发表日期: 2022-11-28 16:59:20 浏览次数:40
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功能属性代币的使用场景与众筹模式有高度相似之处。就众筹模式而言,其依托实际的服务场景或具象的产品,消费者以折扣价格提前获得一个产品或者服务在未来的拥有权或使用权,对项目方而言将营销前置,在产品或服务未完成时获得订单,从消费者中获得变向融资以促成产品或服务的完成,消费者也就成为投资者,合二为一。
当一个产品或服务单位被通证化,而后被分割为颗粒度更细可流转的加密权证时,
这样的代币通常被划分为功能属性代币。 与众筹不同的是,这些加密权证在从一级市场获得后(从项目方购买)可以在二级市场流转(加密资产交易所交易)。
CREATE FUNCTION trigf() RETURNS trigger AS 'filename' LANGUAGE C; CREATE TRIGGER tbefore BEFORE INSERT OR UPDATE OR DELETE ON ttest FOR EACH ROW EXECUTE PROCEDURE trigf(); CREATE TRIGGER tafter AFTER INSERT OR UPDATE OR DELETE ON ttest FOR EACH ROW EXECUTE PROCEDURE trigf();
现在你可以测试该触发器的操作:
=> INSERT INTO ttest VALUES (NULL); INFO: trigf (fired before): there are 0 rows in ttest INSERT 0 0 -- Insertion skipped and AFTER trigger is not fired => SELECT * FROM ttest; x --- (0 rows) => INSERT INTO ttest VALUES (1); INFO: trigf (fired before): there are 0 rows in ttest INFO: trigf (fired after ): there are 1 rows in ttest ^^^^^^^^ remember what we said about visibility. INSERT 167793 1 vac=> SELECT * FROM ttest; x --- 1 (1 row) => INSERT INTO ttest SELECT x * 2 FROM ttest; INFO: trigf (fired before): there are 1 rows in ttest INFO: trigf (fired after ): there are 2 rows in ttest ^^^^^^ remember what we said about visibility. INSERT 167794 1 => SELECT * FROM ttest; x --- 1 2 (2 rows) => UPDATE ttest SET x = NULL WHERE x = 2; INFO: trigf (fired before): there are 2 rows in ttest UPDATE 0 => UPDATE ttest SET x = 4 WHERE x = 2; INFO: trigf (fired before): there are 2 rows in ttest INFO: trigf (fired after ): there are 2 rows in ttest UPDATE 1 vac=> SELECT * FROM ttest; x --- 1 4 (2 rows) => DELETE FROM ttest; INFO: trigf (fired before): there are 2 rows in ttest INFO: trigf (fired before): there are 1 rows in ttest INFO: trigf (fired after ): there are 0 rows in ttest INFO: trigf (fired after ): there are 0 rows in ttest ^^^^^^ remember what we said about visibility. DELETE 2 => SELECT * FROM ttest; x --- (0 rows)
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