I have been trying to create indexing using below set of lines.
KeyspaceDefinition fromCluster = cluster.describeKeyspace(KEYSPACE);
ColumnFamilyDefinition cfDef = fromCluster.getCfDefs().get(0);
BasicColumnFamilyDefinition columnFamilyDefinition = newBasicColumnFamilyDefinition(cfDef);
BasicColumnDefinition columnDefinition = new BasicColumnDefinition();
columnDefinition.setName(StringSerializer.get().toByteBuffer("A_NO"));
columnDefinition.setIndexName("A_NO_idx");
columnDefinition.setIndexType(ColumnIndexType.KEYS);
columnDefinition.setValidationClass(ComparatorType.UTF8TYPE.getClassName());
columnFamilyDefinition.addColumnDefinition(columnDefinition);
But i am unable to do so. Actually i am storing the data in the columns dynamically as well as creating those columns dynamically and after that for better query purpose i am trying to put index on some particular columns. Any suggestion please how to do that.
Its eventually quite simple. You just have to create the secondary index while defining your columnfamily. In the above code, all the manipulation are done on the object index which has to be created while defining only. The steps for adding index are
List<ColumnDef> columns = new ArrayList<ColumnDef>();
columns.add(newIndexedColumnDef("columnName", "UTF8Type"));
List<ColumnDefinition> columnMetadata = ThriftColumnDef
.fromThriftList(columns);
cdefs.add(cf_def); //cf_def is your columnfamily definition
The helper method code is from KeyspaceCreationTest
public ColumnDef newIndexedColumnDef(String column_name, String comparer){
ColumnDef cd = new ColumnDef(se.toByteBuffer(column_name), comparer);
cd.setIndex_name(column_name);
cd.setIndex_type(IndexType.KEYS);
return cd;
}
References for comparer can be found here
I hope it will help you.
Related
I have several datasets. I would like to create a list for each one. Is there a way to do this in some kind of function? As of now I write it one below the other, since the code is quite long I don't want to do it manually for each dataset. I want to create a datasource list for each dataset, which contains the information of the respective dataset. As of now, my code looks like this:
datasource = df['Data_source'].tolist()
datasource1 = df1['Data_source'].tolist()
datasource2 = df2['Data_source'].tolist()
datasource3 = df3['Data_source'].tolist()
...
Thank you!
I'm a newbie so don't laugh :#
I'm working with 2002-2003 Microsoft access database.
Now, I want to add an array of DataRow into an existing table that I've in my database. Is there a way to do that? because right now I'm just adding the rows with a foreach loop
thank you
I think that the foreach-loop actually is the best way to do it.
foreach(DataRow row in yourRowArray)
{
dataTable.Add(row);
}
If you are using .Net Framework 3.5+ you can also use the DataRows CopyToDataTable() Method.
But you have to watch out because the Data in the DataTable is overwritten in this case.
DataTable table = yourDataTable;
DataRow[] yourRowArray = ...;
if(yourRowArray.Length > 0)
{
table = yourRowArray.CopyToDataTable();
}
I would recommend using the foreach-loop.
What you describe as array must be a saved file type i.e. excel or csv. Be sure it is a clean grid of data without extraneous non aligned rows.
Then you can link to that file with Access as a table. This is a manual step using the Access interface - in the ribbon it is the External area. This link remains good - allowing you to replace the excel/csv with a new one as long as the location path and structure of the file do not change.
Then you create an Append query to write all the records from this table into the table in your Access database.
www.CahabaData.com
So my Top-Level problem is I am trying to return whether a MERGE resulted in the creation of a new Node or not.
In order to do this I was thinking I could just create a simple temp boolean setting it to TRUE using ON CREATE
How I imagine it working:
MERGE(: Person {id:'Tom Jones'})
WITH false as temp_bool
ON CREATE set temp_bool = true
RETURN temp_bool
Obviously this does not work.
I am looking for a way to create arbitrary temp values within a Cypher query, and have the ability to return those variables in the end.
Thanks
You can do what you want, here's how (combination of my first answer, with #cybersam's addition). You just do it with a node property you create and then remove, instead of an unbound variable as you've been trying.
MERGE(tom:Person {id:'Tom Jones'})
ON CREATE set tom.temp_bool = true
ON MATCH set tom.temp_bool = false
WITH tom, tom.temp_bool AS result
REMOVE tom.temp_bool
RETURN result;
In simple merging cases like this where maximum one node could be created, a cleaner way to achieve what you are looking for could be checking the result stats. I case of using Bolt API you should check:
results.consume().counters.nodes_created = 1
It's been bugging me, I have a query which returns a single row and I need to get their corresponding column value.
//Retrieve Ticket Information to Database
$r = db_query("SELECT title, description, terms_cond, image, social_status, sched_stat FROM giveaway_table WHERE ticket_id = :ticket_id",
array(
':ticket_id' => $ticket_id
));
There are two ways that I can get data which is, by using fetchColumn() and fetchObject()
fetchObject()
$object = $r->fetchObject();
$ticket_info[] = $object->title;
$ticket_info[] = $object->description;
$ticket_info[] = $object->terms_cond;
$ticket_info[] = $object->image;
$ticket_info[] = $object->social_status;
$ticket_info[] = $object->sched_stat;
fetchColumn()
$title = $r->fetchColumn() //Returns title column value
$description = $r->fetchColumn(1) //Returns description column value
Was wondering, which one is better, or are there any pros and cons about this stuff?
if possible, can you guys also suggest the best way (if there's any) on how to retrieve all columns that's been selected in a query and store it into an array with less line of code.
There are two ways that I can get data which is, by using fetchColumn() and fetchObject()
really? what about fetch()?
There is a PDO tag wiki where you can find everything you need
I don't know pros and cons of using it. In my project I often used fetching as array rather than object. It was more comfortable. But if you make ORM projects then maybe it would be better to use fetchObject and make it your object not a std_class. You could make a contructor that has one parametr which is stdClass and make your object from this class
Answering your other question you can fetch all columns using fetchAll();
Follow this link to learn more about this function http://www.php.net/manual/en/pdostatement.fetchall.php
More about abstract database layer you can find here -> http://www.doctrine-project.org/
I need to find a way to get the newly insert row, without previously having to save to the database.
Is there a way? Or I need to keep the whole collection of row in a separated array?
Is this example I adding a row to the table tblConfig, but when I look back in the table the new row is not there.
tblConfig Config = new tblConfig { ID = Guid.NewGuid(), Code ="new config code" };
CTX.tblConfig.InsertOnSubmit(Config);
var Data = from dd in CTX.tblConfig select dd;
this.dataGridView1.DataSource = Data;
After some research , I'll do the work by attaching my LINQ query to a BindingSource object, witch will help me handle with insertion update and so.
Thanks for everyone, for your help :)
Hugo
Could you add that manually like this?
this.dataGridView1.DataSource = CTX.tblConfig.Execute(MergeOption.AppendOnly);