Getting the frequency distribution of a column

Use the GET columnAnalysis/frequencyDistribution API command to get the frequency distribution of a column.

Command

GET columnAnalysis/frequencyDistribution

Parameters

projectName

The name of the project that contains the columns.

columnName

The name of the columns for which you want to retrieve the frequency distribution. The column name must be fully qualified; for example, HOST.DATASOURCE.SCHEMA.TABLE.COLUMN.. You can retrieve the frequency distributions of several columns in one operation by providing a comma-separated list of column names or by using wildcard characters. For example, host1.datasource1.schema1.table1.*, host1.datasource1.schema1.table2.* retrieves the distributions for all columns of tables table1 and table2 in schema1. And host_name1.datasource1.schema.*.* retrieves all distributions for all columns of all tables of schema1.

maxNbOfValues

The maximum number of values to retrieve. By default all values are retrieved

startIndex

The index is 1-based, meaning that 1 is the index of the first value. This option can be used by applications that present the values in pages and load one page at a time.

ordering

The sort order for the returned values. The value of the ordering parameter is one of the following options:

ascendingFrequencies
descendingFrequencies
ascendingValues
descendingValues

Available HTTP methods

Table 1. HTTP API for retrieving the frequency distribution of a column
HTTP method	URI pattern	DATA format	Success code	Error codes
GET	columnAnalysis/frequencyDistribution	XML	200	400 (bad request) or 500 (server error)

Example HTTP request and return value

The following example shows how to get the frequency distribution for column COL1 of the table TABLE1 of the schema SCHEMA1 of the data source SOURCE1 of the project project1 on the server myServer:

GET https://myServer:9443/ibm/iis/ia/api/columnAnalysis/frequencyDistribution
?projectName=project1&columnName=SOURCE1.SCHEMA1.TABLE1.COL1

The following example shows the return value:

<?xml version="1.0" encoding="UTF-8"?>
<iaapi:Project xmlns:iaapi="http://www.ibm.com/investigate/api/iaapi" 
   name="project1">
  <DataSources>
    <DataSource name="SOURCE1">
      <Schema name="SCHEMA1">
        <Table name="name="TABLE1">
          <Column name="COL1">
            <ColumnAnalysisResults>
              <FrequencyDistribution>
                <Terms>
                  <Term name="Category1/Term1"/>
                  <Term name="Category1/Term2"/>
                </Terms>
                <Value frequency="150" percent="0.15">0</Value>
                <Value frequency=”25” percent=”0.025”>Value1</Value>
                <Value frequency=”1” percent=”0.001”>Value2</Value>
                <Value frequency=”1” percent=”0.001”>Value3</Value>
                <Value frequency=”1” percent=”0.001”>Value4</Value>
                <Value frequency=”1” percent=”0.001”>Value5</Value>
                <Value frequency=”1” percent=”0.001”>Value6</Value>
                <Value frequency=”1” percent=”0.001”>Value7</Value>
                <Value frequency=”1” percent=”0.001”>Value8</Value>
                <Value frequency=”1” percent=”0.001”>Value9</Value>
                <Value frequency=”1” percent=”0.001”>Value10</Value>
                (...)
              </FrequencyDistribution>
            </ColumnAnalysisResults>
          </Column>
        </Table>
      </Schema>
    </DataSource>
  </DataSources>
</iaapi:Project>