(tables).
show collections
step 6:print the data from a particular collection.
db.'collection_name'.find().pretty()
share
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SQL WHERE condition is not equal to?
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You can do like this
DELETE FROM table WHERE id NOT IN ( 2 )
OR
DELETE FROM table WHERE id <> 2
As @Frank Schmitt noted, you might want to be careful about the NULL values too. If you want to delete everything which is not 2(including the NULLs...
Group by month and year in MySQL
Given a table with a timestamp on each row, how would you format the query to fit into this specific json object format.
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How to stop text from taking up more than 1 line?
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Note: this only works on block elements. If you need to do this to table cells (for example) you need to put a div inside the table cell as table cells have display table-cell not block.
As of CSS3, this is supported for table cells as well.
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Why does my application spend 24% of its life doing a null check?
... other. With the GC heap compacting algorithm otherwise having an unpredictable affect on that. Best to not let me guess at this, measure so you know a fact.
– Hans Passant
May 15 '13 at 11:21
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SQL Server Profiler - How to filter trace to only display events from one database?
...lumn and find out the correct values to enter by querying the sysdatabases table in the master database
– Jim Birchall
Nov 10 '08 at 8:39
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Why does the order in which libraries are linked sometimes cause errors in GCC?
...linker will not link to libraries that are not actually needed by the executable (and it detects this from left to right). My recent archlinux distribution doesn't use this flag by default, so it didn't give an error for not following the correct order.
It is not correct to omit the dependency of b...
The case against checked exceptions
...with it.
This would be clearer with a counter-case. Imagine I'm writing a table API. I have the table model somewhere with an API including this method:
public RowData getRowData(int row)
Now as an API programmer I know there will be cases where some client passes in a negative value for the ro...
What is the difference between Non-Repeatable Read and Phantom Read?
What is the difference between non-repeatable read and phantom read?
9 Answers
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