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Add unique constraint to combination of two columns
I have a table and, somehow, the same person got into my Person table twice. Right now, the primary key is just an autonumber but there are two other fields that exist that I want to force to be unique.
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How to implement a Map with multiple keys? [duplicate]
...nother solution is to use Google's Guava
import com.google.common.collect.Table;
import com.google.common.collect.HashBasedTable;
Table<String, String, Integer> table = HashBasedTable.create();
The usage is really simple:
String row = "a";
String column = "b";
int value = 1;
if (!table.c...
Dynamic Sorting within SQL Stored Procedures
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This approach keeps the sortable columns from being duplicated twice in the order by, and is a little more readable IMO:
SELECT
s.*
FROM
(SELECT
CASE @SortCol1
WHEN 'Foo' THEN t.Foo
WHEN 'Bar' THEN t.Bar
ELSE null
END as ...
What is dynamic programming? [closed]
...problem.
With dynamic programming, you store your results in some sort of table generally. When you need the answer to a problem, you reference the table and see if you already know what it is. If not, you use the data in your table to give yourself a stepping stone towards the answer.
The Cormen ...
“’” showing on page instead of “ ' ”
...h is being decoded as CP-1252 instead of UTF-8. If you check the encodings table, then you see that this character is in UTF-8 composed of bytes 0xE2, 0x80 and 0x99. If you check the CP-1252 code page layout, then you'll see that each of those bytes stand for the individual characters â, € and ...
Restrict varchar() column to specific values?
...t on that column which would restrict values? Something like:
CREATE TABLE SomeTable
(
Id int NOT NULL,
Frequency varchar(200),
CONSTRAINT chk_Frequency CHECK (Frequency IN ('Daily', 'Weekly', 'Monthly', 'Yearly'))
)
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Most efficient way to remove special characters from string
...ms.
The price to pay is, of course, the initialization of the huge lookup table and keeping it in memory. Well, it's not that much data, but it's much for such a trivial function...
private static bool[] _lookup;
static Program() {
_lookup = new bool[65536];
for (char c = '0'; c <= '9'; ...
Entity Framework: One Database, Multiple DbContexts. Is this a bad idea? [closed]
...ngle context per app can be expensive if the application has many entities/tables. Thus depending on the schema, it might also make sense to have multiple contexts.
– DarthVader
May 13 '13 at 7:04
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How do I specify unique constraint for multiple columns in MySQL?
I have a table:
14 Answers
14
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Is there any advantage of using map over unordered_map in case of trivial keys?
...f course) when using unordered_map instead of map in a main entity look-up table.
On the other hand, I found it was much slower at repeatedly inserting and removing elements. It's great for a relatively static collection of elements, but if you're doing tons of insertions and deletions the hashing ...