Yes, I realized the way to use CQL. I checked the way how map data is represented by using cassandra-cli. For each element in the map, it use the key as part of the column name and value as the column value. I just cannot insert this by using thrift API because I already defined a CompositeType column comparator. Is it a way to run a second program to insert map data with a different comparator?
Thanks. On Mon, Jun 23, 2014 at 10:21 AM, Sylvain Lebresne <sylv...@datastax.com> wrote: > On Mon, Jun 23, 2014 at 6:19 PM, James Campbell < > ja...@breachintelligence.com> wrote: > >> Huilang, >> >> >> Since there hasn't been another reply yet, I'll throw out an idea that >> worked for us as part of a test, though it does not seem exactly like a >> "preferred" way since it crosses code-bases. We built the type using >> straight java type, then used the Datastax v2 driver's DataType class >> serializer. >> >> >> Concretely, it would look like the following (adapting your code): >> >> Column column = new Column(); >> column.name=columnSerializer.toByteBuffer(colname); // the >> column name of the map type, it works with other kinds of data type >> >> ​column.value = DataType.map(DataType.ascii, >> DataType.decimal).serialize(yourMapGoesHere); >> column.timestamp = new Date().getTime(); >> >> ... >> > > This is exactly equivalent to what Huiliang posted and will thus not work > any better. > > Collections are internally not store as one "thrift column" per > collection. Each element of the collection is a separate "thrift column" > and the exact encoding depends on the collection. The fact is, updating CQL > collection from thrift is technically possible but it is not recommended in > any way. I strongly advise you to stick to CQL if you want to use CQL > collections. > > -- > Sylvain > >> >> >> ------------------------------ >> *From:* Huiliang Zhang <zhl...@gmail.com> >> *Sent:* Friday, June 20, 2014 10:10 PM >> *To:* user@cassandra.apache.org >> *Subject:* Use Cassnadra thrift API with collection type >> >> Hi, >> >> I have a problem when insert data of the map type into a cassandra >> table. I tried all kinds of MapSerializer to serialize the Map data and did >> not succeed. >> >> My code is like this: >> Column column = new Column(); >> column.name=columnSerializer.toByteBuffer(colname); // the >> column name of the map type, it works with other kinds of data type >> column.value = >> MapSerializer.getInstance(AsciiSerializer.instance, >> DecimalSerializer.instance).serialize(someMapData); >> column.timestamp = new Date().getTime(); >> >> Mutation mutation = new Mutation(); >> mutation.column_or_supercolumn = new ColumnOrSuperColumn(); >> mutation.column_or_supercolumn.column = column; >> mutationList.add(mutation); >> >> The data was input into the cassandra DB however it cannot be retrieved >> by CQL3 with the following error: >> ERROR 14:32:48,192 Exception in thread Thread[Thrift:4,5,main] >> java.lang.AssertionError >> at >> org.apache.cassandra.cql3.statements.ColumnGroupMap.getCollection(ColumnGroupMap.java:88) >> at >> org.apache.cassandra.cql3.statements.SelectStatement.getCollectionValue(SelectStatement.java:1185) >> at >> org.apache.cassandra.cql3.statements.SelectStatement.handleGroup(SelectStatement.java:1169) >> at >> org.apache.cassandra.cql3.statements.SelectStatement.processColumnFamily(SelectStatement.java:1076) >> ... >> >> So the question is how to write map data into cassandra by thrift API. >> Appreciated for any help. >> >> Thanks, >> Huiliang >> >> >> >> >
