DESCRIBE INDEX Statement

The DESCRIBE INDEX statement defines the specified index on a table.

Syntax

describe_index_statement ::=
    (DESCRIBE | DESC) [AS JSON] INDEX index_name ON table_name

Semantics

If you want the output to be in JSON format, you can specify the optional AS JSON.

The description for the index contains the following information:

• Name of the table on which the index is defined.
• Name of the index.
• Type of index. Whether the index is primary index or secondary index.
• Whether the index is multikey? If the index is multikey then 'Y' is displayed. Otherwise, 'N' is displayed.
• List of fields on which the index is defined.
• The declared type of the index.
• Description of the index.

Example 8-14

The following statement provides information about the index idx_income1 on the UserInfo table.

DESCRIBE AS JSON INDEX idx_income1 ON UserInfo
{  
   "name" : "idx_income1",
   "type" : "secondary", 
   "fields" : ["info.income"],  
   "types" : ["ANY_ATOMIC"],  
   "withNoNulls" : false,  
   "withUniqueKeysPerRow" : false
}

Example 8-15

The following statement provides information about the index idx_phones on the UserInfo table.

DESCRIBE AS JSON INDEX idx_phones ON UserInfo
{
  "name" : "idx_phones", 
  "type" : "secondary",  
  "fields" : ["info.phones[].number"],  
  "types" :  ["INTEGER"], 
  "withNoNulls" : false,  
  "withUniqueKeysPerRow" : true
}

Example 8-16

The following statement provides information about the index idx_modtime on the users table.

 DESCRIBE AS JSON INDEX idx_modtime ON users;
{
  "name" : "idx_modtime",
  "type" : "secondary",
  "fields" : ["modification_time#"],
  "withNoNulls" : false,
  "withUniqueKeysPerRow" : false
}

Example 8-17

The following statement provides information about the index idx_showid_year_month on the stream_acct table.

 DESCRIBE AS JSON INDEX idx_showid_year_month ON stream_acct;
{
  "name" : "idx_showid_year_month",
  "type" : "secondary",
  "fields" : ["acct_data.contentStreamed[].showId", "substring#acct_data.contentStreamed[].seriesInfo[].episodes[].date@,0,4", "substring#acct_data.contentStreamed[].seriesInfo[].episodes[].date@,5,2"],
  "types" : ["INTEGER", "STRING", "STRING"],
  "withNoNulls" : false,
  "withUniqueKeysPerRow" : false
}