horizantal sharding exampl

[kampy]

Hi all,

I have requirement where i need to get data from 3 databases and integrate all the data. while searching i found there is support in SQLAlchemy by using horizantal sharding, but i didnt get any correct procedural way to do it. if anyone had done these kind of requirement please help me out in getting these things.

Thanks in Advance

[Michael Bayer]

when you say "get data from 3 databases" it sounds like each of these databases has a different set of tables within them.  this is called vertical partitioning.   horizontal partitioning is when each of the three databases contain identical schemas, each storing a subset of the data for those tables.

if you're vertically partitioning, the Session will switch among different databases based on the tables you ask for.   A brief description of that is here: http://docs.sqlalchemy.org/en/latest/orm/session.html#simple-vertical-partitioning.   Later on in that section is a description of horizontal partitioning, which is a more involved technique.

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[narasimha swamy]

hi mike ,
all the 3 databases have same tables but may have different data. i need to get all the data from 3 databases.

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Thanks & Regards,
 Narasimha
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[Michael Bayer]

great, so try digging into the horizontal sharding example, then, or alternatively just use three different Session objects (the latter is easier, if your sharding scheme is simple).