Monday, November 10, 2014

My First MySQL

He was the one who thaught me MySQL

http://www.newthinktank.com/2014/08/mysql-video-tutorial/

1. Login to MySQL 
 
  a. mysql5 -u mysqladmin -p
 
2. quit

 a. Quit MySQL
 
3. show databases;

 a. Display all databases
 
4. CREATE DATABASE test2;

 a. Create a database
 
5. USE test2;

 a. Make test2 the active database
 
6. SELECT DATABASE();

 a. Show the currently selected database
 
7. DROP DATABASE IF EXISTS test2;

 a. Delete the named database
 
 b. Slide about building tables (2)
 
8. CREATE TABLE student(
first_name VARCHAR(30) NOT NULL,
last_name VARCHAR(30) NOT NULL,
email VARCHAR(60) NULL,
street VARCHAR(50) NOT NULL,
city VARCHAR(40) NOT NULL,
state CHAR(2) NOT NULL DEFAULT "PA",
zip MEDIUMINT UNSIGNED NOT NULL,
phone VARCHAR(20) NOT NULL,
birth_date DATE NOT NULL,
sex ENUM('M', 'F') NOT NULL,
date_entered TIMESTAMP,
lunch_cost FLOAT NULL,
student_id INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY
);

a. VARCHAR(30) : Characters with an expected max length of 30

b. NOT NULL : Must contain a value

c. NULL : Doesn't require a value

d. CHAR(2) : Contains exactly 2 characters

e. DEFAULT "PA" : Receives a default value of PA

f. MEDIUMINT : Value no greater then 8,388,608

g. UNSIGNED : Can't contain a negative value

h. DATE : Stores a date in the format YYYY-MM-DD

i. ENUM('M', 'F') : Can contain either a M or F

j. TIMESTAMP : Stores date and time in this format YYYY-MM-DD-HH-MM-SS

k. FLOAT: A number with decimal spaces, with a value no bigger than 1.1E38 or smaller than -1.1E38

l. INT : Contains a number without decimals

m. AUTO_INCREMENT : Generates a number automatically that is one greater then the previous row

n. PRIMARY KEY (SLIDE): Unique ID that is assigned to this row of data

 I. Uniquely identifies a row or record 
 
 II. Each Primary Key must be unique to the row 
 
 III. Must be given a value when the row is created and that value can�t be NULL 
 
 IV. The original value can�t be changed It should be short 
 
 V. It�s probably best to auto increment the value of the key

o. Atomic Data & Table Templating

As your database increases in size, you are going to want everything to be organized, so that it can perform your queries quickly. If your tables are set up properly, your database will be able to crank through hundreds of thousands of bits of data in seconds.

How do you know how to best set up your tables though? Just follow some simple rules:

Every table should focus on describing just one thing. Ex. Customer Table would have name, age, location, contact information. It shouldn�t contain lists of anything such as interests, job history, past address, products purchased, etc.
After you decide what one thing your table will describe, then decide what things you need to describe that thing. Refer to the customer example given in the last step.

Write out all the ways to describe the thing and if any of those things requires multiple inputs, pull them out and create a new table for them. For example, a list of past employers.

Once your table values have been broken down, we refer to these values as being atomic. Be careful not to break them down to a point in which the data is harder to work with. It might make sense to create a different variable for the house number, street name, apartment number, etc.; but by doing so you may make your self more work? That decision is up to you?

p. Some additional rules to help you make your data atomic: Don�t have multiple columns with the same sort of information. Ex. If you wanted to include a employment history you should create job1, job2, job3 columns. Make a new table with that data instead. 

Don�t include multiple values in one cell. Ex. You shouldn�t create a cell named jobs and then give it the value: McDonalds, Radio Shack, Walmart,� Normalized Tables

q. What does normalized mean?

Normalized just means that the database is organized in a way that is considered standardized by professional SQL programmers. So if someone new needs to work with the tables they�ll be able to understand how to easily.

Another benefit to normalizing your tables is that your queries will run much quicker and the chance your database will be corrupted will go down. 

r. What are the rules for creating normalized tables:

The tables and variables defined in them must be atomic Each row must have a Primary Key defined. Like your social security number identifies you, the Primary Key will identify your row. 

You also want to eliminate using the same values repeatedly in your columns. Ex. You wouldn�t want a column named instructors, in which you hand typed in their names each time. You instead, should create an instructor table and link to it�s key. 

Every variable in a table should directly relate to the primary key. Ex. You should create tables for all of your customers potential states, cities and zip codes, instead of including them in the main customer table. Then you would link them using foreign keys. Note: Many people think this last rule is overkill and can be ignored! 

No two columns should have a relationship in which when one changes another must also change in the same table. This is called a Dependency. Note: This is another rule that is sometimes ignored.

------------ Numeric Types ------------

TINYINT: A number with a value no bigger than 127 or smaller than -128
SMALLINT: A number with a value no bigger than 32,768 or smaller than -32,767
MEDIUM INT: A number with a value no bigger than 8,388,608 or smaller than -8,388,608
INT: A number with a value no bigger than 2^31 or smaller than 2^31 � 1
BIGINT: A number with a value no bigger than 2^63 or smaller than 2^63 � 1
FLOAT: A number with decimal spaces, with a value no bigger than 1.1E38 or smaller than -1.1E38
DOUBLE: A number with decimal spaces, with a value no bigger than 1.7E308 or smaller than -1.7E308

------------ String Types ------------

CHAR: A character string with a fixed length
VARCHAR: A character string with a length that�s variable
BLOB: Can contain 2^16 bytes of data
ENUM: A character string that has a limited number of total values, which you must define.
SET: A list of legal possible character strings. Unlike ENUM, a SET can contain multiple values in comparison to the one legal value with ENUM.

------------ Date & Time Types ------------

DATE: A date value with the format of (YYYY-MM-DD)
TIME: A time value with the format of (HH:MM:SS)
DATETIME: A time value with the format of (YYYY-MM-DD HH:MM:SS)
TIMESTAMP: A time value with the format of (YYYYMMDDHHMMSS)
YEAR: A year value with the format of (YYYY)

9. DESCRIBE student;

 a. Show the table set up
 
10. INSERT INTO student VALUES('Dale', 'Cooper', 'dcooper@aol.com', 
 '123 Main St', 'Yakima', 'WA', 98901, '792-223-8901', "1959-2-22",
 'M', NOW(), 3.50, NULL);
 
 a. Inserting Data into a Table 
 
 b. INSERT INTO student VALUES('Harry', 'Truman', 'htruman@aol.com', 
 '202 South St', 'Vancouver', 'WA', 98660, '792-223-9810', "1946-1-24",
 'M', NOW(), 3.50, NULL);
 
 INSERT INTO student VALUES('Shelly', 'Johnson', 'sjohnson@aol.com', 
 '9 Pond Rd', 'Sparks', 'NV', 89431, '792-223-6734', "1970-12-12",
 'F', NOW(), 3.50, NULL);
 
 INSERT INTO student VALUES('Bobby', 'Briggs', 'bbriggs@aol.com', 
 '14 12th St', 'San Diego', 'CA', 92101, '792-223-6178', "1967-5-24",
 'M', NOW(), 3.50, NULL);
 
 INSERT INTO student VALUES('Donna', 'Hayward', 'dhayward@aol.com', 
 '120 16th St', 'Davenport', 'IA', 52801, '792-223-2001', "1970-3-24",
 'F', NOW(), 3.50, NULL);
 
 INSERT INTO student VALUES('Audrey', 'Horne', 'ahorne@aol.com', 
 '342 19th St', 'Detroit', 'MI', 48222, '792-223-2001', "1965-2-1",
 'F', NOW(), 3.50, NULL);
 
 INSERT INTO student VALUES('James', 'Hurley', 'jhurley@aol.com', 
 '2578 Cliff St', 'Queens', 'NY', 11427, '792-223-1890', "1967-1-2",
 'M', NOW(), 3.50, NULL);
 
 INSERT INTO student VALUES('Lucy', 'Moran', 'lmoran@aol.com', 
 '178 Dover St', 'Hollywood', 'CA', 90078, '792-223-9678', "1954-11-27",
 'F', NOW(), 3.50, NULL);
 
 INSERT INTO student VALUES('Tommy', 'Hill', 'thill@aol.com', 
 '672 High Plains', 'Tucson', 'AZ', 85701, '792-223-1115', "1951-12-21",
 'M', NOW(), 3.50, NULL);
 
 INSERT INTO student VALUES('Andy', 'Brennan', 'abrennan@aol.com', 
 '281 4th St', 'Jacksonville', 'NC', 28540, '792-223-8902', "1960-12-27",
 'M', NOW(), 3.50, NULL);

11. SELECT * FROM student;

 a. Shows all the student data
 
12. CREATE TABLE class(
 name VARCHAR(30) NOT NULL,
 class_id INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY);
 
 a. Create a separate table for all classes

13. show tables;

 a. Show all the tables

14. INSERT INTO class VALUES
('English', NULL), ('Speech', NULL), ('Literature', NULL),
('Algebra', NULL), ('Geometry', NULL), ('Trigonometry', NULL),
('Calculus', NULL), ('Earth Science', NULL), ('Biology', NULL),
('Chemistry', NULL), ('Physics', NULL), ('History', NULL),
('Art', NULL), ('Gym', NULL);

 a. Insert all possible classes
 
 b. select * from class; 
 
15. CREATE TABLE test(
 date DATE NOT NULL,
 type ENUM('T', 'Q') NOT NULL,
 class_id INT UNSIGNED NOT NULL,
 test_id INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY);
 
 a. class_id is a foreign key
 
 I. Used to make references to the Primary Key of another table 
 
 II. Example: If we have a customer and city table. If the city table had a column which listed the unique primary key of all the customers, that Primary Key listing in the city table would be considered a Foreign Key. 
 
 III. The Foreign Key can have a different name from the Primary Key name. 
 
 IV. The value of a Foreign Key can have the value of NULL. 
 
 V. A Foreign Key doesn�t have to be unique

16. CREATE TABLE score(
 student_id INT UNSIGNED NOT NULL,
 event_id INT UNSIGNED NOT NULL,
 score INT NOT NULL,
 PRIMARY KEY(event_id, student_id));
 
 a. We combined the event and student id to make sure we don't have 
 duplicate scores and it makes it easier to change scores
 
 b. Since neither the event or the student ids are unique on their 
 own we are able to make them unique by combining them
 
17. CREATE TABLE absence(
 student_id INT UNSIGNED NOT NULL,
 date DATE NOT NULL,
 PRIMARY KEY(student_id, date));
 
 a. Again we combine 2 items that aren't unique to generate a 
 unique key
 
18. Add a max score column to test

 a. ALTER TABLE test ADD maxscore INT NOT NULL AFTER type; 
 
 b. DESCRIBE test;

19. Insert Tests

 a. INSERT INTO test VALUES
 ('2014-8-25', 'Q', 15, 1, NULL),
 ('2014-8-27', 'Q', 15, 1, NULL),
 ('2014-8-29', 'T', 30, 1, NULL),
 ('2014-8-29', 'T', 30, 2, NULL),
 ('2014-8-27', 'Q', 15, 4, NULL),
 ('2014-8-29', 'T', 30, 4, NULL);
 
 b. select * FROM test;
 
20. ALTER TABLE score CHANGE event_id test_id 
 INT UNSIGNED NOT NULL;
 
 a. Change the name of event_id in score to test_id
 
 b. DESCRIBE score;


21. Enter student scores

 a. INSERT INTO score VALUES
 (1, 1, 15),
 (1, 2, 14),
 (1, 3, 28),
 (1, 4, 29),
 (1, 5, 15),
 (1, 6, 27),
 (2, 1, 15),
 (2, 2, 14),
 (2, 3, 26),
 (2, 4, 28),
 (2, 5, 14),
 (2, 6, 26),
 (3, 1, 14),
 (3, 2, 14),
 (3, 3, 26),
 (3, 4, 26),
 (3, 5, 13),
 (3, 6, 26),
 (4, 1, 15),
 (4, 2, 14),
 (4, 3, 27),
 (4, 4, 27),
 (4, 5, 15),
 (4, 6, 27),
 (5, 1, 14),
 (5, 2, 13),
 (5, 3, 26),
 (5, 4, 27),
 (5, 5, 13),
 (5, 6, 27),
 (6, 1, 13),
 (6, 2, 13),
 # Missed this day (6, 3, 24),
 (6, 4, 26),
 (6, 5, 13),
 (6, 6, 26),
 (7, 1, 13),
 (7, 2, 13),
 (7, 3, 25),
 (7, 4, 27),
 (7, 5, 13),
 # Missed this day (7, 6, 27),
 (8, 1, 14),
 # Missed this day (8, 2, 13),
 (8, 3, 26),
 (8, 4, 23),
 (8, 5, 12),
 (8, 6, 24),
 (9, 1, 15),
 (9, 2, 13),
 (9, 3, 28),
 (9, 4, 27),
 (9, 5, 14),
 (9, 6, 27),
 (10, 1, 15),
 (10, 2, 13),
 (10, 3, 26),
 (10, 4, 27),
 (10, 5, 12),
 (10, 6, 22);
 
22. Fill in the absences

 a. INSERT INTO absence VALUES
 (6, '2014-08-29'),
 (7, '2014-08-29'),
 (8, '2014-08-27');
 
23. SELECT * FROM student;

 a. Shows everything in the student table
 
24. SELECT FIRST_NAME, last_name 
 FROM student;
 
 a. Show just selected data from the table (Not Case Sensitive)
 
25. RENAME TABLE 
 absence to absences,
 class to classes,
 score to scores,
 student to students,
 test to tests;
 
 a. Change all the table names SHOW TABLES;
 
26. SELECT first_name, last_name, state 
 FROM students
 WHERE state="WA";
 
 a. Show every student born in the state of Washington
 
27. SELECT first_name, last_name, birth_date
 FROM students
 WHERE YEAR(birth_date) >= 1965;
 
 a. You can compare values with =, >, <, >=, <=, !=
 
 b. To get the month, day or year of a date use MONTH(), DAY(), or YEAR()
 
27. SELECT first_name, last_name, birth_date
 FROM students
 WHERE MONTH(birth_date) = 2 OR state="CA";
 
 a. AND, && : Returns a true value if both conditions are true 

 b. OR, || : Returns a true value if either condition is true 

 c. NOT, ! : Returns a true value if the operand is false
 
28. SELECT last_name, state, birth_date
 FROM students
 WHERE DAY(birth_date) >= 12 && (state="CA" || state="NV");
 
 a. You can use compound logical operators
 
29. SELECT last_name
 FROM students
 WHERE last_name IS NULL;
 
 SELECT last_name
 FROM students
 WHERE last_name IS NOT NULL;
 
 a. If you want to check for NULL you must use IS NULL or IS NOT NULL
 
30. SELECT first_name, last_name
 FROM students
 ORDER BY last_name;
 
 a. ORDER BY allows you to order results. To change the order use
 ORDER BY col_name DESC;
 
31. SELECT first_name, last_name, state
 FROM students
 ORDER BY state DESC, last_name ASC;

 a. If you use 2 ORDER BYs it will order one and then the other
 
32. SELECT first_name, last_name
 FROM students
 LIMIT 5;
 
 a. Use LIMIT to limit the number of results
 
33. SELECT first_name, last_name
 FROM students
 LIMIT 5, 10;
 
 a. You can also get results 5 through 10
 
34. SELECT CONCAT(first_name, " ", last_name) AS 'Name',
 CONCAT(city, ", ", state) AS 'Hometown'
 FROM students;
 
 a. CONCAT is used to combine results
 
 b. AS provides for a way to define the column name
 
35. SELECT last_name, first_name
 FROM students
 WHERE first_name LIKE 'D%' OR last_name LIKE '%n';
 
 a. Matchs any first name that starts with a D, or ends with a n
 
 b. % matchs any sequence of characters
 
36. SELECT last_name, first_name
 FROM students
 WHERE first_name LIKE '___y';
 
 a. _ matchs any single character
 
37. SELECT DISTINCT state
 FROM students
 ORDER BY state;
 
 a. Returns the states from which students are born because DISTINCT
 eliminates duplicates in results
 
38. SELECT COUNT(DISTINCT state)
 FROM students;
 
 a. COUNT returns the number of matchs, so we can get the number
 of DISTINCT states from which students were born
 
39. SELECT COUNT(*)
 FROM students;
 
 SELECT COUNT(*)
 FROM students
 WHERE sex='M';
 
 a. COUNT returns the total number of records as well as the total
 number of boys
 
40. SELECT sex, COUNT(*)
 FROM students
 GROUP BY sex;
 
 a. GROUP BY defines how the results will be grouped
 
41. SELECT MONTH(birth_date) AS 'Month', COUNT(*)
 FROM students
 GROUP BY Month
 ORDER BY Month;
 
 a. We can get each month in which we have a birthday and the total
 number for each month
 
42. SELECT state, COUNT(state) AS 'Amount'
 FROM students
 GROUP BY state
 HAVING Amount > 1;
 
 a. HAVING allows you to narrow the results after the query is executed
 
43. SELECT
 test_id AS 'Test',
 MIN(score) AS min,
 MAX(score) AS max,
 MAX(score)-MIN(score) AS 'range',
 SUM(score) AS total,
 AVG(score) AS average
 FROM scores
 GROUP BY test_id;
 
 a. There are many math functions built into MySQL. Range had to be quoted because it is a reserved word.
 
 b. You can find all reserved words here http://dev.mysql.com/doc/mysqld-version-reference/en/mysqld-version-reference-reservedwords-5-5.html
 
44. The Built in Numeric Functions (SLIDE) 

ABS(x) : Absolute Number: Returns the absolute value of the variable x.

ACOS(x), ASIN(x), ATAN(x), ATAN2(x,y), COS(x), COT(x), SIN(x), TAN(x) :Trigonometric Functions : They are used to relate the angles of a triangle to the lengths of the sides of a triangle.

AVG(column_name) : Average of Column : Returns the average of all values in a column. SELECT AVG(column_name) FROM table_name;

CEILING(x) : Returns the smallest number not less than x.

COUNT(column_name) : Count : Returns the number of non null values in the column. SELECT COUNT(column_name) FROM table_name;

DEGREES(x) : Returns the value of x, converted from radians to degrees.

EXP(x) : Returns e^x

FLOOR(x) : Returns the largest number not grater than x

LOG(x) : Returns the natural logarithm of x

LOG10(x) : Returns the logarithm of x to the base 10

MAX(column_name) : Maximum Value : Returns the maximum value in the column. SELECT MAX(column_name) FROM table_name;

MIN(column_name) : Minimum : Returns the minimum value in the column. SELECT MIN(column_name) FROM table_name;

MOD(x, y) : Modulus : Returns the remainder of a division between x and y

PI() : Returns the value of PI

POWER(x, y) : Returns x ^ Y

RADIANS(x) : Returns the value of x, converted from degrees to radians

RAND() : Random Number : Returns a random number between the values of 0.0 and 1.0

ROUND(x, d) : Returns the value of x, rounded to d decimal places

SQRT(x) : Square Root : Returns the square root of x

STD(column_name) : Standard Deviation : Returns the Standard Deviation of values in the column. SELECT STD(column_name) FROM table_name;

SUM(column_name) : Summation : Returns the sum of values in the column. SELECT SUM(column_name) FROM table_name;

TRUNCATE(x) : Returns the value of x, truncated to d decimal places
 
45. SELECT * FROM absences; 

 DESCRIBE scores;
 
 SELECT student_id, test_id
 FROM scores
 WHERE student_id = 6;
 
 INSERT INTO scores VALUES
 (6, 3, 24);

 DELETE FROM absences 
 WHERE student_id = 6;
 
 a. Look up students that missed a test
 
 b. Look up the specific test missed by student 6
 
 c. Insert the make up test result
 
 d. Delete the record in absences
 
46. ALTER TABLE absences
 ADD COLUMN test_taken CHAR(1) NOT NULL DEFAULT 'F'
 AFTER student_id; 
 
 a. Use ALTER to add a column to a table. You can use AFTER
 or BEFORE to define the placement

47. ALTER TABLE absences
 MODIFY COLUMN test_taken ENUM('T','F') NOT NULL DEFAULT 'F';
 
 a. You can change the data type with ALTER and MODIFY COLUMN
 
48. ALTER TABLE absences
 DROP COLUMN test_taken;
 
 a. ALTER and DROP COLUMN can delete a column

49. ALTER TABLE absences
 CHANGE student_id student_id INT UNSIGNED NOT NULL;
 
 a. You can change the data type with ALTER and CHANGE
 
50. SELECT *
    FROM scores
    WHERE student_id = 4;

 UPDATE scores SET score=25 
 WHERE student_id=4 AND test_id=3;
 
 a. Use UPDATE to change a value in a row
 
51. SELECT first_name, last_name, birth_date
 FROM students
 WHERE birth_date 
 BETWEEN '1960-1-1' AND '1970-1-1';
 
 a. Use BETWEEN to find matches between a minimum and maximum
 
52. SELECT first_name, last_name
 FROM students
 WHERE first_name IN ('Bobby', 'Lucy', 'Andy');
 
 a. Use IN to narrow results based on a predefined list of options
 
53. SELECT student_id, date, score, maxscore
 FROM tests, scores
 WHERE date = '2014-08-25'
 AND tests.test_id = scores.test_id;
 
 a. To combine data from multiple tables you can perform a JOIN
 by matching up common data like we did here with the test ids
 
 b. You have to define the 2 tables to join after FROM
 
 c. You have to define the common data between the tables after WHERE
 
54. SELECT scores.student_id, tests.date, scores.score, tests.maxscore
 FROM tests, scores
 WHERE date = '2014-08-25'
 AND tests.test_id = scores.test_id;
 
 a. It is good to qualify the specific data needed by proceeding
 it with the tables name and a period
 
 b. The test_id that is in scores is an example of a foreign key, which 
 is a reference to a primary key in the tests table
 
55. SELECT CONCAT(students.first_name, " ", students.last_name) AS Name, 
 tests.date, scores.score, tests.maxscore
 FROM tests, scores, students
 WHERE date = '2014-08-25'
 AND tests.test_id = scores.test_id
 AND scores.student_id = students.student_id;
 
 a. You can JOIN more then 2 tables as long as you define the like 
 data between those tables
 
56. SELECT students.student_id, 
 CONCAT(students.first_name, " ", students.last_name) AS Name,
 COUNT(absences.date) AS Absences
 FROM students, absences
 WHERE students.student_id = absences.student_id
 GROUP BY students.student_id;
 
 a. If we wanted a list of the number of absences per student we
 have to group by student_id or we would get just one result
 
57. SELECT students.student_id, 
 CONCAT(students.first_name, " ", students.last_name) AS Name,
 COUNT(absences.date) AS Absences
 FROM students LEFT JOIN absences
 ON students.student_id = absences.student_id
 GROUP BY students.student_id;
 
 a. If we need to include all information from the table listed
 first "FROM students", even if it doesn't exist in the table on
 the right "LEFT JOIN absences", we can use a LEFT JOIN.
 
58. SELECT students.first_name, 
 students.last_name,
 scores.test_id,
 scores.score
 FROM students
 INNER JOIN scores
 ON students.student_id=scores.student_id
 WHERE scores.score <= 15
 ORDER BY scores.test_id;
 
 a. An INNER JOIN gets all rows of data from both tables if there
 is a match between columns in both tables
 
 b. Here I'm getting all the data for all quizzes and matching that 
 data up based on student ids
 
59. One-to-One Relationship (SLIDE)

 a. In this One-to-One relationship there can only be one social security number per person. Hence,  each social security number can be associated with one person. As well, one person in the other table only matches up with one social security number.

 b. One-to-One relationships can be identified also in that the foreign keys never duplicate across all rows.

 c. If you are confused by the One-to-One relationship it is understandable, because they are not often used. Most of the time if a value never repeats it should remain in the parent table being customer in this case. Just understand that in a One-to-One relationship, exactly one row in a parent table is related to exactly one row of a child table.

60. One-to-Many Relationship

 a. When we are talking about One-to-Many relationships think about the table diagram here. If you had a list of customers chances are some of them would live in the same state. Hence, in the state column in the parent table, it would be common to see a duplication of states. In this example, each customer can only live in one state so their would only be one id used for each customer.

 b. Just remember that, a One-to-Many relationship is one in which a record in the parent table can have many matching records in the child table, but a record in the child can only match one record in the parent. A customer can choose to live in any state, but they can only live in one at a time.

61. Many-to-Many Relationship

 a. Many people can own many different products. In this example, you can see an example of a Many-to-Many relationship. This is a sign of a non-normalized database, by the way. How could you ever access this information:

 b. If a customer buys more than one product, you will have multiple product id�s associated with each customer. As well, you would have multiple customer id�s associated with each product.


Just coppied from: newthinktank

Sunday, November 9, 2014

A simple PHP

This is the PHP program that I did successfully for the first time.

Some things I know About GIT

You know well that I can stick learning the same thing always so this time its GIT what ever I learn or do this GIT is common to all.

GIT is a version control system.
  • Version Control System is divided as 
    • Local Version Control
    • Centralized Version Control
    • Distributed Version Control
  • Files Transition between 3 states
    • Modified File
    • Staged File
    • Committed File
  • Command for initializing GIT: $ git init
  • To add all java files: $ git aad *.java
  • To add AndroidMAnifest files: $ git aad AndroidManifest.xml
  • To ignore common Files create a file named .gitignore 
    • and add the file types
    • common files can be found here https://github.com/github/gitignore
  • To commit: git commit -m 'initial project version'
  • To get the status : git status
  • To see the changes : git diff
  • To undo a commit : git commit --amend
  • To undo before commit: git reset HEAD filename.ext
INSTALLING GIT

1. Mac : http://sourceforge.net/projects/git-osx-installer/

2. Windows : http://msysgit.github.io/

3. Linux : apt-get install git-core OR yum install git-core

ABOUT GIT

1. Git is a version control tool that saves changes to groups of files so you can revert back if needed.

2. There are different types of version control tools

a. Local Version Control saves changes to files in a database

b. Centralized Version Control saves changes to a shared server

c. Distributed Version Control allows for easier sharing of files then LVC and also eliminates problems that could occur if access to the server is lost under a CVC system.

d. DVC clients have a complete backup of the files on their computer. If the server is lost the client just waits to regain contact and then uploads changes.

3. When you commit changes to files Git stores a reference of what the files look like at that moment. If a file isn't changed it isn't stored again.

4. Each client has a complete history of all changes stored locally. The client can also access all changes made to the files historically with a simple command. Also those files cannot be changed without Git knowing and changes are difficult to lose.

5. Files transition between 3 states with Git

a. Modified Files are files that have been recently changed

b. Staged Files have been marked to be saved

c. Committed Files are those that have been saved

6. Git saves all file changes to a directory as a compressed database. 

a. You modify files in Working Directory

b. You notify that want to save changes in your Staging Area

c. After you Commit the file changes are saved in the Git directory

USING GIT

1. git config --global user.name "Derek Banas" 

2. git config --global user.email derekbanas@verizon.net

3. git config --global core.editor "vim" # Set editor as vim

4. git config --global core.editor "edit -w" # Set editor as Text Wrangler Mac

5. git config --list # Show settings

6. git help OR git help [COMMAND] OR git help add

7. ---------------- Track a directory ----------------

a. Go to directory

b. ls -a shows all files

c. git init # Creates the .git directory

8. ---------------- Start tracking files ----------------

a. By type : git add *.java

b. By name : git add AndroidManifest.xml

9. ---------------- Ignore Files ----------------

a. Create a .gitignore file

b. https://github.com/github/gitignore

10. ---------------- git commit -m 'Initial project version' 

a. Commits the changes and sets an abbreviated commit message

11. ---------------- git status ----------------

a. Shows the state of your files meaning if they are tracked, have been modified and the branch your on.

12. ---------------- Stage A Modified File ----------------

a. Change the file and save

b. git diff # Shows what you changed, but haven't staged

c. git add AndroidManifest.xml # Stage file

d. git diff --cached # Shows what has been staged, but not committed 

13. ---------------- Commit The Changes ----------------

a. commit # Opens the editor we defined above or vi

b. In vi click [ESC] i to enter insert mode

c. Type a heading that briefly explains the changes in 50 characters or less

d. Describes the original problem that is being addressed

e. Describes the specific change being made

f. Describes the result of the change

g. Describes any future improvements

h. Post a closes bug notation Closes-Bug: #1291621

i. Hit [ESC] and type wq to save and exit

j. git commit -a -m 'Changed comment' # Skips staging and commit message

14. ---------------- Remove a File ----------------

a. rm DeleteMe.txt # If you remove a file it shows as "Changed but not updated"

b. git status # If you remove a file it shows as "Changed but not updated"

c. git rm DeleteMe.txt

d. git status # Shows that the file was deleted

e. If you have committed a file to be removed you must add the -f option

f. git rm --cached DeleteMe.txt # Keep file, but remove from staging area

g. git mv DeleteMe.txt Delete.txt # Renames a file

15. ---------------- Log Commit History  ----------------

a. git log # Shows all of the previous commit messages in reverse order

b. git log --pretty=oneline # Shows commits on one line

c. git log --pretty=format:"%h : %an : %ar : %s" 

I. %h - Abbreviated Hash  

II. %an - Authors Name

III. %ar - Date Changed

IV. %s - First Line of Comment

d. git log -p -2 # Shows the last 2 commit changes

e. git log --stat # Prints abbreviated stats

f. git log --since=1.weeks # Show only changes in the last week

g. git log --since="2014-04-12" # Show changes since this date

h. git log --author="Derek Banas" # Changes made by author

i. git log --before="2014-04-13" # Changes made before this date

16. ---------------- Undoing a Commit ----------------

a. git commit --amend # If you want to change your previous commit

b. Normally done if you forgot to stage a file, or to change the commit message

17. ---------------- Unstage a File ---------------- 

a. git reset HEAD AndroidManifest.xml

courtesy:http://www.newthinktank.com/2014/04/git-video-tutorial/

Friday, October 31, 2014