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What is the difference between a database and a data warehouse?
... as Data Warehousing. This records the data from the user for history.
The tables and joins are complex since they are normalized (for RDMS). This is done to reduce redundant data and to save storage space.
Entity – Relational modeling techniques are used for RDMS database design.
Optimized for wr...
SQL: IF clause within WHERE clause
...tside the SELECT
IF (IsNumeric(@OrderNumber)) = 1
BEGIN
SELECT * FROM Table
WHERE @OrderNumber = OrderNumber
END ELSE BEGIN
SELECT * FROM Table
WHERE OrderNumber LIKE '%' + @OrderNumber
END
3) Using a long string, compose your SQL statement conditionally, and then use EXEC
The 3r...
@Override is not allowed when implementing interface method
....
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How to make a floated div 100% height of its parent?
...ion, and even if you have several floated child elements, it seems an acceptable drawback to style their offset absolutely positioned. +1
– kontur
Jul 7 '14 at 11:26
...
How does the socket API accept() function work?
...g on the Server IP maintains a database (meaning I don't care what kind of table/list/tree/array/magic data structure it uses) of active sockets and listens on the Server Port. When it receives a message (via the server's TCP/IP stack), it checks the Client IP and Port against the database. If the...
What is lazy loading in Hibernate?
...e child when parent is loaded from the database.
Example :
If you have a TABLE ? EMPLOYEE mapped to Employee object and contains set of Address objects.
Parent Class : Employee class,
Child class : Address Class
public class Employee {
private Set address = new HashSet(); // contains set of ch...
What does SQL clause “GROUP BY 1” mean?
...d name, you may also group by ordinal, or position of the field within the table. 1 corresponds to the first field (regardless of name), 2 is the second, and so on.
This is generally ill-advised if you're grouping on something specific, since the table/view structure may change. Additionally, it ma...
Swift native base class or NSObject
...r by using the '@objc' decoration. Otherwise it will follow a static- and vtable-dispatch style, like C++.
6 Answers
...
Comparing date ranges
... |-----| equal start with end of comparison period
If your table has columns called range_end and range_start, here's some simple SQL to retrieve all the matching rows:
SELECT *
FROM periods
WHERE NOT (range_start > @check_period_end
OR range_end < @check_period_s...
How to extract year and month from date in PostgreSQL without using to_char() function?
I want to select sql:
SELECT "year-month" from table group by "year-month" AND order by date , where
year-month - format for date "1978-01","1923-12".
select to_char of couse work , but not "right" order:
...