Remaps

The section looks at the limits encountered when creating remaps such as Decodes, Bands and Parametrics.

Numeric

Minimum no. of bands = 1

Maximum no. of bands = 254

It is not possible to sort by a numeric remap.

The Upper Bound of a Numeric remap Band is exclusive - i.e. values greater than or equal to the upper bound will not be included.

Records that do not fall into any of the specified bands, or are excluded by a filter will be banded as Null.

The source column for a numeric must come from the same table as the numeric banding and must be numeric.

Quantile

Minimum no. of bands = 1

Maximum no. of bands = 254

It is not possible to sort by a quantile remap.

The source column for a quantile must come from the same table as the quantile and must be numeric.

Records that do not fall into any of the specified bands, or are excluded by a filter will be banded as Null. It is not possible to include null values in the source column in any band other than the null band.

If the number of non-null and non-excluded records does not equally divide between the number of bands, the additional records will be placed in the first banding.

Parametric

There is no theoretical limit on the number of bins that can be added to a parametric remap. However, each bin creates a domain so there may be memory limits to take into consideration.

Parametric remaps cannot be used in aggregates or expressions and cannot be added to the column template of a domain.

It is not possible to sort by a parametric remap.

It is not possible to add parametric remaps to Multi-Dimensional Crosstabs.

It is not possible to un-index parametrics.

Decodes

The maximum number of decode dimensions that can be specified is 256,000.

If a decode contains more than 254 values, it will be stored as raw data and the following message will appear in the cerlog;

"Too Many Decode Values, Creating Real Data"

The memory for the decode will then be the memory required to store the decode labels as a text field.

For discrete values of less than 254, decodes require minimal storage.

The source column of the decode must come from the same table as the decode. It can be any data type.

It is not possible to un-index decodes.

A decode will always have a NULL value, even if there are no records in it. You should also provide a mapping for NULL values if you wish these to persist when specifying a Decode Remap. Failure to do this will mean that valid data with NULL values will be lost. It is possible to map null values in the source column to non-null values in the decoded column.

Decode columns are always created as TEXT columns - it is not possible to create a numeric decode.