以下这个sql是在什么情况下触发的
SELECT NULL AS TABLE_CAT, T.OWNER AS TABLE_SCHEM, T.TABLE_NAME AS TABLE_NAME, T.COLUMN_NAME AS COLUMN_NAME, DECODE(SUBSTR(T.DATA_TYPE, 1, 9), 'TIMESTAMP', DECODE(SUBSTR(T.DATA_TYPE, 10, 1), '(', DECODE(SUBSTR(T.DATA_TYPE, 19, 5), 'LOCAL', -102, 'TIME ', -101, 93), DECODE(SUBSTR(T.DATA_TYPE, 16, 5), 'LOCAL', -102, 'TIME ', -101, 93)), 'INTERVAL ', DECODE(SUBSTR(T.DATA_TYPE, 10, 3), 'DAY', -104, 'YEA', -103), DECODE(T.DATA_TYPE, 'BINARY_DOUBLE', 101, 'BINARY_FLOAT', 100, 'BFILE', -13, 'BLOB', 2004, 'CHAR', 1, 'CLOB', 2005, 'COLLECTION', 2003, 'DATE', 93, 'FLOAT', 6, 'LONG', -1, 'LONG RAW', -4, 'NCHAR', -15, 'NCLOB', 2011, 'NUMBER', 2, 'NVARCHAR', -9, 'NVARCHAR2', -9, 'OBJECT', 2002, 'OPAQUE/XMLTYPE', 2009, 'RAW', -3, 'REF', 2006, 'ROWID', -8, 'SQLXML', 2009, 'UROWID', -8, 'VARCHAR2', 12, 'VARRAY', 2003, 'XMLTYPE', 2009, DECODE((SELECT A.TYPECODE FROM ALL_TYPES A WHERE A.TYPE_NAME = T.DATA_TYPE AND ((A.OWNER IS NULL AND T.DATA_TYPE_OWNER IS NULL) OR (A.OWNER = T.DATA_TYPE_OWNER)) ), 'OBJECT', 2002, 'COLLECTION', 2003, 1111))) AS DATA_TYPE, T.DATA_TYPE AS TYPE_NAME, DECODE (T.DATA_PRECISION, NULL, DECODE(T.DATA_TYPE, 'NUMBER', DECODE(T.DATA_SCALE, NULL, 0 , 38), DECODE (T.DATA_TYPE, 'CHAR', T.CHAR_LENGTH, 'VARCHAR', T.CHAR_LENGTH, 'VARCHAR2', T.CHAR_LENGTH, 'NVARCHAR2', T.CHAR_LENGTH, 'NCHAR', T.CHAR_LENGTH, 'NUMBER', 0, T.DATA_LENGTH) ), T.DATA_PRECISION) AS COLUMN_SIZE, 0 AS BUFFER_LENGTH, DECODE (T.DATA_TYPE, 'NUMBER', DECODE(T.DATA_PRECISION, NULL, DECODE(T.DATA_SCALE, NULL, -127 , T.DATA_SCALE), T.DATA_SCALE), T.DATA_SCALE) AS DECIMAL_DIGITS, 10 AS NUM_PREC_RADIX, DECODE (T.NULLABLE, 'N', 0, 1) AS NULLABLE, NULL AS REMARKS, T.DATA_DEFAULT AS COLUMN_DEF, 0 AS SQL_DATA_TYPE, 0 AS SQL_DATETIME_SUB, T.DATA_LENGTH AS CHAR_OCTET_LENGTH, T.COLUMN_ID AS ORDINAL_POSITION, DECODE (T.NULLABLE, 'N', 'NO', 'YES') AS IS_NULLABLE, NULL AS SCOPE_CATALOG, NULL AS SCOPE_SCHEMA, NULL AS SCOPE_TABLE, NULL AS SOURCE_DATA_TYPE, 'NO' AS IS_AUTOINCREMENT, T.VIRTUAL_COLUMN AS IS_GENERATEDCOLUMN FROM ALL_TAB_COLS T WHERE T.OWNER LIKE :B3 ESCAPE '/' AND T.TABLE_NAME LIKE :B2 ESCAPE '/' AND T.COLUMN_NAME LIKE :B1 ESCAPE '/' AND T.USER_GENERATED = 'YES' ORDER BY TABLE_SCHEM, TABLE_NAME, ORDINAL_POSITION