I want to write a method that given:
Name of the table T as string.
Name of Field to Value F1 as string.
Name of Field to Description F2 as string.
Name of Field to Information F3 as string.
Return and IQueryable<TypeItem> with the records of the table T, and fields F1, F2, F3
TypeItem contain the prop Value, Description and Information as string.
Related
I have a table with the following field values:
I want to do a select where I can match a value from this keyword column. For example:
SELECT templateid FROM public.templates WHERE keyword='Yes'
I don't want to use LIKE because in the case one of the comma-separated values is Yessy then I will get a return and that's not correct.
It has to be an exact match of one of the comma separated values.
Any clue?
You can convert the string into an array:
SELECT templateid
FROM public.templates
WHERE 'Yes' = any(string_to_array(keyword, ','))
"b" ~ meta[update b:1b from ([]a:1 2) where a=3][`b;`t]
But how does q knows what type should it be in the column b without any matched rows (where a=3) in update expression?
It infers the type from your statement, it doesn't matter if there was a match or not. It takes the null of whatever type you've specified for the column.
Same thing if there was a match:
q)update b:.z.D from ([]a:1 2) where a=2
a b
------------
1
2 2021.05.14
It fills the matches with your value, but the non-matches get the corresponding null for that datatype. Boolean is a grey area as there technically isn't a null but 0b is the assumed null Boolean
When I created the table Tab, I specified the columns as string,
Tab: ([Key1:string()] Col1:string();Col2:string();Col3:string())
But the column datatype (t) is empty. I suppose specifying the column as string has no effect.
meta Tab
c t f a
--------------------
Key1
Col1
Col2
Col3
After I do a bulk upsert in Java...
c.Dict dict = new c.Dict((Object[]) columns.toArray(new String[columns.size()]), data);
c.Flip flip = new c.Flip(dict);
conn.c.ks("upsert", table, flip);
The datatypes are all symbols:
meta Tab
c t f a
--------------------
Key1 s
Col1 s
Col2 s
Col3 s
How can I specify the datatype of the columns as string and have it remain as string?
You cant define a column of the empty table with as strings as they are merely lists of lists of characters
You can just set them as empty lists which is what your code is doing.
But the column will then take on the type of whatever data is inserted into it.
Real question is what is your java process sending symbols when it should be sending strings. You need to make the change there before publishing to KDB
Note if you define as chars you still wont be able to upsert strings
q)Tab: ([Key1:`char$()] Col1:`char$();Col2:`char$();Col3:`char$())
q)Tab upsert ([Key1:enlist"test"] Col1:enlist"test";Col2:enlist"test";Col3:enlist "test")
'rank
[0] Tab upsert ([Key1:enlist"test"] Col1:enlist"test";Col2:enlist"test";Col3:enlist "test")
^
q)Tab: ([Key1:()] Col1:();Col2:();Col3:())
q)Tab upsert ([Key1:enlist"test"] Col1:enlist"test";Col2:enlist"test";Col3:enlist "test")
Key1 | Col1 Col2 Col3
------| --------------------
"test"| "test" "test" "test"
KDB does not allow to define column types as list during creation of table. So that means you can not define your column type as String because that is also a list.
To do that only way is to define column as empty list like:
q) t:([]id:`int$();val:())
Then when you insert data to this table the column will automatically take type of that data.
q)`t insert (4;"row1")
q) meta t
c | t f a
---| -----
id | i
val| C
In your case, one option is to send string data from your Java process as mentioned by user 'emc211' or other option is to convert your data to string in KDB process before insertion.
Looking at postgres documentation for JSON functions (https://www.postgresql.org/docs/9.6/static/functions-json.html), there is a section I don't understand about expanding a JSON object into a set of rows.
The docs give a sample use of this function: json_populate_recordset(base anyelement, from_json json) as select * from json_populate_recordset(null::myrowtype, '[{"a":1,"b":2},{"a":3,"b":4}]')
But I'm not sure what that first argument (null::myrowtype) is -- a table definition?
The description of this function is: Expands the outermost array of objects in from_json to a set of rows whose columns match the record type defined by base (see note below).
None of the notes at the bottom seemed relevant. I'm hoping for a better explanation with sample code to understand it all.
The 2nd notice is the one of interest in the doc as it explains how missing fields/values are handled
Note: In json_populate_record, json_populate_recordset, json_to_record
and json_to_recordset, type coercion from the JSON is "best effort"
and may not result in desired values for some types. JSON keys are
matched to identical column names in the target row type. JSON fields
that do not appear in the target row type will be omitted from the
output, and target columns that do not match any JSON field will
simply be NULL.
json_populate_recordset maps the name of the json object to the column name in the table given as first argument.
create table public.test (a int, b text);
select * from json_populate_recordset(null::public.test, '[{"a":1,"b":"b2"},{"a":3,"b":"b4"}]');
a | b
---+----
1 | b2
3 | b4
(2 rows)
--Wrong column name:
select * from json_populate_recordset(null::public.test, '[{"a":1,"c":"c2"},{"a":3,"c":"c4"}]');
a | b
---+---
1 |
3 |
(2 rows)
--Wrong datatype:
select * from json_populate_recordset(null::public.test, '[{"a":1.1,"b":22},{"a":3.1,"b":44}]');
ERROR: invalid input syntax for integer: "1.1"
Alternatively, instead of using the column name/type from an existing table, you can define the columns on the fly
select * from json_to_recordset('[{"a":1,"b":"foo"},{"a":"2","c":"bar"}]') as x(a int, b text);
a | b
---+-----
1 | foo
2 |
(2 rows)
--> note that default type cast occurs ("2" is mapped to 2), missing fields are ignored (b, in second record) as well as fields not defined (c)
Accept a customer number and then output the details of each order and items to an editor widget.
Here customer , order ,order-line and items are table names.
where as customer and order tables have cust-num as common field , order and order-line(table-name) and order have order-num as common field , order-line and item have item-num as common field.
now i have to use a fill-in (f1 is object name) to get the cust-num and use a search button (search1 as object name) to find the corresponding fields and display them in the editor widget ( editor-1 as object name).
define temp-table ttcustomer
field custnum like customer.cust-num
field cname like customer.name
field orders like order.order-num
field items like item.item-num
field itemname like item.item-name .
find first customer WHERE customer.cust-num = input f1 NO-LOCK .
create ttcustomer .
assign
ttcustomer.custnum = customer.cust-num
ttcustomer.cname = customer.name.
for each order WHERE Order.cust-num = input f1 NO-LOCK .
assign
ttcustomer.orders = order.order-num.
for each order-line where order-line.order-num = order.order-num no-lock.
for each item where item.item-num = order-line.item-num no-lock.
assign
ttcustomer.items = item.item-num
ttcustomer.itemname = item.item-name.
end.
end.
end.
i have written this code in search button .
how can i display the temp-table ttcustomer in editor widget please help me :)
You'd probably be better off using a browser instead of an editor. But if you are going to use an editor, this should give you what you need:
DEFINE VARIABLE edData AS CHARACTER NO-UNDO.
FOR EACH ttcustomer:
edData = edData + ttcustomer.items + ", " + ttcustomer.itemname + CHR(10).
END.
editor-1:SCREEN-VALUE = edData.
The editor is just text so you won't be able to do any record selection/manipulation like you can with a browser. And if you have many ttcustomer records, you run the risk of overflowing the 32k character string size limit.