I just refactored into a power query function some code that process tables that has an specific structure.
Now, I need to pass another PowerQuery query (that returns a table with a compatible structure) to this function, but the parameter manager only allows to use strings, therefore I need to obtain access to the referenced table using an string with its name.
Any hints?
Related
I have several fields that contain exactly the same sql query! Is it possible to place the sql question centrally in APEX in the same way as list of values or as a function in oracle? I am using APEX 18.2
Here are two extended solutions
Pipelined SQL
https://smart4solutions.nl/blog/on-apex-lovs-and-how-to-define-their-queries/
Dynamic SQL
http://stevenfeuersteinonplsql.blogspot.com/2017/01/learn-to-hate-repetition-lesson-from.html
Call me dense, but I don't think I understand why you'd have multiple fields (presumably on the same form) whose source is the same SQL query.
Are you passing a parameter to the SQL to get a different value for each field?
If you are passing a parameter to the SQL query, why not create a database view to hold the query, then pass the parameter to the view. That way, if you need to change it, it's in one place.
If they really are all the same value from the same query, how about using the SQL for one field/page_item, then make the source for the others be the first page item?
I would create a hidden item with the query in the source as text and use &HIDDEN_ITEM_NAME. to reference its value in the source of any item I was trying to display the query.
Finally isolved it with a function and use the type PL/SQL Function Body returning SQL Query in APEX, then i have all in one place. I created a function in SQL developer that returns a SQL query.
In Data flow, I need to pass start Date and end date as runtime arguments and query bigquery for that date range and write output to day wise folders.
When we use ValueProvider, getStartDate().get() method is throwing java.lang.RuntimeException: Not called from a runtime context. If I hardcode some value when getStartDate().get().isAccessible() is false, template is being generated but the runtime arguments are not reflecting in job. It is always running with the hardcoded value during template creation.
Any suggestions ?
BigQueryIO takes a ValueProvider of the query. The easiest way to do this is to pass the query text as the runtime value.
NestedValueProvider could help you create the query string from another value provider, alas, NestedValueProvider only support one input ValueProvider at a time. So you could concatenate your start and end dates into a single value and then do the split.
I am trying to use the following method of building a table, as taken from the flatbuffers tutorial:
MonsterBuilder monster_builder(builder);
monster_builder.add_pos(&pos);
monster_builder.add_hp(hp);
But having done this for my root table I am unsure if I need to call .Finish() before adding it to the table that then contains the table above.
Is anyone able to provide me with an example of how usage of the add_member commands may be used in nested tables?
You call .Finish() on any tables you create with a table builder. You call .Finish(root) on your FlatBufferBuilder instance only once at the end to finish construction of the buffer.
I have two tables in different databases. In a table A is the data, in the other table B are information for incremental load of the data from the first table. I want to load from table B and store the date of the last successful load from table A in a mapping variable $$LOAD_DATE. To achieve this, I read a date from table B and use the SETVARIABLE() function in a expression to set the $$LOAD_DATE variable. The port in which I do this is marked as output and writes into a dummy flat file. I only read on row of this source!
Then I use this $$LOAD_DATE variable in the Source Filter of the Source Qualifier of table A to only load new records which are younger than the date stored in the $$LOAD_DATE variable.
My problem is that I am not able to set the $$LOAD_DATE variable correctly. It is always the date 1753-1-1-00.00.00, which is the default value for mapping variables of the type date/time.
How do I solve this? How can I store a date in that variable and use it later in a Source Qualifiers source filter? Is it even possible?
EDIT: Table A has too much records to read them all and filter them later. This would be to expensive, so they have to be filtered at source filter level.
Yes, it's possible.
In the first map you have to initialize the variable, like this:
In first session configuration you have to define the Post-session on success variable assignment:
The second map (with your table A) will get the variable after this configuration of the session in Pre-session variable assignment:
It will work.
It is not possible to set a mapping variable and use it's value somewhere else in the same run, because, the variable is actually set when the session completes.
If you really want to implement it using mapping variables you have to create two mappings, one for setting the mapping variable and another for actual incremental load. You can pass a mapping variable value from one session to another in a workflow using a workflow variable. https://stackoverflow.com/a/26849639/2626813
Other solutions could be to use a lookup on B and a filter after that.
You can also write some scripts to query table B and modify the parameter file with the latest $LOAD_DATE value prior to executing the mapping.
Since we're having two different DBs, use two sessions. Get values in the first one and pass the parameters to the second one.
What built-in routine can I make use of to cast data of type LVARCHAR to data of type TEXT?
The larger context: I have a table with a column that has been defined as LVARCHAR(4096). Now a developer wishes to change the data type of this column to TEXT. Ideally this would be done with:
ALTER TABLE foo MODIFY bar TEXT;
...but in such a case the following error is puked to the screen:
ALTER TABLE can not modify column (bar) type. Need a cast from the current type to the new type.
I have read up on the CREATE CAST construction, but I cannot begin to think what on earth the proper conversion function would look like. Without a function, Informix will not allow the CREATE CAST to work. That is, if I do, simply:
CREATE CAST (LVARCHAR AS TEXT)
...Informix tells me that a cast function is required (which makes sense).
Beware, Informix developers: if you inadvertently run into a problem like this, there is no way to get out of it using SQL or DDL alone. Let me repeat that.
If you have a VARCHAR or an LVARCHAR column that you need to migrate to be a TEXT column, and if you cannot afford to lose data in that column, there is no way to do this in SQL or DDL.
Instead, you must write a program that does the conversion for you inside the database driver, in memory. In my case, I used JDBC mutable result sets and copied the column to a new column, letting the JDBC driver perform the conversion, then dropped the old column, and renamed the new column back to the old column. This general pattern is the only way to migrate existing character data into a TEXT column.
#Storm: Which version of IDS/ODBC are you using? AFAIK, IDS 9 or 10 can't do that without using specific embedded C in server (See boulder site), but in no way you can do that directly through SQL. Blob related functions or so.
Othe way is by using UNLOAD / LOAD.
In my scenario, we have lots of problems: no admin rights to enterprise server, as we are service providers, we only can use database, but cannot modify structure. We cannot modify TEXT fields only by launching queries.