1. An information integrating apparatus comprising: a storage unit that stores therein meta-definitions that include physical models that are data models on an information source side, logical models that are data models on a user-side that uses integrated information, and a mapping definition indicating corresponding relations between a physical model and a logical model; an integrating unit that executes an integration process of referring to the meta-definition stored in the storage unit and integrating information from the physical model input from information sources and information from the logical model; a breaking up unit that executes a breaking up process of referring to the meta-definition stored in the storage unit and breaking up a query for the logical models into a query for the physical models respectively corresponding to the information sources; a collecting unit that executes a collection process of collecting information retrieved from the information sources via the query that is for the physical model and obtained at the breaking up unit; a detecting unit that detects a first instruction to integrate, by the integration process, information from the physical model, which is an information source to be integrated, and information from the logical model, and to return to the user-side, a first integration result, or detects a second instruction to execute the breaking up process on a query on the user side for the logical model, to execute the collection process with respect to a query that is for the physical model and obtained by the breaking up process, to integrate, by the integration process, the information from the physical model collected by the collection process and the information from the logical model, and to return to the user side, a second integration result; a control unit that controls the integrating unit to execute the integration process, if the detecting unit detects the first instruction and controls the breaking up unit, the collecting unit, and the integrating unit, and further executes the breaking up process on the query for the logical model on the user side, the collection process with respect to the query that is for the physical model and obtained by the breaking up process, and the integration process integrating the information from the physical model collected by the collection process, if the detecting unit detects the second instruction; and an output unit that outputs to the user-side, the first integration result obtained by control of the integrating unit, if the detecting unit detects the first instruction, and outputs to the user-side that has made the query, the second integration result obtained by control of the breaking up unit, the collecting unit, and the integrating unit, if the detecting unit detects the second instruction.