I'm trying to construct a JDOQL query (using datanucleus) that will search for matches of a parent class based on criteria in an owned one-to-many child class. The query looks like this:
Query lQ = lPm.newQuery("select from "+Module.class.getName()+
" where moduleMappings.contains(m)" +
" && showNameParam.matches(m.criteria.trim())");
lQ.declareVariables(ModuleMapping.class.getName()+" m");
lQ.declareParameters("String showNameParam");
lRet = (List<Module>) lQ.execute("StarTrek");
My data set looks something like this:
Module[1]
ModuleMapping[1]: criteria=".*"
Module[2]
ModuleMapping[1]: criteria=".*StarTrek.*"
ModuleMapping[2]: criteria=".*StarWars.*"
The query never matches on anything! However, if I replace the argument to the matches JDOQL method with a literal:
Query lQ = lPm.newQuery("select from "+Module.class.getName()+
" where moduleMappings.contains(m)" +
" && showNameParam.matches('.*StarTrek.*')");
Things will work for that single example, and my query will find Module[2]. What am I missing? Am I not allowed to use the contents of a mapped field as the argument to a JDOQL method? Do I need to escape things in some way?
Dave
So I figured this out, although to me it seems like a bug in either JDOQL or datanucleus. When using a mapped field as the argument to the matches method, the generated SQL does not translate the JDOQL syntax to the syntax of the data store (in my case, SQL). So in my example above, if I change the criteria fields to use SQL wildcard syntax rather than JDOQL syntax things will start to work.
Specifically, if in my example above I use criteria="%StarTrek%" rather than criteria=".\*StarTrek.\*" the JDOQL queries will start to match.
This doesn't seem right to me as different data stores could use different matching syntax, but this workaround gets me moving again...
The log would obviously tell you what SQL is being invoked for your query. You could also address why you are mixing API JDOQL and single-string JDOQL ... definition of parameters/variables should be in the single-string if using single-string.
Related
Using RODBCext (and Teradata) my SQL query often need to be restricted and is done so with a where statement. However, this is not always required and it would be beneficial to not restrict, but I would like to use a single SQL query. (The actual query is more complex and has several instances of what I'm attempting to apply here)
In order to return all rows, using a wildcard seems like the next best option, but nothing appears to work correctly. For example, the sql query is:
SELECT *
FROM MY_DB.MY_TABLE
WHERE PROC_TYPE = ?
The following does work when passing in a string for proc_type:
sqlExecute(connHandle, getSQL(SQL_script_path), proc_type, fetch = TRUE)
In order to essentially bypass this filter, I would like to pass a wildcard so all records are returned.
I've tried proc_type set to '%', '*'. Also escaped both with backslashes and enclosed with double-quotes, but no rows are ever returned, nor are any errors produced.
You could use COALESCE to do this:
SELECT *
FROM MY_DB.MY_TABLE
WHERE PROC_TYPE = COALESCE(?, PROC_TYPE);
In the event that your parameter is NULL it will choose PROC_TYPE to compare to PROC_TYPE which will return everything.
As for your wildcard attempt you would have to switch over to an operator that can use a wildcard. Instead of =, LIKE for instance. I think you would end up with some oddball edge cases though depending on your searchterm and the data in that column, so the COALESCE() option is a better way to go.
Is there any way to see what the SQL looks like after the parameters are resolved?
For example here is a small part of my SQL:
([Event].[Start_Time] LIKE #StartTimeValue)
And my parm:
SqlDataSourceObject.SelectParameters.Add("StartTimeValue", TypeCode.DateTime, StartTimeValue)
But what does the final SQL look like when the parm #StartTimeValue is replaced with the value in StartTimeValue?
How can I see that?
Thanks for your help.
Do you have access to the database server? From there you could run a tool like SQL Profiler.
Another way is to set a break point just before the query is executed and examine the variables that went in. Usually the issue lies somewhere with the variables you're passing in (they are null, etc) and not with the resolved query itself. You could also set it up in a SQL query window like so:
-- Declare the variable to be used.
DECLARE #StartTimeValue datetime;
-- Initialize the variable.
SET #StartTimeValue = '<PASTE VARIABLE VALUE YOU GOT FROM DEBUGGING HERE>';
SELECT * FROM [Event] WHERE ([Event].[Start_Time] LIKE #StartTimeValue);
I am trying to perform queries using the OR operator as following:
MapReduceResult result = riakClient.
mapReduce("some_bucket", "Name:c1 OR c2").
addMapPhase(new NamedJSFunction("Riak.mapValuesJson"), true).
execute();
I only get the 1st object in the query (where name='c1').
If I change the order of the query (i.e. Name:c2 OR c1) again I get only the first object in query (where name='c2').
is the OR operator (and other query operators) supported in the java client?
I got this answer from Basho engeneer, Sean C.:
You either need to group the terms or qualify both of them. Without a field identifier, the search query assumes that the default field is being searched. You can determine how the query will be interpreted by using the 'search-cmd explain' command. Here's two alternate ways to express your query:
Name:c1 OR Name:c2
Name:(c1 OR c2)
both options worked for me!
I'm looking for difference between ax query and select (or while select)
In this example i don't see what's i can not do with statement select : the example of ax query in msdn
I think I misunderstood the syntax of ax query ranges :'(
A (while) select is a 'one use' statement, ie, you put it inline in your code and it is used only there.
A query can be setup to require parameters and can be used multiple times throughout your class or saved into the AOT for use in any class.
Generally I only use select statements for simple queries where its not worth the effort to create a query, for anything more complex I use queries.
I get the following error:
Cannot use empty object or column names. Use a single space if necessary.
Msg 1038, Level 15, State 3, Line 1
and the query command looks like:
SELECT TOP 100 PERCENT
[].[cms_page].[pa_id], [].[cms_page].[pa_key],
[].[cms_page].[pa_title], [].[cms_page].[pa_keywords],
[].[cms_page].[pa_description], [].[cms_page].[pa_header],
[].[cms_page].[pa_created], [].[cms_page].[pa_modified],
[].[cms_page].[pa_language] FROM [cms_page]
WHERE
[cms_page].[pa_key] = #pa_key0
ORDER BY
[pa_id] ASC;
Strange indeed. Why does this happen? I'm using SubSonic 2.1.
Connectionstring:
<add name="OCDB" connectionString="Network Library=DBMSSOCN;Data Source=127.0.0.1,1433;Initial Catalog=test_db;User ID=test;Password=testpwd"/>
Edit: Well the solution was just to simply generate and rebuild the Data Access Layer and I was good to go.
You seem to be using a 3 part name with part of it empty, i.e. '[].'
It looks as though the query text is being constructed with an empty table schema.
Those empty [] square brackets should contain something like "dbo" to make the query syntactically valid. I don't know enough about SubSonic to give you a code sample though.
I'm not familiar with SubSonic, but have you tried a simpler query to test if you have your syntax correct? Does this query even work in SQL Server (Management Studio / Query Analyzer)?
Just looking at this from the perspective of SQL Server, you are using way too many brackets. If I was writing that query in SQL Server, it would look more like what I wrote below. I'm not sure about the variable #pa_key0, is this query part of a stored procedure or does SunSonic replace this variable when the query is ran?
SELECT
pa_id,
pa_key,
pa_title,
pa_keywords,
pa_description,
pa_header,
pa_created,
pa_modified,
pa_language
FROM
cms_page
WHERE
pa_key = #pa_key0
ORDER BY
pa_id ASC;
I think you need to set the schema for Subsonic to use. This thread seems to have some information:
Subsonic - How to use SQL Schema / Owner name as part of the namespace?