I'm designing an API to get data from the following scenario :
brands table :
+------------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+------------+--------------+------+-----+---------+----------------+
| id | bigint(20) | NO | PRI | NULL | auto_increment |
| name | varchar(255) | YES | | NULL | |
+------------+--------------+------+-----+---------+----------------+
items table :
+---------------------------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+---------------------------+--------------+------+-----+---------+----------------+
| id | bigint(20) | NO | PRI | NULL | auto_increment |
| category_id | bigint(20) | YES | MUL | NULL | |
| brand_id | bigint(20) | YES | | NULL | |
+---------------------------+--------------+------+-----+---------+----------------+
item_skus table :
+---------------------------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+---------------------------+--------------+------+-----+---------+----------------+
| id | bigint(20) | NO | PRI | NULL | auto_increment |
| item_id | bigint(20) | YES | MUL | NULL | |
| number_of_stock | int(11) | YES | | NULL | |
+---------------------------+--------------+------+-----+---------+----------------+
Item model association with ItemSku and Brand
belongs_to :brand
has_many :skus, class_name: 'ItemSku'
Simply i want the counts of stock available items and all items for each brand.
{
"brandCounts":[
{
"id":7006,
"name":"Brand 01",
"stockAvailableItemCount":50,
"allItemCount":60
},
{
"id":20197,
"name":"Brand 02"
"availableItemCount":150,
"allItemCount":660
}
]
}
Implementation :
brand_counts = []
brand_counts_hash = Hash.new()
items = Item.left_outer_joins(:skus).where(category_id: params[:id]).pluck(:brand_id, :number_of_stock, :item_id)
items.each do |item|
brand_id = item[0]
stock = item[1]
if brand_counts_hash.has_key?(brand_id)
item_count_arry = brand_counts_hash[brand_id]
stock_available_item_count = item_count_arry[0]
all_item_count = item_count_arry[1]
if stock > 0
brand_counts_hash[brand_id] = [stock_available_item_count + 1, all_item_count + 1]
else
brand_counts_hash[brand_id] = [stock_available_item_count, all_item_count + 1]
end
else
stock_available_item_count = 0
all_item_count = 0
if stock > 0
stock_available_item_count += 1
all_item_count += 1
brand_counts_hash[brand_id] = [stock_available_item_count, all_item_count]
else
all_item_count += 1
brand_counts_hash[brand_id] = [stock_available_item_count, all_item_count]
end
end
end
brand_counts_hash.each do |key, value|
stock_available_item_count = value[0]
all_item_count = value[1]
brand_counts << {
id: key,
name: get_brand_name(key),
stock_available_item_count: stock_available_item_count,
all_item_count: all_item_count
}
end
#brand_counts = brand_counts
render 'brands/counts/index', formats: :json
end
def get_brand_name(brand_id)
brand = Brand.find_by(id: brand_id)
brand.name unless brand == nil
end
Is there a way to optimize this further without multiple loops maybe?
Assume your Brand model also has the following association defined
has_many :items
and the final result you want is like
{
"brandCounts":[
{
"id":7006,
"name":"Brand 01",
"stockAvailableItemCount":50,
"allItemCount":60
},
{
"id":20197,
"name":"Brand 02"
"availableItemCount":150,
"allItemCount":660
}
]
}
The following code may not work when you copy and paste to your project. But it demonstrate how this problem can be solved with less code
Brand.includes(items: :skus).all.map do |brand|
{
id: brand.id,
name: brand.name,
stockAvailableItemCount: brand.items.count,
allItemCount: brand.items.map {|item| item.skus.sum(:number_of_stock)}.sum
}
end
if you need json format, just use to_json to the result of above code.
I have a hash:
my_hash = {
blue: 2,
red: 3,
purple: 4,
}
I have a Model with corresponding db-table:
____________________
| id | color | count |
----------------------
| | | |
----------------------
I want to put my hash in the table like this:
____________________
| id | color | count |
----------------------
| 1 | blue | 2 |
| 2 | red | 3 |
| 3 | purple| 4 |
----------------------
So my question is, How can I write code that persists the hash to the corresponding db-table?
This can easily be done as below,
my_hash.each { |k,v| Model.create(color: k, count: v) }
I'm newbie in a backend development and stuck with a simple request and ask for help.
I am trying to get a simple join:
select * from product a, product_barcode b
where a.productid = b.productid
Structure of the classes:
Product
class Product extends ManagedObject<product> implements product {}
class product {
#primaryKey
int productid;
String rusname;
String engname;
ManagedSet<Product_barcode> products;
}
Product_barcode
Class Product_barcode extends ManagedObject<product_barcode>
implements product_barcode {}
class product_barcode {
#primaryKey
int productid;
String barcode;
#Relate(#products)
Product product;
}
Request
#Operation.get()
Future<Response> getProducts() async {
final productQuery = Query<Product>(context)..join(set: (a) => a.products);
final res = await productQuery.fetch();
return Response.ok(res);
}
When i make a request I am getting error:
SELECT t0.productid,t0.rusname,t0.engname,t1.productid,t1.barcode,t1.product_productid FROM product t0 LEFT OUTER JOIN product_barcode t1 ON t0.productid=t1.product_productid
column t1.product_productid does not exist
What I am doing wrong? I do not have a column product_productid in my database
Update
Table structure
drugs=# \dt product_barcode
List of relations
Schema | Name | Type | Owner
--------+-----------------+-------+----------
public | product_barcode | table | druguser
(1 row)
drugs=# \d product_barcode
Table "public.product_barcode"
Column | Type | Collation | Nullable | Default
-----------+-------------------+-----------+----------+---------
productid | integer | | not null |
barcode | character varying | | not null |
Indexes:
"product_barcode_pk" PRIMARY KEY, btree (productid, barcode)
drugs=# \dt product
List of relations
Schema | Name | Type | Owner
--------+---------+-------+----------
public | product | table | druguser
(1 row)
drugs=# \d product
Table "public.product"
Column | Type | Collation | Nullable | Default
-------------------------+--------+-----------+----------+---------
productid | bigint | | not null |
rusname | text | | |
engname | text | | |
registrationdate | text | | |
dateofcloseregistration | text | | |
registrationnumber | text | | |
composition | text | | |
zipinfo | text | | |
producttypecode | text | | |
marketstatusid | text | | |
Indexes:
"product_pkey" PRIMARY KEY, btree (productid)
I am trying to query solely the IDs of clients that meet specific criteria from a source tab to an output tab and fill 2 columns with static values and 2 columns with dynamic values, based on criteria.
In the source tab I have:
+-----------------------+------+
| Status | ID |
+-----------------------+------+
| Retired/Deceased | 2a33 |
+-----------------------+------+
| Liquidation | 1sTR |
+-----------------------+------+
| Dissolved | 3B76 |
+-----------------------+------+
| Released from company | 463z |
+-----------------------+------+
| Active | 557g |
+-----------------------+------+
| In progress | zz34 |
+-----------------------+------+
| Demo | cc56 |
+-----------------------+------+
Please note, that there are 7 criteria values and I need the output for only 4 of them. Meaning that I need 4 values, based on which there will be binary fill of dynamic columns. The other 3 values are obsolete.
From these 4 values, if I have eg. Criteria 1, then I will have one fill of the 2 dynamic columns, if not (for the other 3 values) I will have other fill values.
So I guess simply going with a binary solution for the selection of the specific values is not applicable.
In the output tab logic:
+--------------------------------------------------------------------------------+
| Output tab |
+--------------------------------------------------------------------------------+
| ID | Status | Reason | Comment | Detail |
+----+--------+--------+----------------------------+----------------------------+
| A1 | Static | Static | If criteria = criteria 1, | If criteria = criteria 1, |
| | | | then null, | then value 1, |
| | | | else criteria value | else value 2 |
+----+--------+--------+----------------------------+----------------------------+
| B1 | Static | Static | If criteria = criteria 1, | If criteria = criteria 1, |
| | | | then null, | then value 1, |
| | | | else criteria value | else value 2 |
+----+--------+--------+----------------------------+----------------------------+
| C1 | Static | Static | If criteria = criteria 1, | If criteria = criteria 1, |
| | | | then null, else | then value 1, |
| | | | criteria value | else value 2 |
+----+--------+--------+----------------------------+----------------------------+
| D1 | Static | Static | If criteria = criteria 1, | If criteria = criteria 1, |
| | | | then null, | then value 1, |
| | | | else criteria value | else value 2 |
+----+--------+--------+----------------------------+----------------------------+
| E1 | Static | Static | If criteria = criteria 1, | If criteria = criteria 1, |
| | | | then null, | then value 1, |
| | | | else criteria value | else value 2 |
+----+--------+--------+----------------------------+----------------------------+
| F1 | Static | Static | If criteria = criteria 1, | If criteria = criteria 1, |
| | | | then null, | then value 1, |
| | | | else criteria value | else value 2 |
+----+--------+--------+----------------------------+----------------------------+
| G1 | Static | Static | If criteria = criteria 1, | If criteria = criteria 1, |
| | | | then null, | then value 1, |
| | | | else criteria value | else value 2 |
+----+--------+--------+----------------------------+----------------------------+
Dummy output tab:
+-----------------------+------+-------------------+-------------+------------------+---------------------------------+
| Status | ID | Status | Reason | Comment | Detail |
+-----------------------+------+-------------------+-------------+------------------+---------------------------------+
| Retired/Deceased | 2a33 | Unable to proceed | Unspecified | Retired/Deceased | Retired/No longer in business |
+-----------------------+------+-------------------+-------------+------------------+---------------------------------+
| Liquidation | 1sTR | Unable to proceed | Unspecified | Liquidation | Retired/No longer in business |
+-----------------------+------+-------------------+-------------+------------------+---------------------------------+
| Dissolved | 3B76 | Unable to proceed | Unspecified | Dissolved | Retired/No longer in business |
+-----------------------+------+-------------------+-------------+------------------+---------------------------------+
| Released from company | 463z | Unable to proceed | Unspecified | (null) | No longer works for the company |
+-----------------------+------+-------------------+-------------+------------------+---------------------------------+
The column 'Status' is not required. I added it just for reference and readability.
Apologies, but I have corporate security restrictions for sharing links to Google Sheets.
The part that I struggle most with is that in column 4 (the first one from the dynamic ones) needs to return the value of the criteria from column 2 from the source tab.
So far I have worked my way around the first part of the query, where I QUERY the IDs based on multiple criteria, labelled and filled the static values columns.
=QUERY(Data!$A$3:$BN,
"SELECT B, 'Unable to proceed', 'Unspecified'
WHERE A = 'Retired/Deceased'
OR A = ''Liquidation'
OR A = 'Dissolved'
OR A = 'Released from company'
AND A IS NOT NULL
LABEL 'Unable to proceed' 'Unspecified' , 'Status' 'Reason'", 1)
However, I am struggling with the dynamic columns, based on multiple criteria.
I looked up ARRAYFORMULA with IFERROR and VLOOKUP in a nested QUERY, but was not able to work my way around it.
Also, I am quite interested in how this would work if there were more than 2 options of values to fill columns 3 and 4 in the output tab.
As far as I know, the way to work around 2 values based on criteria is to nest an IFERROR function to make it binary. But what if there were more than 2 values to fill the arrays with?
based on status:
=QUERY({QUERY(Data!$A$1:$B,
"SELECT B, 'Unable to proceed', 'Unspecified'
WHERE A = 'Retired/Deceased'
OR A = 'Liquidation'
OR A = 'Dissolved'
OR A = 'Released from company'
AND A IS NOT NULL
LABEL 'Unable to proceed''Status', 'Unspecified''Reason'", 1),
QUERY(ARRAYFORMULA(IFERROR(VLOOKUP(
QUERY(Data!$A$2:$B,
"SELECT A
WHERE A = 'Retired/Deceased'
OR A = 'Liquidation'
OR A = 'Dissolved'
OR A = 'Released from company'
AND A IS NOT NULL", 0),
{"Retired/Deceased", "Retired/Deceased", "Retired/No longer in business";
"Liquidation", "Liquidation", "Retired/No longer in business";
"Dissolved", "Dissolved", "Retired/No longer in business";
"Released from company", "", "No longer works for the company"}, {2, 3}, 0), )),
"LABEL Col1 'Comment', Col2 'Detail'", 0)}, , 0)
based on ID:
=QUERY({QUERY(Data!$A$1:$B,
"SELECT B, 'Unable to proceed', 'Unspecified'
WHERE A = 'Retired/Deceased'
OR A = 'Liquidation'
OR A = 'Dissolved'
OR A = 'Released from company'
AND A IS NOT NULL
LABEL 'Unable to proceed''Status', 'Unspecified''Reason'", 1),
QUERY(ARRAYFORMULA(IFERROR(VLOOKUP(
QUERY(Data!$A$2:$B,
"SELECT B
WHERE A = 'Retired/Deceased'
OR A = 'Liquidation'
OR A = 'Dissolved'
OR A = 'Released from company'
AND A IS NOT NULL", 0),
{"2a33", "Retired/Deceased", "Retired/No longer in business";
"1sTR", "Liquidation", "Retired/No longer in business";
"3B76", "Dissolved", "Retired/No longer in business";
"463z", "", "No longer works for the company"}, {2, 3}, 0), )),
"LABEL Col1'Comment', Col2'Detail'", 0)}, , 0)
I am struggling with one code line. It is a Key generation Line for a Expert Adviser. Can someone help me figure out how I can generate key by using this line:
int key=3*(StringToInteger(StringSubstr(IntegerToString(AccountNumber()), 0, 3)))+333333;
And what is the problem?
int accountNumber = AccountNumber();
string accountNumberString = IntegerToString(accountNumber);
string accountNumberStringFirst3Digits=
StringSubstr(accountNumberString,0,3);
int accountNumberFirstThreeDigits = StringToInteger(accountNumberStringFirst3Digits);
int accountNumberFirstThreeDigitsMultiplied = 3 * accountNumberFirstThreeDigits;
int key = accountNumberFirstThreeDigitsMultiplied + 333333;
Can someone help me figure out how to generate key by this line?
Welcome, certainly, let's look on that :
int key = 3*(StringToInteger(StringSubstr(IntegerToString(AccountNumber()), 0, 3)))+333333;
Your code actually means this:
// +------------------------------------------------------------------------------- type declaration
// | +--------------------------------------------------------------------------- variable name definition
// | | +------------------------------------------------------------------------- assignment operator
// | | | +----------------------------------------------------------------------- compile-time integer constant
// | | | | +--------------------------------------------------------------------- multiply operator
// | | | | | +-------------------------------------------------- MT4 system function: StringToInteger( aString )
// | | | | | | +------------------------------------ MT4 system function: StringSubstr( aString, aPosToStartSubstrFrom, aSubstrLength )
// | | | | | | | +------------------- MT4 system function: IntegerToString( aIntNum ) | |
// | | | | | | | | +---- MT4 system function: AccountNumber() | |
// | | | | | | | | | | |
// | | | | | | | | | +------------------------------------------------------------------+ |
// | | | | | | | | | | +------------------------------------------------------------------------------+
// | | | | | | | | | | |
int key = 3 * ( StringToInteger( StringSubstr( IntegerToString( AccountNumber() ), 0, 3 ) ) )
+ 333333;
// | ||
// +------||----------------------------------------------------------------- add operator
// +|----------------------------------------------------------------- compile-time integer constant
// +----------------------------------------------------------------- literal MQL4-language syntax-terminator
The code above both defines and generates a fair integer value, so wherever your Expert Advisor code refers to a value of key, this calculated value will be used ( see also the documentation about the New-MQL4 scope-of-validity, inside which this variable remains visible ).