The meaning and content of MRP
It means the product mix at all levels and the number of items of subordinate relationship to each item for the scheme object to the completion period of time for the benchmark inverted plan, according to early duration of the various articles distinction Issued the order in time plan, is a manufacturer of industrial enterprises in the materials management plan. MRP forecast is based on market demand and customer orders develop production plans, and then based on the product generated programming structure of the material composition of products table and inventory situation, the necessary materials by computer calculation of demand and needs time to determine the material the progress of the processing schedule and ordering a practical technology.

Its main contents include customer demand management, product plans, programs and raw materials inventory records. One customer demand management, including customer order management and sales forecasts, will be the actual customer orders and scientific customers demand forecasts that the combination can count out what customers need and how much demand.

The characteristics of MRP
1. The relevance of the demand: in circulation enterprises all needs are often independent. But in the production system, the demand is relevant. For example, under orders determine the amount of the required products, new product mix documents from the BOM to various projections to the number of parts and raw materials, which according to projections by the logic of relations between the quantity of materials known as the related demand. The numbers of species has not only relevant, demand and production process of time the decision is also relevant.

2. Demand certainty: MRP according to the needs of the main production schedule, product mix and inventory documents accurately calculated by the paper, variety, quantity and time requirements are strict requirements, irrevocable.

3. Complexity of plan: MRP plan according to the main production plan, the product structure document, paper stocks, production and procurement time to time, the main product of all.

Before the material needs of developing the basic data
Before the formulation of materials needs to be have the following basic data:
First Data is the main production plan, which specified time period should be in a plan to produce a variety of products and spare parts, it plans to formulate a demand for materials is one of the most important sources of data.
The second data is a list of materials (BOM), it pointed out the structure of relations between the material and the number of each type of material needs, it is material requirements planning system based on the data the most.
The third is the inventory data; it material to each of the existing stock of items and acceptance of the plan reflected the actual state.
Data is ahead of the fourth period, when the material is determined by each start, when completed.

It should be said that these four data are crucial, the one can not do. The lack of any one or any of the data is incomplete; the material needs of the development plan will be not accurate. Therefore, the demand for materials in the formulation of plans, these four data must first complete the establishment of good, but guaranteed