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How to create a HashMap with two keys (Key-Pair, Value)?
...mply use:
Map<Key, V> map = //...
and:
map.get(new Key(2, 5));
Table from Guava
Table<Integer, Integer, V> table = HashBasedTable.create();
//...
table.get(2, 5);
Table uses map of maps underneath.
N dimensions
Notice that special Key class is the only approach that scales to...
MySQL selecting yesterday's date
... and
UNIX_TIMESTAMP(current_date)) as timesVisitedYesterday
FROM mytable
GROUP BY 1
For the curious, the reason that sum(condition) gives you the count of rows that satisfy the condition, which would otherwise require a cumbersome and wordy case statement, is that in mysql boolean values a...
Is there type Long in SQLite?
I want to create a table with the column type Long instead of Integer . Is it possible?
7 Answers
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Best way for a 'forgot password' implementation? [closed]
... username, because usernames are sometimes forgotten too.
The system has a table password_change_requests with the columns ID, Time and UserID. When the new user presses the button, a record is created in the table. The Time column contains the time when the user pressed the "Forgot Password" button...
Threads vs Processes in Linux
...of sharing, among which are:
CLONE_FILES: share the same file descriptor table (instead of creating a copy)
CLONE_PARENT: don't set up a parent-child relationship between the new task and the old (otherwise, child's getppid() = parent's getpid())
CLONE_VM: share the same memory space (instead of c...
Update all values of a column to lowercase
...v.mysql.com/doc/refman/5.0/en/string-functions.html#function_lower
UPDATE table_name SET tag = LOWER(tag)
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How do I generate random number for each row in a TSQL Select?
I need a different random number for each row in my table. The following seemingly obvious code uses the same random value for each row.
...
Repository Pattern Step by Step Explanation [closed]
...are persisted. All of the knowledge of persistence, including mapping from tables to objects, is safely contained in the repository.
Very often, you will find SQL queries scattered in the codebase and when you come to add a column to a table you have to search code files to try and find usages of a...
Read data from SqlDataReader
...se the first column you selected in your query or the firstt column on the table. I have a table with 3 columns in order: ID, Dir, Email. My command selects dir and email. Will reader.GetStrting(0) retrieve dir or ID? Are the indexes based off the table itself on SQL Server or off the query you ...
Create Pandas DataFrame from a string
...
FYI - pd.read_table() is an equivalent function, just slightly better nomenclature: df = pd.read_table(TESTDATA, sep=";").
– wkzhu
Dec 6 '17 at 23:17
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