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11h
comment Can any one Explain me What is the Use of Cascading Replication in Postgresql?
If you do a switchover from master to slave1, you still have a spare slave if the now active master also fails. Otherwise you'd be running with no failover computer at all.
11h
comment How can I insert rows into a table from a select query that brings duplicate entries?
The reason the unnecessary parentheses caused an error is that in Postgres (a,b) is actually a single column, whereas the expression a,b are two columns (and the error message should have contained a hint for that) For details see here: stackoverflow.com/q/27083330/330315
11h
revised How can I insert rows into a table from a select query that brings duplicate entries?
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20h
comment Duplicate values
Which DBMS are you using? Postgres? Oracle?
20h
revised Duplicate values
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1d
comment Increase performance WITHOUT adding indexes
I wouldn't call statements "which are only performed every few seconds" rare. The are executed often enough to warrant an index. I have never seen a DBMS where adding an index would make the statement slower because parsing (the step where the best index is searched for) became an issue. When it comes to performance don't just assume things. Test them. Your concern about the DML is a valid one though, but I have seen only a few systems where adding an index really made the DML so bad that it had to be removed. But again: you have to test this.
1d
revised Increase performance WITHOUT adding indexes
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1d
comment How long to learn PostgreSQL?
"Entirely removing Postgres can be a bit tricky" - to "play" around I usually only unzip the archives (e.g. the zip on Windows) and run initdb manually. To "throw away" such an installation, all I need to do is to delete the directory where I unzipped the archive.
1d
revised how to define trigger scope variable
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1d
comment Error on DDL statement never invokes CATCH
"I understand that DDL statements are implicit COMMIT" - I think you are confusing Oracle (or MySQL) and SQL Server.
1d
comment How long to learn PostgreSQL?
Make sure you take the time to go through the manual, at least the chapter "SQL Language": postgresql.org/docs/current/static/sql.html
2d
comment How to restrict access to current user record and its rights in postgres
"Is it possible and reasonable to create plpgsql methods for those operations" - yes, that is possible and probably a bit safer than using a view.
2d
answered SQL MAX function
Nov
22
revised Time series and gap filling
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Nov
22
revised check numeric column for empty cells
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Nov
22
answered check numeric column for empty cells
Nov
22
comment how to select from two tables
You are looking for a JOIN
Nov
22
revised how to select from two tables
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Nov
22
revised How do I show all records related to a user?
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Nov
22
revised What's wrong with my SQL statement?
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