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Filter by property
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Nope. Django filters operate at the database level, generating SQL. To filter based on Python properties, you have to load the object into Python to evaluate the property--and at that point, you've already done all the work to load it.
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What is the difference between map and flatMap and a good use case for each?
...ocessing the data.
Below is the sample data file.
hadoop is fast
hive is sql on hdfs
spark is superfast
spark is awesome
The above file will be parsed using map and flatMap.
Using map
>>> wc = data.map(lambda line:line.split(" "));
>>> wc.collect()
[u'hadoop is fast', u'hive ...
What are OLTP and OLAP. What is the difference between them?
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"When in doubt, I just use SQL." - SQL is a language and this doesn't answer the question. There's all kinds of data mgmt systems that know how interpret SQL and to translate it for working with all kinds of datasources behind the hood. One can make sq...
PostgreSQL naming conventions
Where can I find a detailed manual about PostgreSQL naming conventions? (table names vs. camel case, sequences, primary keys, constraints, indexes, etc...)
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SQL query to get all values a enum can have
Postgresql got enum support some time ago.
4 Answers
4
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PostgreSQL delete all content
Hello I want to delete all data in my postgresql tables, but not the table itself.
How could I do this?
3 Answers
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Mocking python function based on input arguments
...d from a database and we would like to test this module by mocking pd.read_sql_table method (which takes table_name as argument).
What you can do is to create (inside your test) a db_mock method that returns different objects depending on the argument provided:
def db_mock(**kwargs):
if kwargs...
MySQL stored procedure vs function, which would I use when?
I'm looking at MySQL stored procedures and function. What is the real difference?
5 Answers
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How to establish a connection pool in JDBC?
...ource cpds = new ComboPooledDataSource();
cpds.setDriverClass( "org.postgresql.Driver" ); //loads the jdbc driver
cpds.setJdbcUrl( "jdbc:postgresql://localhost/testdb" );
cpds.setUser("swaldman");
cpds.setPassword("test-password");
// the settings below are optional -- c3p0 can work with defaults
c...
PostgreSQL Crosstab Query
Does any one know how to create crosstab queries in PostgreSQL?
For example I have the following table:
6 Answers
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