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Using C++ library in C code
... layer in C++ that declares functions with extern "C":
extern "C" int foo(char *bar)
{
return realFoo(std::string(bar));
}
Then, you will call foo() from your C module, which will pass the call on to the realFoo() function which is implemented in C++.
If you need to expose a full C++ class w...
Can PHP PDO Statements accept the table or column name as parameter?
... case 1:
$tbl = 'users';
break;
}
$sql = "SELECT * FROM $tbl";
}
By leaving no default case or using a default case that returns an error message you ensure that only values that you want used get used.
...
How to 'insert if not exists' in MySQL?
...
Solution:
INSERT INTO `table` (`value1`, `value2`)
SELECT 'stuff for value1', 'stuff for value2' FROM DUAL
WHERE NOT EXISTS (SELECT * FROM `table`
WHERE `value1`='stuff for value1' AND `value2`='stuff for value2' LIMIT 1)
Explanation:
The innermost query
SELECT *...
How to find all tables that have foreign keys that reference particular table.column and have values
...
Here you go:
USE information_schema;
SELECT *
FROM
KEY_COLUMN_USAGE
WHERE
REFERENCED_TABLE_NAME = 'X'
AND REFERENCED_COLUMN_NAME = 'X_id';
If you have multiple databases with similar tables/column names you may also wish to limit your query to a particul...
String is immutable. What exactly is the meaning? [duplicate]
...
A string is a char[] containing a series of UTF-16 code units, an int offset into that array, and an int length.
For example.
String s
It creates space for a string reference. Assigning copies references around but does not modify the...
Adding a library/JAR to an Eclipse Android project
...w application project.
When you are creating the library project, you can select any application name, package, and set other fields as needed, as shown in figure 1.
Next, set the project's properties to indicate that it is a library project:
In the Package Explorer, right-click the library proje...
Postgresql aggregate array
...
Use array_agg: http://www.sqlfiddle.com/#!1/5099e/1
SELECT s.name, array_agg(g.Mark) as marks
FROM student s
LEFT JOIN Grade g ON g.Student_id = s.Id
GROUP BY s.Id
By the way, if you are using Postgres 9.1, you don't need to repeat the columns on SELECT to GROUP BY,...
SQL Server equivalent to Oracle's CREATE OR REPLACE VIEW
...y create or replace views or stored procedures as follows.
IF NOT EXISTS (SELECT * FROM sys.views WHERE object_id = OBJECT_ID(N'[dbo].[vw_myView]'))
EXEC sp_executesql N'CREATE VIEW [dbo].[vw_myView] AS SELECT ''This is a code stub which will be replaced by an Alter Statement'' as [code_stub]'
...
OR is not supported with CASE Statement in SQL Server
...sions anywhere in the SQL queries. CASE expressions can be used within the SELECT statement, WHERE clauses, Order by clause, HAVING clauses, Insert, UPDATE and DELETE statements.
A CASE expression has the following two formats:
Simple CASE expression
CASE expression
WHEN expression1 THEN Result1...
Are there any disadvantages to always using nvarchar(MAX)?
...E @SomeString NVARCHAR(10),
@StartTime DATETIME;
--=====
SELECT @startTime = GETDATE();
SELECT TOP 1000000
@SomeString = 'ABC'
FROM master.sys.all_columns ac1,
master.sys.all_columns ac2;
SELECT testTime='10', Duration = DATEDIFF(ms,@StartTime,GETDATE());
GO
--...