cassandra: query with index expression doesn't work - indexing

I'm trying to get data from Cassandra with this query:
$cf=new ColumnFamily($data->cp,'ips');
$index[]=CassandraUtil::create_index_expression('c',1,'EQ');
$index[]=CassandraUtil::create_index_expression('begin_ip',1599147740,'GTE');
$index[]=CassandraUtil::create_index_expression('end_ip',1599147740,'LTE');
$index_clause = CassandraUtil::create_index_clause($index);
$rows=$cf->get_indexed_slices($index_clause);
foreach($rows AS $key=>$row)
{
$result[]=$row;
}
var_dump($result);
But the result is null.
I'm definitely sure that there is a row in cf ips which absolutely answers this query.
Validation class for all columns is IntegerType.
In cassandra-cli the equal query:
get ips where c = int('1') and
begin_ip <= int('1599147740') and
end_ip >= int('1599147740');
also gets null.
What am I doing wrong?

First, have you created an index on the 'c' column?
Second, you'll need to use 'cassandra_IndexOperator::EQ' and similar for the expression operator instead of a string.

Related

Add conditions where with 2 field conditions do not run accurately

The data that appears does not match the conditions that have been applied
I implemented SQL code in the Navicat application, and have changed the structure of the code several times but it still doesn't work,
data that is not of ilart condition type
still appears
SELECT SERMAT,ILART,sum(GKSTP) as jumlah
FROM swift_zab_iw39
WHERE ILART='OVH' OR ILART='TST' and SERMAT='024147-000:09052'
GROUP BY ILART,SERMAT
Use IN operator:
WHERE ILART IN('OVH','TST') AND SERMAT = '024147-000:09052'
Add parenthesis to the OR condition in the WHERE clause as:
WHERE (ILART = 'OVH' OR ILART = 'TST') AND SERMAT = '024147-000:09052'

PostgreSQL conditional where clause

In my Ruby on Rails app I'm using blazer(https://github.com/ankane/blazer) and I have the following sql query:
SELECT *
FROM survey_results sr
LEFT JOIN clients c ON c.id = sr.client_id
WHERE sr.client_id = {client_id}
This query works really well. But I need to add conditional logic to check if client_id variable is present. If yes then I filter by this variable, if not then I not launching this where clause. How can I do it in PostgreSQL?
Check if its null OR your condition like this:
WHERE {client_id} IS NULL OR sr.client_id = {client_id}
The WHERE clause evaluate as follow: If the variable is empty, then the WHERE clause evaluate to true, and therefore - no filter. If not, it continue to the next condition of the OR
If anyone faced with the psql operator does not exist: bigint = bytea issue, here is my workaround:
WHERE ({client_id} < 0 AND sr.client_id > {client_id}) OR sr.client_id = {client_id}
Please consider that, client_id generally cannot be negative so you can use that information for eleminating the operation cast issue.
My solution:
I use spring data jpa, native query.
Here is my repository interface signature.
#Query(... where (case when 0 in :itemIds then true else i.id in :itemIds end) ...)
List<Item> getItems(#Param("itemIds) List<Long> itemIds)
Prior calling this method, I check if itemIds is null. If yes, I set value to 0L:
if(itemIds == null) {
itemIds = new ArrayList<Long>();
itemIds.add(0L);
}
itemRepo.getItems(itemIds);
My IDs starts from 1 so there is no case when ID = 0.

Linq Query in VB

Good Day,
I am querying my database using Linq and I have run into a problem, the query searched a column for a search phrase and based on if the column has the phrase, it then returns the results, The query is below,
Dim pdb = New ProductDataContext()
Dim query =
From a In pdb.tblUSSeries
Join b In pdb.tblSizes_ On a.Series Equals b.Series
Where
a.Series.ToString().Equals(searchString) Or
b.Description.Contains(searchString) Or Not b.Description.Contains(Nothing)
Order By b.Series, b.OrderCode Ascending
Select New CustomSearch With
{
.Series = a.Series,
.SeriesDescription= a.Description,
.Coolant = a.Coolant,
.Material = a.Material,
.Standard = a.Standard,
.Surface = a.Surface,
.Type = a.Type,
.PointAngle = a.PointAngle,
.DiaRange = a.DiaRange,
.Shank = b.Shank,
.Flutes = b.Flutes,
.EDPNum = b.EDPNum,
.SizesDescription = b.Description,
.OrderCode = b.OrderCode
}
Return query
I think the problem is that, in the table certain rows are NULL, so when it is checking the column for the phrase and it encounters a row that is null it, breaks and returns this error,
The cast to value type 'System.Int32' failed because the materialized value is null. Either the result type's generic parameter or the query must use a nullable type.
I have ran this query against another column that has all the rows populated with data and it returns the results ok.
So my question is how can I write it in VB to query the db with the supplied searchstring and return the results, when some of the rows in the columns have null values.
Any help would be great.
The exception occurs when you make the projection (i.e. select new CustomSearch)
And yes your trying to assign Null to some int property
(Not sure which one of your properties that is)
one of 2 choices :
1) Use nullalbe types for your properties (or just that one property).
2) project with an inline If ( ?? in C#) , I don't know VB so don't catch me on the syntax.
Taking Series just as an example i don't know if it's an int or if that's the problematic property
Select New CustomSearch With
{
.Series = If(a.Series Is Nothing,0, CInt(a.Series))
}
In C#
Select new CustomSearch
{
Series = a.Series ?? 0;
}

'Where' Query in Rails

I have a table Order(:id, :number). I need to find count of those records from Order whose column(:number) value is not -1(default). I wrote :
Order.where(:number != -1).count
But this gives the value Order.count still. What is wrong?
You don't pass arguments to where properly. In this case, you should pass it as string:
Order.where('numer != ?', -1).count
or use not:
Order.where.not(number: -1).count

SQL regex and field

I want to change the query to return multiply values in extra_fields, how can I change the regex? Also I don't understand what extra_fields is - is it a field? If so why it is not called with the table prefix like i.extra_fields?
SELECT i.*,
CASE WHEN i.modified = 0 THEN i.created ELSE i.modified END AS lastChanged,
c.name AS categoryname,
c.id AS categoryid,
c.alias AS categoryalias,
c.params AS categoryparams
FROM #__k2_items AS i
LEFT JOIN #__k2_categories AS c ON c.id = i.catid
WHERE i.published = 1
AND i.access IN(1,1)
AND i.trash = 0
AND c.published = 1
AND c.access IN(1,1)
AND c.trash = 0
AND (i.publish_up = '0000-00-00 00:00:00'
OR i.publish_up <= '2013-06-12 22:45:19'
)
AND (i.publish_down = '0000-00-00 00:00:00'
OR i.publish_down >= '2013-06-12 22:45:19'
)
AND extra_fields REGEXP BINARY '(.*{"id":"2","value":\["[^\"]*1[^\"]*","[^\"]*2[^\"]*","[^\"]*3[^\"]*"\]}.*)'
ORDER BY i.id DESC
The extra_fields is a column of the #__k2_items table. The table qualifier can be omitted, because it is not ambiguous in this query. The column is JSON encoded. That is a serialization format used to store information which is not searchable by design. Applying a RegExp may work one day, but fail another day, since there is no guarantee for id preceeding value (as in your example).
The right way
The right way to filter this is to ignore the extra_fields condition in the SQL query an evaluate in the resultset instead. Example:
$rows = $db->loadObjectList('id');
foreach ($rows as $id => $row) {
$extra_fields = json_decode($row->extra_fields);
if ($extra_fields->id != 2) {
unset($rows[$id]);
}
}
The short way
If you can't change the database layout (which is true for extensions you want to keep updateable), you must split the condition into two, because there is no guarantee for a certain order of the subfields. For some reason, one day value may occur before id. So change your query to
...
AND extra_fields LIKE '%"id":"2"%'
AND extra_fields REGEXP BINARY '"value":\[("[^\"]*[123][^\"]*",?)+\]'
Prepare an intermediate table to hold the contents of extra_fields. Each extra_fields field will be converted into a series of records. Then do a join.
Create a trigger and cronjob to keep the temp table in sync.
Another way is to write UDF in Perl that will decode the field, but AFAIK it is not indexable in mysql.
Using an external search engine is out of scope.
Ok, i didnt want to change the db strucure, i gost some help and changed the regex intoAND extra_fields REGEXP BINARY '(.*{"id":"2","value":\[("[^\"]*[123][^\"]*",?)+\]}.*)'
and i got the right resaults
Thanks