A method may comprise: receiving, by a front-end transaction central server, a browse request for browsing detailed information of a combined merchandise object, and acquiring stock information of each sub-merchandise object, respectively; if a target physical warehouse has a physical stock of at least one first sub-merchandise object and no physical stock of at least one second sub-merchandise object, and if a target virtual negative sale warehouse corresponding to the target physical warehouse has a virtual negative sale stock of the at least one second sub-merchandise object, providing salable information of the combined merchandise object; and when a request for buying the merchandise object is received, generating a transaction order, and determining the target physical warehouse as a prerouting warehouse of the first sub-merchandise object, and determining the target virtual negative sale warehouse as a prerouting warehouse of the second sub-merchandise object.