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17.3. Operator get information from the SQL descriptor area

Lecture



  <get descriptor statement> :: =
    GET DESCRIPTOR <descriptor name>
   <get descriptor information>
 <get descriptor information> :: =
   <get count>
  (VALUE <item number>
   <get item information>
  ({<comma> <get item information>} ...]
 <get count> :: =
   <simple target specification 1>
   <equals operator> COUNT
 <get item information> :: =
   <simple target specification 2>
   <equals operator>
   <descriptor item name>
 <item number> :: = <simple value specification>
 <simple target specification 1> :: = <simple target specification>
 <simple target specification 2> :: = <simple target specification>
 <descriptor item name> :: =
    TYPE
  (LENGHT
  (OCTET_LENGHT
  (RETURNED_LENGHT
  (RETURNED_OCTET_LENGHT
  (PRECISION
  (SCALE
  (DATETIME_INTERVAL_CODE
  (DATATIME_INTERVAL_PRECISION
  (NULLABLE
  (INDICATOR
  (DATA
  (NAME
  (UNNAMED
  (COLLATION_CATALOG
  (COLLATION_SCHEMA
  (COLLATION_NAME
  (CHARACTER_SET_CATALOG
  (CHARACTER_SET_SCHEMA
  (CHARACTER_SET_NAME
 <simple target specification> :: =
   <parameter name>
 (<embedded variable name> 

Comment:

The GET DESCRIPTOR operator is used to select descriptive information previously placed in the descriptor using the DESCRIBE operator. For one execution of the operator, you can get either the number of filled elements of the descriptor (COUNT) or the information contained in one of the filled elements.


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IBM System R — реляционная СУБД

Terms: IBM System R — реляционная СУБД