What is the difference between the two statements below?
newTable = orginalTable
or
newTable.data(originalTable)
I suspect there is a performance benefit to the .data() method as it is more commonly used in standard AX.
Try this:
newTable = originalTable;
info(strfmt('%1 %2', newTable.recId, originalTable.recId);
newTable.data(originalTable);
newTable.insert();
info(strfmt('%1 %2', newTable.recId, originalTable.recId);
You'll see that the first statement just creates another one pointer to existing record. The second one creates new copy of existing record.
Related
I do voluntary work at an animal shelter. We have an application which uses a SQL Server 2019 database. I have created a view that includes a varbinary(max) column. The value in this column is a picture, stored in hexadecimal-format. I would like to convert this Hex-value to a base64-binary file and add these to the view as an extra column.
I found the perfect solution for my situation in SQL Server : hex to base64. The example provided converts 1 single hex-value into 1 base64-value. I now need to add this solution to my view, but I'm not having any success.
The offered solution:
DECLARE #TestBinHex varchar(max), #TestBinary varbinary(max), #Statement nvarchar(max);
SELECT #TestBinHex = '0x012345';
SELECT #Statement = N'SELECT #binaryResult = ' + #TestBinHex;
EXECUTE sp_executesql #Statement, N'#binaryResult varbinary(max) OUTPUT', #binaryResult=#TestBinary OUTPUT;
SELECT
CAST(N'' AS XML).value(
'xs:base64Binary(xs:hexBinary(sql:column("bin")))'
, 'VARCHAR(MAX)'
) Base64Encoding
FROM
(SELECT #TestBinary AS bin) AS bin_sql_server_temp;
A simplified version of my view:
SELECT
a.cat_id, a.catname, s.cat_id,
s.stay_id, s.shelter_handler, s.shelter_kennel, s.picture
FROM
dbo.animal AS a
OUTER APPLY
(SELECT TOP 1 *
FROM dbo.shelterdata
WHERE a.cat_id = s.cat_id
ORDER BY s.stay_id DESC) AS S
WHERE
(a.cat_id IS NOT NULL) AND (s.leave_date IS NULL)
The view shows an overview of all cats currently present in the shelter (leave_date is NULL). The reason for the TOP 1 is that sometimes shelter animals get returned, and the application then assigns a new stay_id. To prevent duplicate values from the join, I only return the value of the most recent stay_id.
What I am trying to achieve: the second table (dbo.shelterdata) includes the picture, stored in hex value. I'd like to add a column Base64Encoding to the view which includes the converted value.
My attempts
I was successful in replacing the static value '0x012345' by a SELECT statement. But the way the solution is formatted, it only allows for one input value. So I had to restrict it with a WHERE clause. It is obvious to me that I need to make a subquery which inputs the hex value based on the unique cat_id. However, it has been many years since I worked with variable, so I'm struggling with the formatting of the statement.
My request
Does anyone have a suggestion how to build the conversion into the view?
Any assistance would be greatly appreciated.
After searching for a few more hours, I stumbled onto the solution. Maybe it will help someone else in the future. The solution is remarkably simple, as is often the case.
My view, mentioned above, is called dbo.shelter_view
select sv.picture,sv.cat_id,
cast('' as xml).value(
'xs:base64Binary(sql:column("sv.picture"))', 'varchar(max)'
) as Base64Encoding
from dbo.shelter_view as SV
I feel like this is one of those "if you're careful you can do it" scenarios that Oracle just doesn't want to let me do.
My problem is that I have a single configuration table that I want to enable inheritance via Triggers. Think an Employee table with a SUPERVISOR ID column, and 'inherited' SUPERVISOR NAME that self populates if the ID is changed.
I'd like to do a simple self-lookup to capture a value from another row at time of INS/UPD. But Oracle is rejecting as a mutating trigger error.
My code is essentially:
TRIGGER UPD_CHILD_RECORD
BEFORE INSERT OR UPDATE
ON MYSCHEMA.FAKE_EMPLOYEE
FOR EACH ROW
WHEN (NEW.SUPERVISOR_ID IS NOT NULL)
BEGIN
IF INSERTING OR UPDATING
THEN
:NEW.SUPERVISOR_NAME = (
SELECT MAX(NAME)
FROM MYSCHEMA.FAKE_EMPLOYEE
WHERE EMPLOYEE_ID = :NEW.SUPERVISOR_ID
);
END IF;
END UPD_CHILD_RECORD
;
thanks.
This is a normal behavior. Oracle protects you from inconsistent data that you may get accessing a table which is already being updated.
Imagine this scenario.
You submit two update statements and have a trigger that selects from that same table. Let's assume that the first statement is successfully applied and the data gets changed. Now it's time for the second statement. What output would you expect from the select statement in the trigger? Should it return data as it was before the first update, or should it include the changes made? You probably think that Oracle should return the new data. But first, Oracle does not really know your intentions, and second, that would mean that your query is dependent on row order, which contradicts the relational algebra.
The solution for your problem is quite simple. You do not need the SUPERVISOR_NAME column at all. To get supervisor's name, simply join the table with itself and get the desired result, something like:
select t1.ID, t1.SUPERVISOR_ID, t2.NAME from FAKE_EMPLOYEE t1
left join FAKE_EMPLOYEE t2 on t1.SUPERVISOR_ID = t2.ID;
I am new to Oracle PL/SQL. I have found this package and it is called from a trigger. I just cannot figure exactly what this simple looking package code is doing.
It is called from a trigger as below:
IF INSERTING THEN
i := STATE_PKG_OVERRIDE_CN.AffectedRows.COUNT+1;
STATE_PKG_OVERRIDE_CN.AffectedRows(i).IDU := :new.IDU;
STATE_PKG_OVERRIDE_CN.AffectedRows(i).cn := :new.cn;
This is the package. Can somebody please explain the basics of what is it doing? does it return a value? change a value? what is AffectedRows RIDARRAY or EMPTY ?
create or replace PACKAGE STATE_PKG_OVERRIDE_CN
AS
TYPE rowid_cn IS RECORD
(
idu dirxml.USR.IDU%TYPE,
cn dirxml.USR.CN%TYPE
);
TYPE RIDARRAY IS TABLE OF rowid_cn INDEX BY BINARY_INTEGER;
AffectedRows RIDARRAY;
EMPTY RIDARRAY;
END;
I have googled EMPTY but found nothing, i believe it is creating a table of type record. The trigger is passing in a value of cn or IDU am i am familiar with these two values. But what is the package doing? or returning ? im confused.
Cheers
This is a bespoke package belonging to your organisation. (That's why Google wasn't helpful for you.) We cannot tell you for sure what it does or how it's used. But we can guess.
The package has no procedures or functions, it just defines array variables of a bespoke type, which can be used by other program units such as triggers. The trigger you posted assigns values to the array AffectedRows. Presumably this trigger fires FOR EACH ROW. Likely there is another trigger on the same table firing AFTER STATEMENT which reads that array and does some processing, then assigns AffectedRows := EMPTY to reset the array.
The purpose of this infrastructure is to pass state across trigger actions. A common reason for doing this is work around a mutating table exception. They are risky because state cannot be guaranteed; for instance if a insert fails before the AFTER STATEMENT trigger fires the AffectedRows array is not re-initialised, so subsequent processing will be incorrect (or will fail).
Since 11g Oracle provides compound triggers which remove the need for this sort of package. Find out more.
To investigate further, first you want to check USER_TRIGGERS to find other triggers on the table which owns the trigger you mentioned. If that doesn't help or you want to see whether other tables also use this package run this query:
select *
from user_dependencies
where referenced_type = 'PACKAGE'
and referenced_name = 'STATE_PKG_OVERRIDE_CN'
It begins with the package which
declares a type ROWID_CN as a record that contains two values: IDU and CN
syntax requires to create another type (RIDARRAY) which is based on previously declared ROWID_CN
affectedrows and empty are arrays whose type is RIDARRAY. Basically, you can imagine them as a table that has two columns, IDU and CN
Now, a trigger: piece of code you posted says that those 3 lines are executed when someone inserts a row into a table the trigger is based on. For example,
create or replace trigger trg_biu_emp
before insert or update on emp
for each row
declare
i number;
begin
if inserting then ...
Apparently, there's some code that is executed when updating, or even deleting rows.
Anyway:
i := ... line counts number of elements in affectedrows array (which is declared in the package) and adds 1 to that number. For example, if there were 3 elements, i would be 4.
...affectedrows(i).idu := :new.idu enters a new row into the array. Its ordinal number is i (4 in our example). As you're inserting a row into the table, trigger knows IDU column's :new value and puts it into the array. For example, if you used
insert into emp (idu, cn) values (100, 'A')
then affectedrows(4).idu = 100, while affectedrows(4).cn = 'A'
It is, probably, something similar with EMPTY array. Google can't return anything useful, it is just a custom-made array.
I have an issue that could be solved by implementing full aduting either with triggers or flash data archive but that's much more than is required.
So right now we are performing a merge which is updating a row when its present or inserting when its not. It works well and was easy to write. We now have a new requirement which is that users must know which rows have been updated or inserted. Yes this could be accomplished by introducing another field into the table, but thats not allowed because that would change the table. So we are forced to create one or two tables which will identify which rows are updated or inserted via the PK.
What I am hoping to do is take the existing MERGE statement and add the ability to insert into the secondary table, but I have not been able to find any merge statements which work that way, and INSERT ALL lacks the more complicated conditionals of the merge.
Here is the structure of the MERGE statement thats currently being used.
MERGE INTO EXISTING_TABLE ET USING TMP_TABLE TMP ON (HRR.ID = TMP.ID)
WHEN MATCHED THEN UPDATE SET
ET.ID = TMP.ID,
ET.TITLE_EN = TMP.TITLE_EN,
ET.TITLE_FR = TMP.TITLE_FR,
WHEN NOT MATCHED THEN INSERT (ID, TITLE_EN, TITLE_FR)
VALUES (TMP.ID, TMP.TITLE_EN, TMP.TITLE_FR);
Below is the way Im hoping to accomplish the MERGE INSERT ALL.
MERGE INTO EXISTING_TABLE ET USING TMP_TABLE TMP ON (HRR.ID = TMP.ID)
WHEN MATCHED THEN UPDATE
SET
ET.ID = TMP.ID,
ET.TITLE_EN = TMP.TITLE_EN,
ET.TITLE_FR = TMP.TITLE_FR,
INSERT INTO NEW_TABLE (ID, TYPE) VALUES (TMP.ID, 'U')
WHEN NOT MATCHED THEN INSERT ALL
INTO EXISTING_TABLE (ID, TITLE_EN, TITLE_FR) VALUES (TMP.ID, TMP.TITLE_EN, TMP.TITLE_FR),
INTO NEW_TABLE (ID, TYPE) VALUES (TMP.ID, 'I');
The only other way to reasonably accomplish this that I can see would be with a PLSQL block which works on row statements and would be slower.
At our site, we use after triggers to update audit stuff. It has an advantage of tracking the changes via program, or if someone fat fingers an update statement.
That might do the job for you.
I need to work with a SQL result set in order to do some processing for each column (medians, standard deviations, several control statements included)
The SQL is dynamic so I don't know the number of columns, rows.
First I tried to use temporary tables, views, etc to store the results, however I did not manage to overcome the 30 character limit of Oracle columns when using the below sql:
create table (or view or global temporary table) as select * from (
SELECT
DMTTBF_MAT_MATURATO_BILL_POS.MAT_V_COD_ANNOMESE,
SUM(DMTTBF_MAT_MATURATO_BILL_POS.MAT_N_NUM_EVENTI_CHZ +DMTTBF_MAT_MATURATO_BILL_POS. MAT_N_NUM_EVENTI) <-- exceeds the 30 character limit
FROM DMTTBF_MAT_MATURATO_BILL_POS
WHERE DMTTBF_MAT_MATURATO_BILL_POS.MAT_V_COD_ANNOMESE >= '201301'
GROUP BY DMTTBF_MAT_MATURATO_BILL_POS.MAT_V_COD_ANNOMESE
)
Second choice was to use some PL/SQL types to store the entire table information, so I could call it like in other programming languages (e.g. a matrix result[i][j]) but I could not find anything similar.
Third variant, using files for reading and writing: i did not try it yet; i'm still expecting a more elegant pl/sql solution
It's possible that I have the wrong approach here so any advice is more than welcome.
UPDATE: Modifying the input SQL is not an option. The program has to accept any select statement.
Note that you can alias both tables and fields. Using a table alias keeps references to it from producing walls of text in the query. Using one for a field gives it a new name in the output.
SELECT A.LONG_FIELD_NAME_HERE AS SHORTNAME
FROM REALLY_LONG_TABLE_NAME_HERE A
The auto naming adds _1 and _2 etc to differentiate the same column name coming from different table references. This often puts a field already borderline over the limit. Giving the fields names yourself bypasses this.
You can put the alias also in dynamic SQL:
sqlstr := 'create table (or view or global temporary table) as select * from (
SELECT
DMTTBF_MAT_MATURATO_BILL_POS.MAT_V_COD_ANNOMESE,
SUM(DMTTBF_MAT_MATURATO_BILL_POS.MAT_N_NUM_EVENTI_CHZ + DMTTBF_MAT_MATURATO_BILL_POS.MAT_N_NUM_EVENTI) AS '||SUBSTR('SUM(DMTTBF_MAT_MATURATO_BILL_POS.MAT_N_NUM_EVENTI_CHZ +DMTTBF_MAT_MATURATO_BILL_POS.MAT_N_NUM_EVENTI)', 1, 30)
||' FROM DMTTBF_MAT_MATURATO_BILL_POS
WHERE DMTTBF_MAT_MATURATO_BILL_POS.MAT_V_COD_ANNOMESE >= ''201301''
GROUP BY DMTTBF_MAT_MATURATO_BILL_POS.MAT_V_COD_ANNOMESE
)'