i know this would be probably too much to ask for . i am sorry. and i would really appreciate if someone can guide me in the right direction.
i have made the sales invoice posting form.
the fields are:-
customer id, segment id, date of invoice, invoice no(streamed from mysql max value), items,uom's prices,quantities.
since the no of items is variable. as in the no of rows changes so i have made it dynamic as per user's requirement.
i am able to display this data on the next page.
now when i have say 5 itemcodes, their prices and quantities, i want to compare all of these with their corresponding mysql values. for ex. for quantities, i would like to compare the quantities avl in mysql and only then proceed with posting, same is the case with prices. i want to compare the prices with the selling prices listed for those particular items.
i also need help with how to post these arrays to the mysql and then check what all has been posted correctly.
i would greatly appreciate any information,ideas,links, etc. where i can learn or may be if someone can post up a sample code or something.
thanks again.keep smiling :-)
From what I understand, you are trying to INSERT invoice data after validating from MySQL. A generic answer would:
Receive the data at the server.
Do the logical validation.
Use SELECT to get respective values from the database
Compare those values with the received one
Execute an INSERT query if successful.
There are many ways to solve your problem of posting arrays in MySQL, in certain cases, I send client side arrays as CSV strings and use something like PHP-explode("," $str) and then insert individual values, however it will differ based on your data-formatting and table design.
Related
I'm building an eCommerce site with Codeigniter which will allow users to register, buy products and then track the orders.
I'm using the following in several places around the site, mainly when a user is submitting an order:
$this->db->insert_id();
Basically when a user submits an order, it will add the order to one table, and then, within the same segment of code (immediately after the insert query), add each order item to another table using the ID created when the order is inserted into the first table.
My question is: Out of the following, what does $this->db->insert_id(); do:
1) Does it get the ID that has just been inserted in (and only from) insert query just run?
2) Does it get the last inserted ID from the latest entry in the database regardless of what query its come from?
Basically I'm trying to avoid orders being mixed up, say for example if several customers were submitting orders at the same time, I don't want one customer's order items to be added to the incorrect order.
I think the answer is 1, and that there's no problem, but I wanted to be sure.
Thanks!
It gets the ID that last inserted by the last query. So what you said in #1
Just a suggestion - but another way to do this is to generate a random string - and use that to associate the cart items and order together - instead of by order id. you would still use the order id as the "order number".
this gives you the option of generating that random string when the shopping session first begins and using it to tie the cart items, shipping, billing etc together as the purchase is proceeding. so in that way you are starting the order immediately, but you haven't had to commit a space in the final order table until the transaction verifies.
Your question exposes a potential bug in the codeigniter environment. If two inserts are done in rapid succession, how do you have confidence that the ID returned from insert_id is the proper ID?
Codeigniter documentation does not answer this question
http://ellislab.com/codeigniter/user-guide/database/helpers.html
A relevant blog entry from ellis lab does not resolve the question. It concludes that the appropriate resolution is to take your chances.
http://ellislab.com/forums/viewthread/63052/
If this function is a wrapper function for mysqli_insert_id, the documentation at php.net is unclarified.
http://www.php.net/manual/en/mysqli.insert-id.php
It states the ID is from "the last query". It does not say whose last query.
Two successive inserts, and the return of a wrong ID will compromise the integrity of your data. The way to be sure is lock the database.
$this->db->query('LOCK TABLE (your table name) WRITE');
$this->db->insert('(your table name');
$int_id = $this->db->insert_id();
$this->db->query('UNLOCK TABLES');
This has a negative impact on execution time, but depending on your server's capacity is likely preferable to data corruption.
First of, I'm pretty new to this site and coding in general so please explain in simple terms as I'm still learning! Thanks
Ok, so I've got a database of results. These are 1-6 ratings. I've already created the ability to retrieve certain results (user, group, all).
But now I'm wanting to alongside retrieving the group and all results to display at the top of the results a mean for each question.
So to start I'm wanting something like this I believe.
SELECT sum(r1), sum(r2), sum(r3) so on,
FROM table
This is where I get confused.
I think I'd need a variable to contain these and then another that counts the amount of entries to divide the total of r1 hence the mean.
Any ideas?..
To calculate a mean, use the AVG function, e.g.
SELECT AVG(r1), AVG(r2)
FROM table
See the MySQL docs.
This one might be a bit complicated. I searched for similar questions and found nothing that seemed relevant.
Let me start by establishing my database structure.
I have several tables, but the relevant ones are as follows:
Right now I have the decklist stored as a string of cardid delimited by a comma. I realize this is inefficient and when I get around to improving my code I will make a new table tcg_card_in_deck that has relationid, cardid, deckid. For now my code assumes a decklist string.
I'm building a function to allow purchases of a deck. In order to give them the actual cards, I have the following query (generated with the PHP it will actually be about 50 entries):
$db->query_write("INSERT INTO
`tcg_card`
(masterid, userid, foil)
VALUES
('159', '15', '0'),
('209', '15', '0'),
('209', '15', '0'),
('318', '15', '0')");
This part is easy. My issue now is making sure the cards that have just been added can have their ids grabbed and put together in an array (to enter in as a string currently, and as entries into the separate table once the code is updated). If it was one entry I could use LAST_INSERT_ID(). If I did 50 separate insert queries I could grab the id on each iteration and add them into the array. But because it's all done with one query, I don't know how to effectively find the correct cards to put in the decklist. I suppose I could add a dateline field to the cards table to specify date acquired, but that seems sloppy and it may produce flawed results if a user gets cards from a trade or a booster pack in a similar timeframe.
Any advice would be appreciated!
Change tcg_card by removing cardid, and make masterid and userid a compound key. Then, add a row called quantity. Since you cannot distinguish between two copies of a card in any meaningful way (except for being foils, which you could handle with this schema), there is no need for every card to get its own ID.
Presumably you aren't entering new tcg_master rows dynamically, so you don't have to worry about pulling their IDs back out.
Reading comments on this question I thought of a very simple and easy solution:
Get all inserted IDs when inserting multiple rows using a single query
I already track booster pack purchases with a table tcg_history. This table can also track other types of purchases, such as a starter deck.
I simply need to add a field on the tcg_card table that references a tcg_history.recordid, then I will be able to select all cards that are from that purchase.
For a new version of a website, I am making a "Top User" section on the homepage. This allows people to vote for the user on a bunch of different categories. All this information is stored in a MySQL database in two main tables. One table has the information(id*autogenerated*, Username, Date added, etc.) and the other has the rates (id*autogenerated*, linkID, rowAvg, avg, avg2, etc.). The linkID from the rate table corresponds to the id from the information table. How the query works is it queries through the rate_table, orders it by highest averages then selects the first 10 results. Then using the linkID of that row, I select the actual information for that user from the info_table. This is fine and dandy as long as each user only has 1 rate. What happens when a user has 2 or more rates, and both of the rates are positive, is the query selects both of those and pulls the information for each of the 2 rows which is then displayed as two different users even though it is the same person. How can I make the rate_table query know when there are multiple rates for the same linkID and average them together instead of showing them as two different people. I was thinking of inserting each linkID into an array, then for each subsequently selected row, check if that linkID is already in the array. If not, insert it, if it is, then average them together and store it in the array and use the array to populate the table on the homepage. I feel like I am overthinking this. Sorry if this is a little confusing. If you need more information, let me know.
P.S. I'm still learning my way around MySQL queries so I apologize if I am going about this the completely wrong way and you spent the last few minutes trying to understand what I was saying :P
P.P.S. I know I shouldn't be using MySQL_Query anymore, and should be doing prepared statements. I want to master MySQL queries because that is what FMDB databases for iOS use then I will move onto learning prepared statements.
Take a look at some of the MySQL Aggregate Functions.
AVG() may be what you're looking for. The average of one result is just that result, so that should still work. Use the GROUP BY clause on the column that should be unique in order to run the aggregate calculation on the grouped rows.
I have a drupal site, and am trying to use php to grab some data from my database. What I need to do is to display, in a user's profile, how many times they were the first person to review a venue (exactly like Yelp's "First" tally). I'm looking at two options, and trying to decide which is the better way to approach it.
First Option: The first time a venue is reviewed, save the value of the reviewer's user ID into a table in the database. This table will be dedicated to storing the UID of the first user to review each venue. Then, use a simple query to display a count in the user's profile of the number of times their UID appears in this table.
Second Option: Use a set of several more complex queries to display the count in the user's profile, without storing any extra data in the database. This will rely on several queries which will have to do something along the lines of:
Find the ID for each review the user has created
Check the ID of the venue contained in each review
First review for each venue based on the venue ID stored in the review
Get the User ID of the author for the first review
Check which, if any, of these Author UIDs match the current user's UID
I'm assuming that this would involve creating an array of the IDs in step one, and then somehow executing each step for each item in the array. There would also be 3 or 4 different tables involved in the query.
I'm relatively new to writing SQL queries, so I'm wondering if it would be better to perform the set of potentially longer queries, or to take the small database hit and use a much much smaller count query instead. Is there any way to compare the advantages of either, or is it like comparing apples and oranges?
The volume of extra data stored will be negligible; the simplification to the processing will be significant. The data won't change (the first person to review a venue won't change), so there is a negligible update burden. Go with the extra data and simpler query.