How might I insert an array of data into a database table? - sql

Question

I am developing an attendance management program, used to maintain the absence record of a student. Users of this software will need to enter various dates, updated once in a month: for instance, a list of dates on which a student was absent for that particular month would be entered, and my program must then store them into a database with each date added as a new row in the appropriate table.
I have the dates stored using arrays internally, how might I transfer these into the database? How should I proceed?

Answer 1

You have not mentioned the database system being used, so my reply is general in nature. The usual way to do this is to run multiple insert statements one after another:
INSERT INTO Table1 (FirstColumn, SecondColumn)
VALUES ('a', 'b');
INSERT INTO Table1 (FirstColumn, SecondColumn)
VALUES ('c', 'd');
INSERT INTO Table1 (FirstColumn, SecondColumn)
VALUES ('e', 'f');
GO
The trick way to do this is to use the UNION ALL statement:
INSERT INTO Table1 (FirstColumn, SecondColumn)
SELECT 'a', 'b'
UNION ALL
SELECT 'c', 'd'
UNION ALL
SELECT 'e', 'f'
GO
Versions of SQL Server prior to 2008 support only these methods. But SQL 2008 and MySQL 3.22 and above support the Row construction method as well:
INSERT INTO Table1 (FirstColumn, SecondColumn)
VALUES ('a', 'b'),
VALUES ('c', 'd'),
VALUES ('e', 'f')
GO
Now you can use any of the above methods to iterate through your array and add individual attendance rows to the database.

Answer 2

foreach($arrayName as $arrayValue) {
// run your query here!
}
for example:
$myArray = array('apple','orange','grape');
foreach($myArray as $arrayFruit) {
$query = "INSERT INTO `Fruits` (`FruitName`) VALUES ('" . $arrayFruit . "')";
mysql_query($query, $connection);
}
does that makes sense / fit what you were thinking?

Answer 3

Do you want to store the dates seperately so you can juggle with them, query them, etc.?
Or do you just want to store the array as is?
If you want to store the dates separately you may want to create a table with an FK to students, a column for date and a column for the nature of the date, like absence, late, ...
Then you would indeed store the single dates into that table. If you must, by iterating but if you can with one of Cerbrus' solutions!. It is not recommended to have db-queries within loops.
If you just need to store that array somewhere, you can serialize it and store the serialized string in a text or varchar column.

Answer 4

What language and what type of database are you using? Is this a web application? A desktop application? We can't help you without more information.
Depending on your situation, any of the above solutions could work. Or you could even load all of the attendance records at once as a CSV or XML document. Perhaps a little more research on your part will help you ask a more useful question?

Answer 5

Iterate over the array and execute insert SQL for each date.