chỉ có Tổng Giám đốc và thư ký văn phòng có truy cập vào nó. Khảo sát thông tin bao gồm: • • • • • Ngày: (2006/01/02) Người bán hàng của tên: (Harper, Paul) tên của người mua: (Smith, Joe) Các điểm đánh giá: lịch sự, chất lượng thông tin, vv Đối với mỗi điểm , dấu hiệu được đưa ra bởi người mua | Simpo PDF Merge and Split Unregistered Version - http Data Naming The free_value field itself must be defined with a generic field type like VARCHAR whose size must be wide enough to accommodate all values for all possible corresponding free_name values. It prevents easy validation for a weight we need a numeric value . Coding the SQL queries on these free fields becomes more complex - . SELECT internal_number from car_free_field where free_name weight and free_value 2000. Naming Recommendations Here we touch a subject that can become sensitive. Establishing a naming convention is not easily done because it can interfere with the psychology of the designers. Designer s Creativity Programmers and designers usually think of themselves as imaginative creative people UI design and data model are the areas in which they want to express those qualities. Since naming is writing they want to put a personal stamp to the column and table names. This is why working as a team for data structure design necessitates a good dose of humility and achieves good results only if everyone is a good team player. Also when looking at the work of others in this area there is a great temptation to improve the data elements names. Some discipline in the standardization has to be applied and all the team members have to collaborate. Abbreviations Probably because older database systems had severe restrictions about the representation of variables and data elements in general the practice of abbreviating has been taught for many years and is followed by many data structure designers and programmers. I used programming languages that accepted only two characters for variable names - we had to extensively comment the correspondence between those cropped variables and their meaning. Nowadays I see no valid reasons for systematically abbreviating all column and table names after all who will understand the meaning of your T1 table or your B7 field 34 Simpo PDF Merge and Split
