CREATE TABLE IF NOT EXISTS "sequences"
(
    "key"         VARCHAR(64) NOT NULL,
    "type"        VARCHAR(64) NOT NULL,
    "seq"         BIGINT      NOT NULL,
    "update_time" TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    PRIMARY KEY ("key", "type")
);
COMMENT ON TABLE "sequences" IS '当前序号表';
COMMENT ON COLUMN "sequences"."key" IS '序号英文名称';
COMMENT ON COLUMN "sequences"."type" IS '序号类型';
COMMENT ON COLUMN "sequences"."seq" IS '已使用到的序号';
COMMENT ON COLUMN "sequences"."update_time" IS '最后使用时间';