Enhance cassandra-cli with more flexible querying and better data type support
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Key: CASSANDRA-1688
URL: https://issues.apache.org/jira/browse/CASSANDRA-1688
Project: Cassandra
Issue Type: Improvement
Components: Tools
Reporter: Jim Ancona
In trying to use cassandra-cli, I've felt the need to have better support for
non-String data types, and more flexibility in the types of queries possible.
The attached patch is an attempt to address some of those issues.
It enhances the GET command with a more flexible syntax, outlined below. The
new syntax adds to and partially duplicates the current GET syntax, but is more
verbose. Functionally it's a superset of the LIST command, but I haven't
removed any functionality yet. I added support for the Thrift getSlice and
getRangeSlices calls.
Syntax overview:
getSlice examples:
{noformat}
get CF2 key Long(12345) columns from 10000 to 99999999999
get SCF1 supercolumn 'super' key 'hello' columns 'world' as integer, 'moon' as
ascii,
{noformat}
getRangeSlices examples:
{noformat}
get CF2 keys all columns from 10000 to 99999999999
get SCF1 supercolumn 'super' keys from Integer(1234567876) limit 500 columns
'world' as integer
get CF2 keys from 'A' to 'Z' columns from 10000 to 99999999999 limit 50
{noformat}
Pseudo-Antlr syntax
{noformat}
thriftGetSlice
: K_GET columnParent 'KEY' keyValue columnSlice?
thriftGetRangeSlices
: K_GET columnParent keyRange? columnSlice?
columnParent
: columnFamily ('SUPERCOLUMN' superColumnName)?
columnSlice
: (columnList | columnRange | allColumns)
columnList
: 'COLUMNS' columnSpec (',' columnSpec)*
columnRange
: 'COLUMNS' ('FROM' startColumn)? ('TO' endColumn)? ('AS' typeIdentifier)?
('LIMIT' limit)?
allColumns
: 'COLUMNS' 'ALL' ('AS' typeIdentifier)? ('LIMIT' limit)?
keyRange
: 'KEYS' ( ('FROM' startKeyValue)? ('TO' endKeyValue)? | ALL ) ('LIMIT'
limit=IntegerLiteral)?
columnSpec
: columnName ('AS' typeIdentifier)?
value: (Identifier | IntegerLiteral | StringLiteral | functionCall );
functionCall
: functionName=Identifier '(' functionArgument ')'
{noformat}
Questions:
* Should I use a different keyword? Perhaps GET should be reserved for the
simple bracket-based, single-key case and this functionality should use LIST or
SELECT as a keyword.
* Should the syntax be more SQL-like? I started out doing that, but it seemed
to me that the C* model is so different that mapping it to the SQL syntax was
difficult. I haven't looked at Eric Evans' CQL work in any detail yet, but
perhaps that is a better model.
Additional work:
* The KEYS and COLUMNS keywords should be added to the GET / WHERE syntax for
getIndexedSlices.
* The LIST command should be deprecated or removed.
* The SET command should be enhanced to allow for non-string keys and column
names.
* I've used a different model for processing the syntax tree in the code. If
other people like it, it would make sense to convert the rest of CliClient to
the same model.
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