I am querying the Nhibernate criteria query with more then 2100 values for In clause.
I do something like Session.CreateCriteria(typeof()).Add(Expression.In("fieldName",arrayValue))
Where arrayValue contains more then 2100 values. I face error
Exception occurred:
UnknownError
NHibernate.ADOException: could not execute query ..then the query with more then 3000 values in array.
with some google help we found out that IN clause in Sql supports only till 2100 values.
Does anyone has faced similar issue earlier? We do not want to change the query as it is written in some generic way and not customized one.
This is a limitation of SQL Server. I wouldn't suggest doing this, but if you insist, you could work around it by creating a table-value sql function (see http://www.dzone.com/snippets/function-getting-comma) that splits up a string by commas (or whatever delimiter you want) and returns the values as a table, and then pass in all your ID's as (say) a comma separated list in 1 parameter and use a SQLCriterion in your criteria query.
eg:
criteria.Add(
new SQLCriterion("{alias}.ID IN (SELECT element FROM dbo.GetCSVValues(?))",
new[]{csvListOfIds},
new[]{NHibernateUtil.String}))
You could split the array into multiple batches, query multiple times, and then combine the result.
Related
First off this is my first attempt at a multi select. I've done a lot of searching but I can't find the answer that works for me.
I have a postgresql query which has bg.revision_key in (_revision_key) which holds the parameter. A side note, we've named all our parameters in the queries with the underscore and they all work, they are single select in SSRS.
In my SSRS report I have a parameter called Revision Key Segment which is the multi select parameter. I've ticked Allow multi value and in Available Values I have value field pointing to revision_key in the dataset.
In my dataset parameter options I have Parameter Value [#revision_key]
In my shared dataset I also have my parameter set to Allow multi value.
For some reason I can't seem to get the multi select to work so I must be missing something somewhere but I've ran out of ideas.
Unlike with SQL Server, when you connect to a database using an ODBC connection, the parameter support is different. You cannot use named parameters and instead have to use the ? syntax.
In order to accommodate multiple values you can concatenate them into a single string and use a like statement to search them. However, this is inefficient. Another approach is to use a function to split the values into an in-line table.
In PostgreSQL you can use an expression like this:
inner join (select CAST(regexp_split_to_table(?, ',') AS int) as filter) as my on my.filter = key_column
Then in the dataset properties, under the parameters tab, use an expression like this to concatenate the values:
=Join(Parameters!Keys.Value, ",")
In other words, the report is concatenating the values into a comma-separated list. The database is splitting them into a table of integers then inner joining on the values.
I am new to SQL and POSTGRES and had a quick question. Right now I have 2 different tables one with car info and one with partial car info and I would like to sort on car.vin OR partial_car.vin depending if either exists and sending all nulls/empty strings to the end of the sort. Currently my ORDER BY statement looks like:
ORDER BY nullif(coalesce(car.vin, partial_car.partial_vin), '') asc nulls last limit 50 offset 0
My expectation for this is that coalesce will take the first non null value and use that for sorting or it will return null and send that to the end. My results so far I haven't been able to make sense of. There are null values being placed in between actual values etc.. If I make this change coalesce(car.vin, '') again I see it work properly. Anyone have an ideas as to why this is the behavior? Let me know if you need something more from me.
It was human error on my end. The object being sent to client was not being populated properly with partial data. So sorting was correct but was seeing blanks due to those values not being present.
I have a class that contains a LINKMAP field called links. This class is used recursively to create arbitrary hierarchical groupings (something like the time-series example, but not with the fixed year/month/day structure).
A query like this:
select expand(links['2017'].links['07'].links['15'].links['10'].links) from data where key='AAA'
Returns the actual records contained in the last layer of "links". This works exactly as expected.
But a query like this (note the 10,11 in the second to last layer of "links"):
select expand(links['2017'].links['07'].links['15'].links['10','11'].links) from data where key='AAA'
Returns two rows of the last layer of "links" instead:
{"1000":"#23:0","1001":"#24:0","1002":"#23:1"}
{"1003":"#24:1","1004":"#23:2"}
Using unionAll or intersect (with or without UNWIND) results in this single record:
[{"1000":"#23:0","1001":"#24:0","1002":"#23:1"},{"1003":"#24:1","1004":"#23:2"}]
But nothing I've tried (including various attempts at "compound" SELECTs) will get the expand to work as it does with the original example (i.e. return the actual records represented in the last LINKMAP).
Is there a SQL syntax that will achieve this?
Note: Even this (slightly modified) example from the ODB docs does not result in a list of linked records:
select expand(records) from
(select unionAll(years['2017'].links['07'].links['15'].links['10'].links, years['2017'].links['07'].links['15'].links['11'].links) as records from data where key='AAA')
Ref: https://orientdb.com/docs/2.2/Time-series-use-case.html
I'm not sure of what you want to achieve, but I think it's worth trying with values():
select expand(links['2017'].links['07'].links['15'].links['10','11'].links.values()) from data where key='AAA'
I want to do something like this in OrmLite
SELECT *, COUNT(title) as titleCount from table1 group by title;
Is there any way to do this via QueryBuilder without the need for queryRaw?
The documentation states that the use of COUNT() and the like necessitates the use of selectRaw(). I hoped for a way around this - not having to write my SQL as strings is the main reason I chose to use ORMLite.
http://ormlite.com/docs/query-builder
selectRaw(String... columns):
Add raw columns or aggregate functions
(COUNT, MAX, ...) to the query. This will turn the query into
something only suitable for using as a raw query. This can be called
multiple times to add more columns to select. See section Issuing Raw
Queries.
Further information on the use of selectRaw() as I was attempting much the same thing:
Documentation states that if you use selectRaw() it will "turn the query into" one that is supposed to be called by queryRaw().
What it does not explain is that normally while multiple calls to selectColumns() or selectRaw() are valid (if you exclusively use one or the other),
use of selectRaw() after selectColumns() has a 'hidden' side-effect of wiping out any selectColumns() you called previously.
I believe that the ORMLite documentation for selectRaw() would be improved by a note that its use is not intended to be mixed with selectColumns().
QueryBuilder<EmailMessage, String> qb = emailDao.queryBuilder();
qb.selectColumns("emailAddress"); // This column is not selected due to later use of selectRaw()!
qb.selectRaw("COUNT (emailAddress)");
ORMLite examples are not as plentiful as I'd like, so here is a complete example of something that works:
QueryBuilder<EmailMessage, String> qb = emailDao.queryBuilder();
qb.selectRaw("emailAddress"); // This can also be done with a single call to selectRaw()
qb.selectRaw("COUNT (emailAddress)");
qb.groupBy("emailAddress");
GenericRawResults<String[]> rawResults = qb.queryRaw(); // Returns results with two columns
Is there any way to do this via QueryBuilder without the need for queryRaw(...)?
The short answer is no because ORMLite wouldn't know what to do with the extra count value. If you had a Table1 entity with a DAO definition, what field would the COUNT(title) go into? Raw queries give you the power to select various fields but then you need to process the results.
With the code right now (v5.1), you can define a custom RawRowMapper and then use the dao.getRawRowMapper() method to process the results for Table1 and tack on the titleCount field by hand.
I've got an idea how to accomplish this in a better way in ORMLite. I'll look into it.
The following works
s = select([tsr.c.kod]).where(tsr.c.rr=='10').group_by(tsr.c.kod)
and this does not:
s = select([tsr.c.kod, tsr.c.rr, any fields]).where(tsr.c.rr=='10').group_by(tsr.c.kod)
Why?
thx.
It doesn't work because the query isn't valid like that.
Every column needs to be in the group_by or needs an aggregate (i.e. max(), min(), whatever) according to the SQL standard. Most databases have always complied to this but there are a few exceptions.
MySQL has always been the odd one in this regard, within MySQL this behaviour depends on the ONLY_FULL_GROUP_BY setting: https://dev.mysql.com/doc/refman/8.0/en/group-by-handling.html
I would personally recommend setting the sql_mode setting to ANSI. That way you're largely compliant to the SQL standard which will help you in the future if you ever need to use (or migrate) to a standards compliant database such as PostgreSQL.
What you are trying to do is somehow valid in mysql, but invalid in standard sql, postgresql and common sense. When you group rows by 'kod', each row in a group has the same 'kod' value, but different values for 'rr' for example. With aggregate functions you can get some aspect of the values in this column for each group, for example
select kod, max(rr) from table group by kod
will give you list of 'kod's and the max of 'rr's in each group (by kod).
That being sad, in the select clause you can only put columns from the group by clause and/or aggregate functions from other columns. You can put whatever you like in where - this is used for filtering. You can also put additional 'having' clause after group that contains aggregate function expression that can also be used as post-group filtering.