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How important is the order of columns in indexes?
...hat I am illustrating in a very simple way. This isn't very unique or even SQL specific; B-tree indexing is pretty common across so many things.
– Nick Craver♦
Aug 23 '16 at 10:11
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How to make connection to Postgres via Node.js
...se, so I installed postgres and started a server with initdb /usr/local/pgsql/data , then I started that instance with postgres -D /usr/local/pgsql/data now how can I interact with this through node? For example, what would the connectionstring be, or how am I able to find out what it is.
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How do you track record relations in NoSQL?
I am trying to figure out the equivalent of foreign keys and indexes in NoSQL KVP or Document databases. Since there are no pivotal tables (to add keys marking a relation between two objects) I am really stumped as to how you would be able to retrieve data in a way that would be useful for normal we...
ROW_NUMBER() in MySQL
Is there a nice way in MySQL to replicate the SQL Server function ROW_NUMBER() ?
24 Answers
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How do I reset a sequence in Oracle?
In PostgreSQL , I can do something like this:
18 Answers
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Checkout one file from Subversion
... cd /tmp
$ svn co --depth empty http://svn.your.company.ca/training/trunk/sql
Run svn up to update specified file:
$ svn up http://svn.your.company.ca/training/trunk/sql/showSID.sql
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Is there a good reason I see VARCHAR(255) used so often (as opposed to another length)?
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@CharlesBretana: By "fake UTF-8" I mean MySQL's "utf8" encoding, which as I mentioned reserves (and is limited to) 3 bytes per character. This isn't a very good version of UTF-8; if you want decent UTF-8 in MySQL, you have to use its "utf8mb4" encoding. But people ...
How to add column if not exists on PostgreSQL?
...executed as queries), it would be a recipe for disaster as it opens you to SQL injection attacks.
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mongoose vs mongodb (nodejs modules/extensions), which better? and why?
...you're looking for an object modeling (ODM, a counterpart to ORMs from the SQL world) tool to skip some lower level work, you want Mongoose.
If you want a driver, because you intend to break a lot of rules that an ODM might enforce, go with MongoDB. If you want a fast driver, and can live with some...
Expansion of variables inside single quotes in a command in Bash
...by concatenating variables. This is a bad idea similar to concatenation of SQL fragments (SQL injection!).
Usually it is possible to have placeholders in the command, and to supply the command together with variables so that the callee can receive them from the invocation arguments list.
For examp...