[Reconstruction of individual data centers]-create a database trilogy and a data center Trilogy

[Reconstruction of individual data centers]-create a database trilogy and a data center Trilogy

After edification of the basic three-layer idea, we will immediately enterReconstruction of personal IDCI feel like I am a cainiao, and I have a long way to go. To build high-rise buildings, there must be cement and bricks and tiles. The database is the container for managing data resources. The following is the process for creating tables by myself. If anything is wrong, please correct me!

I. Three paradigms

Benefits:Relational Database specifications, in order to reduce data redundancy. Satisfying the three paradigms indicates that the database is sound, data redundancy is low, and later maintenance is convenient.

Details:

1NF ):Fields in the database table are single attributes and cannot be divided, ensuring the atomicity of each column.

For example:AddressSplitProvince and city, Until it cannot be split.

2NF ):Upgrade of the first paradigm ~ The goal is to ensure that each column in the table is related to the primary key.

For example, to design a student exam detail table (table 1), the joint primary key is the student ID and course. The student ID is used as the primary key, and credits are only related to the course. This violates the design principles of the second paradigm.

Therefore, in this case, we should split the table andStudent InformationTo a table (table 2.0 ),Course informationDetach to another table (2.2 ).

What will happen if you do not split it?

Data redundancy:If one student chooses n courses, the student information will be repeated n-1 times (Area 1 in Table 3 is where data is redundant), and n students will take one course, the course and credits will also be repeated for n-1 times.

Update exception:If you need to update the credits of a course, all credits in the table must be updated. Otherwise, different credits may occur for the same course.

If a course is added, no student is required to take the course, and no primary key is required: Student ID, the course information cannot be stored in the database.

Deletion exception:If a group of students graduate, the score record will be deleted, and the course name and credits will be deleted. If it is difficult to wait until the school starts, a group of new students will be filled in ???

3NF ):On the basis of the second paradigm, we will go further into a layer. Make sure that each column is directly related to the primary key column, rather than indirectly related.

For example, a table of student information (table 4) has a deciding relation: Student ID --> name, age, and gender. The following deciding relation exists:

Student ID --> card number --> balance, status, with the balance, status of the student ID transfer dependency, is indirectly related. It violates the principles of the third paradigm.

Therefore, it is perfect to split it into tables 5 and 6!

Of course, the third paradigm also has data redundancy, update exceptions, and deletion exceptions. Details are similar to those of the second paradigm.

2. Analysis Tool of "E-R diagram"

E-R (Enitity Relationship divisor): provides a way to represent entities, associations, and properties, used to describe the conceptual model of the macro world.

This is the E-R graph I drew. The process of drawing is a process of Clarifying Ideas. At the beginning, the recharge, refund, and other tables are only used to know that a table contains information such as the card number and operator ID. At that time, I still thought the ID was redundant, but now I found that it and the card number form a joint primary key, which plays a significant role ~

Iii. Implementing "SQL Tabulation"I personally feel that it is not difficult to create a table in this place. Pay attention to the following points:
1. Why are naming rules required?There are no rules that are not square. Naming is an embodiment of professional quality, and standardized naming is also easy for us to modify and maintain later.
2. Is the data type char or varchar?Char is a fixed length. When the input character is smaller than the specified number, char (8) and the input character is smaller than 8, it will fill in a null value later. If the value is greater than 8, extra characters are truncated. Varchar is a variable-length, non-Unicode character data with a length of n Bytes. N is a value between 1. Saves storage space. Because char has a fixed length, the processing speed is much faster than that of varchar, but it is relatively free of storage space. Therefore, it is not suitable for storage, but char type can be used for speed requirements, otherwise, you can use varchar.
Select an appropriate data type for other fields. Not all fields must be of the char type.
3. What should I do if I cannot modify fields after creating a table?In SQL Server, the field name cannot be modified or added to the new table. You can choose tools> Options> Designers> Table Designer and Database Designer from the menu to remove the check box.




4. Summary every time we get to the end, we need to draw a little bit of our own feelings to record my commitment to the computer industry (here we should have a round of applause O ~). My biggest feeling of table creation is: 1. Don't be afraid to know, don't be afraid to know. Three paradigm, E-R map has not been well studied at the beginning, just know that it has a great use for table creation. Although I don't know, I can learn it right away when I use it, saving a lot of time for detours. 2. Write your own things. It's a big headache ~ What others say is better. If you write a blog as you do, you may be impressed. 3. Time management is really a life-saving Bodhisattva! Since being forced by the teacher, I have carefully studied management for a few days and found that my head does not hurt, my eyes are not spent, and the officers have a focus. I feel very fulfilled and happy every day. Just a few days ago, I felt pretty good. Stick to it. The little rookie will surely be a big bird one day ~

　　
Network protocols required for building the IDC

Hello. ASKER. What you are talking about is the IDC construction standard.

National standards: design specifications for electronic computer room
Chapter 1 General Provisions
Article 1.0.1 in order to ensure the stable and reliable operation of the electronic computer system and ensure a good working environment for the staff of the electronic computer room, the electronic computer room shall be advanced in technology, economically reasonable, safe and applicable, and ensure quality, this provision is formulated.

Article 1.0.2 this provision applies to the design of an electronic computer room with a construction area greater than or equal to 140 square m of the Master Data room for new, reconstructed, and expanded buildings on land. This provision does not apply to computer rooms and Micro-Computer Rooms for industrial control purposes.
Article 1.0.3 the design of an electronic computer room shall comply with the provisions of the relevant national standards and regulations in addition to the provisions of this provision.

Chapter ii idc location and Equipment Layout
Section 1 Location Selection of an electronic computer room
Article 2.1.1 the electronic computer room shall be located on the second and third floors in multi-storey buildings or high-rise buildings.
Article 2.1.2 the location of an electronic computer room shall meet the following requirements:
I. adequate water supply, stable and reliable electronics, convenient transportation and communication, and clean natural environments;
2. Stay away from factories, warehouses, and yards that produce dust, oil fume, harmful gases, and produce or store corrosive, inflammable, and explosive materials;
3. Stay away from strong vibration sources and strong noise sources;
4. Avoid interference from strong electromagnetic fields.
Article 2.1.3 effective electromagnetic shielding measures can be taken when strong electromagnetic interference cannot be avoided or to ensure information security of computer systems.
Section 2 Composition of the electronic computer room
Article 2.2.1 The composition of the electronic computer room shall be determined according to the computer's operating characteristics and specific requirements, generally, it should be composed of the master room, basic work room, first-class auxiliary room, second-class auxiliary room, and third-class auxiliary room.
Article 2.2.2 the use area of the electronic computer room shall be determined according to the layout of the shape and size of the computer equipment. When the shape and size of computer equipment are not fully controlled, the use area of the computer room shall comply with the following requirements:
1. The area of the master data center can be determined by the following methods:
1. When the computer system device has been selected, you can calculate it as follows:
A = K Σ S (2.2.2-1)
Formula A: area used by the computer master data center (m2 );
K -- coefficient, value range: 5 ~ 7;
S: The projected area (m2) of computer systems and auxiliary devices ).
2. When the device of the computer system has not been selected, you can calculate it as follows:
A = KN (2.2.2-1)
Type K-the area occupied by a single device. The value ranges from 4.5 ~ 5.5 (m2v/Unit );
N -- total number of devices in the host room.
2. The total area of the basic work room and the first auxiliary room should be equal to or greater than 1.5 times the area of the master room.
3. The machine preparation room, external user studio, hardware and software personnel office can be 5M2 ~ 4m2.
Section 3 device layout
Article 2.3.1 partition layout should be used for computer equipment. Generally, computer equipment can be divided into host area, storage area, data input area, data output area, communication area, and monitoring scheduling area. The specific division can be determined based on system configuration and management.
Article 2.3.2 equipment layout that requires frequent monitoring or operation shall be convenient for operation.
Article 2.3.3 dust and waste generation equipment shall be kept away from dust-sensitive equipment and shall be centrally arranged at the air outlets close to the equipment room.
Article 2.3.4 The distance between the channels and devices in the host room shall comply with the following requirements:
1. The distance between the two sides to the front of the cabinet should not be less than 1.5 m;
2. The Cabinet side (or no surface) should be less than 0.5 m away from the wall. When maintenance testing is required, the distance from the wall should not be less than 1.2 m;
3. The width of the aisle should not be less than 1.2 m.

Chapter 3 Environmental Conditions
Section 1 temperature, humidity and air dust concentration
Article 3.1.1 the temperature and humidity in the master and basic work rooms must meet the requirements of computer equipment.
Article 3.1.2 the internal temperature and humidity of the computer room shall meet the following requirements:
1. The temperature and humidity in the computer room at startup shall comply with Table 3.1.2-1.
Table 3.1.2-1 temperature and humidity of the computer room at startup
Level A Level B
Summer, winter, and all-year
Temperature 23 + 2 deg C 20 + 2 18-28 deg C ...... the remaining full text>
 
Network IDC Construction Scheme Design

The answer is based on the current situation.
1. Technical Options (what kind of LAN technology)
Star Gigabit Ethernet.
2. Network Design Planning
For the star structure, see the topology.
3. cable selection. Why.
Use unshielded cat6 twisted pair wires.
A. Due to space conditions, the device is located in the same network data center and the distance between devices is no more than 100 meters. The distance between devices cannot exceed the transmission distance limit of cat6 twisted pair wires.
B. The use of cat6 twisted pair enables Gigabit Ethernet to achieve a higher transmission speed.
C. Because the interference problem in the same network room is extremely small, unshielded cables save costs and fully meet actual needs.
4. device Selection: What kind of device and the number of devices are used.
A total of 31 ports need to be exchanged between the server and the client, and two switch cascade ports need to be occupied. If two switches are used, a total of 33 ports will be occupied.
Solution a: Based on the above selection and cost considerations, you can select 16 non-Network-managed full Gigabit Switches and 16 non-Network-managed full gigabit switches; or a 48-port full-gigabit instance (in fact, the 48-Port product is relatively small, there will be fewer models available on the market, and the 48-port switch product is more expensive ).
Solution B: although it only needs to be considered based on future scalability, manageability, and future savings on repeated investment in network devices. You can select 24 ports to manage two full-gigabit switches, or 48 ports to manage one full-gigabit switch.
For questions 5, 6, and 7, see the attached figure.