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Oracle Differences between NVL and Coalesce
...n search contains comparison of nvl result with an indexed column.
create table tt(a, b) as
select level, mod(level,10)
from dual
connect by level<=1e4;
alter table tt add constraint ix_tt_a primary key(a);
create index ix_tt_b on tt(b);
explain plan for
select * from tt
where a=nvl(:1,a)
an...
Algorithm to find top 10 search terms
...ue ID for each. This whole set of data can be loaded into memory as a hash table, consuming roughly 300MB memory. (We have implemented our own hash table. The Java's implementation takes huge memory overhead)
Each phrase then can be identified as an array of integers.
This is important, because s...
Request is not available in this context
...ot leave the fields null. (In my case, don't write a record to one logging table, but it would help if there were a good way to determine whether or not is available.)
– Zarepheth
Sep 11 '14 at 21:47
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How to set a Django model field's default value to a function call / callable (e.g., a date relative
...ow_add=True in the constructor, the datetime referenced by my_date is "immutable" (only set once when the row is inserted to the table).
With auto_now=True, however, the datetime value will be updated every time the object is saved.
This was definitely a gotcha for me at one point. For reference, ...
How should I store GUID in MySQL tables?
...the intention of representing said value with a value mapped from a lookup table (in most cases now, UTF8). A BINARY field expects the same kind of value without any intention of representing said data from a lookup table. I used CHAR(16) back in the 4.x days because back then MySQL wasn't as good a...
How do I use LINQ Contains(string[]) instead of Contains(string)
...ids = arrayofuids.Select(id => int.Parse(id)).ToList();
var selected = table.Where(t => uids.Contains(t.uid));
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MySQL - length() vs char_length()
... 2 characters, even though like all combining marks it can — if a suitable font is available — be rendered as a single glyph. UTF-16LE can still have a 4-byte character though thanks to the surrogates.
– bobince
Nov 14 '09 at 22:05
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Difference between Divide and Conquer Algo and Dynamic Programming
...blem is solved only once and the result of each sub-problem is stored in a table ( generally implemented as an array or a hash table) for future references. These sub-solutions may be used to obtain the original solution and the technique of storing the sub-problem solutions is known as memoization....
How to calculate percentage with a SQL statement
I have a SQL Server table that contains users & their grades. For simplicity's sake, lets just say there are 2 columns - name & grade . So a typical row would be Name: "John Doe", Grade:"A".
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Run PostgreSQL queries from the command line
I inserted a data into a table....I wanna see now whole table with rows and columns and data. How I can display it through command?
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