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What is a good Hash Function?
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For doing "normal" hash table lookups on basically any kind of data - this one by Paul Hsieh is the best I've ever used.
http://www.azillionmonkeys.com/qed/hash.html
If you care about cryptographically secure or anything else more advanced, then Y...
ALTER TABLE to add a composite primary key
I have a table called provider . I have three columns called person , place , thing . There can be duplicate persons, duplicate places, and duplicate things, but there can never be a dupicate person-place-thing combination.
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Python Pandas merge only certain columns
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This is to merge selected columns from two tables.
If table_1 contains t1_a,t1_b,t1_c..,id,..t1_z columns,
and table_2 contains t2_a, t2_b, t2_c..., id,..t2_z columns,
and only t1_a, id, t2_a are required in the final table, then
mergedCSV = table_1[['t1_a','id']].m...
Django migration strategy for renaming a model and relationship fields
...different name, and the migration it creates will lose any data in the old table." Django 2.1 Docs For me, it was sufficient to create an empty migration, add the model renames to it, then run makemigrations as usual.
– hlongmore
Jan 15 '19 at 9:05
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How to declare a variable in a PostgreSQL query
... work as a variable, or even tuple of variables. It allows you to return a table of temporary values.
WITH master_user AS (
SELECT
login,
registration_date
FROM users
WHERE ...
)
SELECT *
FROM users
WHERE master_login = (SELECT login
FROM master_user)...
I want to copy table contained from one database and insert onto another database table
I want to copy a table's schema as well as the data within that table to another database table in another database on a live server. How could I do this?
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Why does Java switch on contiguous ints appear to run faster with added cases?
...ed to sparse), the generated bytecode for your various tests uses a switch table (bytecode instruction tableswitch).
However, once the JIT starts its job and compiles the bytecode into assembly, the tableswitch instruction does not always result in an array of pointers: sometimes the switch table i...
How to change the default collation of a table?
creates a table with the default collation latin1_general_ci ;
4 Answers
4
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Return a value if no rows are found in Microsoft tSQL
...ut instead of returning a 1, how can I get it to return the value from the table?
– Michael
Aug 10 '16 at 13:34
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show 3 more comments
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How to remove an element slowly with jQuery?
...otstrap.min.css" rel="stylesheet"/>
</head>
<body>
<table class="table table-striped table-bordered table-hover">
<thead>
<tr>
<th>id</th>
<th>firstname</th>
<th>lastname</th>
<th&g...