Is there a way via Scala with Slick database query and access library (or using other tricks - dare I say mocks?) to get max_allocated_packets from JDBC-read connection properties from a Slick-style DB connection to MySQL?
As I suspect, the code makes several touch type actions at deeper levels and this connection property is then populated.
Ex: Once a connection is made in com.mysql.cj.jdbc.ConnectionImpl ... using Scala with the Slick library... the value for the JDBC connect property of max_allocated_packets is within the object (debugged in IntelliJ). How can I extract this value or obtain it in higher level code as asked above?
Of course I can query the DB directly to get that value, but I am hoping I can extract this property after the setup phase.
If the value is publically available on a connection, you could try to use SimpleDBIO action to access the JDBC-level values.
See: https://scala-slick.org/doc/3.2.0/dbio.html#jdbc-interoperability
It would be of the form:
val getMaxPacketAction = SimpleDBIO[Int] { database =>
// make use of database.connection here
}
However, this is still going to the database for a connection, so it may be just easier to query for the value you want.
When I tried to use FireDAC FDQuery with MySQL database I got the following error:
Cannot perform this operation on an open dataset.
query.Open(....my connection string to MySQL....);
try
query.ExecSql;
finally
query.Close;
I filled the FDQuery by double-clicking on the icon on the form. I also
connected to the database to test it. It gave back the results correctly.
I would like to use it from code, but it doesn't work, so
I debugged it. I always get to the breakpoint: query.Close;
You can't call Open and ExecSQL on the same SQL, because they do different things.
Use Open when the query will return a result set, which means for a SELECT. Use ExecSQL when the query does not return a result set, which means for an INSERT, DELETE or UPDATE.
I can't tell you which one applies to your situation, because you failed to include your SQL in your post.
I don't know about FireDAC specifically, but in general with these kind of database components, for queries not returning a result set, thus suitable for ExecSQL, you would want to use ExecSQL on the Connection object, in this case TFDConnection. (Which would presumably be the Connection object that your FDQuery object is connected to.)
http://docwiki.embarcadero.com/RADStudio/Rio/en/Executing_Commands_(FireDAC)
Apparently there is an ExecSQL method on TFDCustomQuery, but I'm not sure why you would use that, and as you discovered, it doesn't work if the query is already in use.
I'm trying to build a Data Integration job uses pass through to extract data from a view in a MySQL database.
Wev'e been using pass through a lot in the project, mostly extracting data from Redshift,
however with MySQL I was not able to do make it work properly.
It keeps complaining a table is missing even though when pass through is off, view is found and data is extracted...
tried every trick I know, starting from enabling case-sensitive DBMS object names, to manually remove single/double quotes from the statement just in case MySQL confuses confuses it with something else...
No luck.
ODBC driver is [MySQL][ODBC 5.3(a) Driver][mysqld-5.5.53].
Ran on a Windows environment.
Any idea how to solve this?
Thank you in advance.
EDIT
So, first of all, one correction (even though not that important - I extract from a view, not a table).
This is the code generated by SAS Create Table transformation, pass through enabled. I only put an asterisk instead of the full list of columns:
proc sql;
connect to ODBC
(
READBUFF=10000 DATASRC="cmp.web_api" AUTHDOMAIN="MYSQL_CMP_Auth"
);
create table work."W7ZZZKOC"n as
select
*
from connection to ODBC
(
select
V_BI_ACCOUNT.ACCOUNT_NAME,
V_BI_ACCOUNT.ACQUISITION_SOURCE__C,
V_BI_ACCOUNT.ZUORA__ACTIVE__C,
V_BI_ACCOUNT.ADDRESS_LINE_1__C,
V_BI_ACCOUNT.ADDRESS_LINE_2__C,
V_BI_ACCOUNT.ADDRESS_LINE_3__C,
V_BI_ACCOUNT.AGREEMENT_DATE,
V_BI_ACCOUNT.AGREEMENT_LEGAL_CLAUSE_1__C,
V_BI_ACCOUNT.AGREEMENT_LEGAL_CLAUSE_2__C,
V_BI_ACCOUNT.PERSONBIRTHDATE,
V_BI_ACCOUNT.BLOCKED_REASON__C,
V_BI_ACCOUNT.BRAND__C,
V_BI_ACCOUNT.CPN__C,
V_BI_ACCOUNT.ACCCREATEDBYID,
V_BI_ACCOUNT.ACCCREATEDDATE,
V_BI_ACCOUNT.CURRENCY_PREFERENCE__C,
V_BI_ACCOUNT.CUSTOMER_FULL_NAME__PC,
V_BI_ACCOUNT.ACCOUNTID,
V_BI_ACCOUNT.ZUORA__CUSTOMERPRIORITY__C,
V_BI_ACCOUNT.DELIVERY_SALUTATION__C,
V_BI_ACCOUNT.DISPLAY_NAME,
V_BI_ACCOUNT.PERSONEMAIL,
V_BI_ACCOUNT.EMAILKEY__C,
V_BI_ACCOUNT.FACEBOOKKEY,
V_BI_ACCOUNT.FIRSTNAME,
V_BI_ACCOUNT.GENDER__C,
V_BI_ACCOUNT.PHONE,
V_BI_ACCOUNT.ACCLASTACTIVITYDATE,
V_BI_ACCOUNT.ACCLASTMODIFIEDDATE,
V_BI_ACCOUNT.LASTNAME,
V_BI_ACCOUNT.OTHER_EMAIL__C,
V_BI_ACCOUNT.PI_TYPE__C,
V_BI_ACCOUNT.ACCPARENTID,
V_BI_ACCOUNT.POSTCODE__C,
V_BI_ACCOUNT.PRIMARY_ACCOUNT_OF_THIS_CUSTOMER,
V_BI_ACCOUNT.ACCPRIMARY__C,
V_BI_ACCOUNT.ACCREASON_FOR_STATUS__C,
V_BI_ACCOUNT.ZUORA__SLA__C,
V_BI_ACCOUNT.ZUORA__SLASERIALNUMBER__C,
V_BI_ACCOUNT.SALUTATION,
V_BI_ACCOUNT.ACCSYSTEMMODSTAMP,
V_BI_ACCOUNT.PERSONTITLE,
V_BI_ACCOUNT.ZUORA__UPSELLOPPORTUNITY__C,
V_BI_ACCOUNT.X_CODE__C,
V_BI_ACCOUNT.ZUORA__ACCOUNT_ID__C,
V_BI_ACCOUNT.ZUORA__PAYMENTMETHODID__C,
V_BI_ACCOUNT.CITY,
V_BI_ACCOUNT.ORIGINAL_CREATED_DATE,
V_BI_ACCOUNT.SOURCE_SYSTEM_ID,
V_BI_ACCOUNT.STATUS,
V_BI_ACCOUNT.ZUORA__CONTACT_ID,
V_BI_ACCOUNT.ACCISDELETED,
V_BI_ACCOUNT.BILLING_ACCOUNT_NAME,
V_BI_ACCOUNT.ACZCREATEDDATE,
V_BI_ACCOUNT.ACZSYSTEMMODSTAMP,
V_BI_ACCOUNT.ACZLASTACTIVITYDATE,
V_BI_ACCOUNT.ZUORA__ACCOUNT__C,
V_BI_ACCOUNT.ZUORA__ACCOUNTNUMBER__C,
V_BI_ACCOUNT.ZUORA__AUTOPAY__C,
V_BI_ACCOUNT.ZUORA__BALANCE__C,
V_BI_ACCOUNT.ZUORA__CREDITCARDEXPIRATION__C,
V_BI_ACCOUNT.ZUORA__CURRENCY__C,
V_BI_ACCOUNT.ZUORA__MRR__C,
V_BI_ACCOUNT.ZUORA__PAYMENTTERM__C,
V_BI_ACCOUNT.ZUORA__PURCHASEORDERNUMBER__C,
V_BI_ACCOUNT.ZUORA__LASTINVOICEDATE__C,
V_BI_ACCOUNT.COUNTRY_NAME,
V_BI_ACCOUNT.COUNTRY_CODE,
V_BI_ACCOUNT.FAVOURITE_FOOTBALL_CLUB,
V_BI_ACCOUNT.COUNTY
from
web_api.V_BI_ACCOUNT as V_BI_ACCOUNT
);
%rcSet(&sqlrc);
disconnect from ODBC;
quit;
And again, when I extract data without pass through - works successfully,
I found out the problem was a column name exceeds 32 positions.
As SAS supports up column names up to 32,
the query fails to find PRIMARY_ACCOUNT_OF_THIS_CUSTOMER as the original column name is PRIMARY_ACCOUNT_OF_THIS_CUSTOMER__C.
EDIT
One more thing I found out is, MySQL doesn't like specifying schema name nor aliases.
Therefore,
From clause to only specify table name i.e : 'from v_bi_account' rather than 'web_api.v_bi_account'
and do not use aliases i.e use 'from v_bi_account' rather than 'from v_bi_account as v_bi_account'
Thank you guys so much for your help.
I have been getting this annoying exception while trying to create a native query with my entity manager. The full error message is:
java.lang.IllegalStateException: During synchronization a new object was found through a relationship that was not marked cascade PERSIST: com.model.OneToManyEntity2#61f3b3b.
at org.eclipse.persistence.internal.sessions.RepeatableWriteUnitOfWork.discoverUnregisteredNewObjects(RepeatableWriteUnitOfWork.java:313)
at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.calculateChanges(UnitOfWorkImpl.java:723)
at org.eclipse.persistence.internal.sessions.RepeatableWriteUnitOfWork.writeChanges(RepeatableWriteUnitOfWork.java:441)
at org.eclipse.persistence.internal.jpa.EntityManagerImpl.flush(EntityManagerImpl.java:874)
at org.eclipse.persistence.internal.jpa.QueryImpl.performPreQueryFlush(QueryImpl.java:967)
at org.eclipse.persistence.internal.jpa.QueryImpl.executeReadQuery(QueryImpl.java:207)
at org.eclipse.persistence.internal.jpa.QueryImpl.getSingleResult(QueryImpl.java:521)
at org.eclipse.persistence.internal.jpa.EJBQueryImpl.getSingleResult(EJBQueryImpl.java:400)
The actual code that triggers the error is:
Query query;
query = entityManager.createNativeQuery(
"SELECT MAX(CAST(SUBSTRING_INDEX(RecordID,'-',-1) as Decimal)) FROM `QueriedEntityTable`");
String recordID = (query.getSingleResult() == null ?
null :
query.getSingleResult()
.toString());
This is being executed with an EntityTransaction in the doTransaction part. The part that is getting me with this though is that this is the first code to be executed within the doTransaction method, simplified below to:
updateOneToManyEntity1();
updateOneToManyEntity2();
entityManager.merge(parentEntity);
The entity it has a problem with "OneToManyEntity1" isn't even the table I'm trying to create the query on. I'm not doing any persist or merge up until this point either, so I'm also not sure what is supposedly causing it to be out of sync. The only database work that's being done up until this code is executed is just pulling in data, not changing anything. The foreign keys are properly set up in the database.
I'm able to get rid of this error by doing as it says and marking these relationships as Cascade.PERSIST, but then I get a MySQLContrainstraViolationException on the query.getSingleResult() line. My logs show that its doing some INSERT queries right before this, so it looks like its reaching the EntityManager.merge part of my doTransaction method, but the error and call stack point to a completely different part of the code.
Using EclipseLink (2.6.1), Glassfish 4, and MySQL. The entitymanager is using RESOURCE_LOCAL with all the necessary classes listed under the persistence-unit tag and exclude-unlisted-classes is set to false.
Edit: So some more info as I'm trying to work through this. If I put a breakpoint at the beginning of the transaction and then execute entityManager.clear() through IntelliJ's "Evaluate Expression" tool, everything works fine at least the first time through. Without it, I get an error as it tries to insert empty objects into the table.
Edit #2: I converted the nativeQuery part into using the Criteria API and this let me actually make it through my code so I could find where it was unintentionally adding in a null object to my entity list. I'm still just confused as to why the entity manager is caching these errors or something to the point that creating a native query is breaking because its still trying to insert bad data. Is this something I'd need to call EntityManager.clear() before doing each time? Or am I supposed to call this when there is an error in the doTransaction method?
So after reworking the code and setting this aside, I stumbled on at least part of the answer to my question. My issue was caused by the object being persisted prior to the transaction starting. So when I was entering my transaction, it first tried to insert/update data from my entity objects and threw an error since I hadn't set the values of most of the non-null columns. I believe this is the reason I was getting the cascade errors and I'm positive this is the source of the random insert queries I saw being fired off at the beginning of my transaction. Hope this helps someone else avoid a lot of trouble.
I have a 'user' table with a field name 'process_salary?' which has a boolean datatype
#user = User.create(params[:user])
if #user.process_salary?
//some code here
else
//some code here
end
When I create a new object of user and check for process_salary it gives me following error
NoMethodError: undefined method `process_salary?' for #<User:0xb6ac2f68>
Why does this error occur? Can I avoid it without changing my column name?
When I check it with the debugger it crashes the first time, but after that it runs properly
The question-mark has a special meaning in ActiveRecord. It can be used to check whether a field is true. You are using it as part of your field name which wasn't such a good idea. You could try if #user.process_salary?? exists but I think ultimately it is easiest to change your database column to be called 'process_salary'.
Side note: The 'rails console' is really helpful for playing around with models.
As cellcortex posted, question marks at the end of column names are tricky in Rails. If you need to have it there for legacy reasons, you might be able access the attribute as follows:
#user['process_salary?']
or the more verbose:
#user.read_attribute['process_salary?']
You can of course test for nil using .nil?.