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hbase

How to retrieve the records based on a condition from a Hbase table?

I have a Hbase table: employeedetails with column families:cols-personaldetails: firstname, lastname, professionaldetails: cols-company, empid and it has the following data in it.

 1    column=personaldetails:firstname, timestamp=1490959927100, value=Steven
 1    column=personaldetails:lastname, timestamp=1490959947478, value=Gerrard
 1    column=professionaldetails:company, timestamp=1490959968846, value=ABC
 1    column=professionaldetails:empid, timestamp=1490959978542, value=02429O
 2    column=personaldetails:firstname, timestamp=1490960007427, value=Sidhartha
 2    column=personaldetails:lastname, timestamp=1490960054615, value=Bobby
 2    column=professionaldetails:company, timestamp=1490960074243, value=DEF
 2    column=professionaldetails:empid, timestamp=1490960103882, value=02429N
 3    column=personaldetails:company, timestamp=1490960175772, value=WES
 3    column=personaldetails:empid, timestamp=1490960187863, value=987789
 3    column=personaldetails:firstname, timestamp=1490960128896, value=Sunny
 3    column=personaldetails:lastname, timestamp=1490960142031, value=Smith

Is there a way to write a command to retrieve the records whose first name starts with 'S'.

Solution

  • Use SingleColumnValueFilter

    This filter takes a column family, a qualifier, a compare operator and a comparator as arguments.

    1. If the specified column is not found, all the columns of that row will be emitted.
    2. If the column is found and the comparison with the comparator returns true, all the columns of the row will be emitted.
    3. If the column is found and the comparison with the comparator returns false, the row will not be emitted.

    Syntax:

    SingleColumnValueFilter (‘<family>’, ‘<qualifier>’, <compare operator>, ‘<comparator>’, <filterIfColumnMissing_boolean>, <latest_version_boolean>)

    Try:

    scan 'employeedetails' ,{ FILTER => "SingleColumnValueFilter('personaldetails','firstname',=, 'binaryprefix:S', true, false)" }

    If the filterIfColumnMissing flag is set to true, the columns of the row will not be emitted if the specified column to check is not found in the row.

    Let me know if this retrieves expected results.