Substring Search - Teradata Meta Data Services

Substring Search

Using the REGEX ComparisonOperator, character string properties can be searched for a match of a character string pattern within the property character string.

The following describes the search string value:

The search string value can be any character string.

The % and _ characters may be used in any combination in the search string

The % (percent sign) character represents any string of zero or more arbitrary characters.

The _ (spacing underscore) character represents exactly one arbitrary character.

Any single character is acceptable in the position in which the underscore character appears, and any string of characters is acceptable as a replacement for the percent.

The backslash character (\) can be used as an escape character to search for the %, _ or % characters ( \\, \%, \_ ) in the name or property value.

Both leading and trailing pad characters in the property field must match exactly with the search string. For example, ‘A%BC’ matches ‘AxxBC’, but not ‘AxxBΧD’, and ‘A%BΧD’ matches ‘AxxBΧD’, but not ‘AxxBC’ or ‘AxxBΧΔD’ (Δ indicates a pad character).

Example  

Using the following settings in a CMetaFilterInfo object:

      filterInfo.Filter.SetPropertyID(PID_NAME);

      filterInfo.Filter.SetString(_T(“%Pres%”));

      filterInfo.SetComparisonOperator(REGEX);

The MDS function will return objects with the following names:

      VicePresident

      President

      PresidentElect

      Elvis Presley

Example  

Changing the search string to:

      filterInfo.Filter.SetString(_T(“P%”));

The MDS function will return all objects with the names beginning with the character ‘P’:

      Peterson

      Powell

      Pruitt

Example  

Changing the search string to:

      filterInfo.Filter.SetString(_T(“_a%”));

Uses the % and _ characters to select a list of names with the letter A as the second letter in the name. The length of the name returned may be two or more characters. The function will return objects with the following names:

      Marston

      Watson

      Car

If the example used _a_, the search would be for a three-character string name with the letter a as the second character. In this case, the only object returned is:

      Car