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Oracle: how to UPSERT (update or insert into a table?)
...before the insert regardless of how many concurrent calls are made to same SQL code. Worst case, you may get lots of contention and Oracle will take much longer to reach a final state.
– Neo
Nov 6 '12 at 13:23
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How to split a string literal across multiple lines in C / Objective-C?
I have a pretty long sqlite query:
9 Answers
9
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Is there any boolean type in Oracle databases?
... any Boolean type in Oracle databases, similar to the BIT datatype in Ms SQL Server?
11 Answers
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What is causing this ActiveRecord::ReadOnlyRecord error?
... you use this option, saving the same
record will now fail. Use find_by_sql
to work around.
Using find_by_sql is not really an alternative as it returns raw row/column data, not ActiveRecords. You have two options:
Force the instance variable @readonly to false in the record (hack)
Use :in...
Postgis installation: type “geometry” does not exist
...eate table with Postgis. I do it by this page . But when I import postgis.sql file, I get a lot of errors:
10 Answers
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Foreign key constraint may cause cycles or multiple cascade paths?
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SQL Server does simple counting of cascade paths and, rather than trying to work out whether any cycles actually exist, it assumes the worst and refuses to create the referential actions (CASCADE): you can and should still cr...
Postgres: INSERT if does not exist already
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@TusharJain prior to PostgreSQL 9.5 you can do an "old fashioned" UPSERT (with CTE) but you may experience problems with race conditions and it will not be performant as 9.5 style. There is a good detail about upsert on this blog (in the updated area at...
MySQL ON vs USING?
In a MySQL JOIN , what is the difference between ON and USING() ? As far as I can tell, USING() is just more convenient syntax, whereas ON allows a little more flexibility when the column names are not identical. However, that difference is so minor, you'd think they'd just do away with USI...
Which are more performant, CTE or temporary tables?
...y to other constructs that can also be used as inline table expressions in SQL Server. Derived tables, Views, and inline table valued functions. Note that whilst BOL says that a CTE "can be thought of as temporary result set" this is a purely logical description. More often than not it is not materl...
SQL Server indexes - ascending or descending, what difference does it make?
When you create an index on a column or number of columns in MS SQL Server (I'm using version 2005), you can specify that the index on each column be either ascending or descending. I'm having a hard time understanding why this choice is even here. Using binary sort techniques, wouldn't a lookup be ...