При создании метаданных (таблицы, тригеры, домены и т.д.) мы можем получить ошибки которые будут не очень понятны начинающему пользователю

CREATE INDEX COUNTRY_IDX1 ON COUNTRY (CURRENCY);
CREATE INDEX COUNTRY_IDX1 ON COUNTRY (CURRENCY);

This operation is not defined for system tables.
unsuccessful metadata update.
STORE RDB$INDICES failed.
attempt to store duplicate value (visible to active transactions) in unique index «RDB$INDEX_5».

CREATE generator test;
CREATE generator test;

This operation is not defined for system tables.
unsuccessful metadata update.
DEFINE GENERATOR failed.
attempt to store duplicate value (visible to active transactions) in unique index «RDB$INDEX_11».

CREATE TABLE test(x INT, x VARCHAR(30));

This operation is not defined for system tables.
unsuccessful metadata update.
STORE RDB$RELATION_FIELDS failed.
attempt to store duplicate value (visible to active transactions) in unique index «RDB$INDEX_15».

CREATE PROCEDURE test (t INT) RETURNS (t VARCHAR(30))
AS 
BEGIN
END;

This operation is not defined for system tables.
unsuccessful metadata update.
STORE RDB$PROCEDURE_PARAMETERS failed.
attempt to store duplicate value (visible to active transactions) in unique index «RDB$INDEX_18».

CREATE DOMAIN test SMALLINT;
CREATE DOMAIN test SMALLINT;

This operation is not defined for system tables.
unsuccessful metadata update.
STORE RDB$FIELDS failed.
attempt to store duplicate value (visible to active transactions) in unique index «RDB$INDEX_2».

CREATE TRIGGER country_bi0 FOR country
active BEFORE INSERT POSITION 0
AS
BEGIN
  /* Trigger text */
END;
CREATE TRIGGER country_bi0 FOR country
active BEFORE INSERT POSITION 0
AS
BEGIN
  /* Trigger text */
END;

This operation is not defined for system tables.
unsuccessful metadata update.
DEFINE TRIGGER failed.
attempt to store duplicate value (visible to active transactions) in unique index «RDB$INDEX_8».