Mysql quick guide

Quick Reference Guide
S.Puvikanth, Temp. Demonstrator – CS,
Dept. of Mathematics, EUSL.
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GETTING START WITH MYSQL
1. Install WAMP or XAMPP or MYSQL SERVER on your computer
2. Starts the server and set the Mysql bin path on Command Prompt
XAMPP
[Eg.: cusermaths> cd c:xamppmysqlbin]
WAMP
[Eg.: cusermaths> cd c:wampbinmysqlmysql5.2.3bin]
Mysql Server
[Eg.: cusermaths> cd "c:program files(x86)mysqlmysql
server5.6bin"]
(Otherwise find the bin path)
3. Login into Mysql
If password is set
c:xamppmysqlbin> mysql -u root -p[password without space]
or
c:xamppmysqlbin> mysql -u root –p
Enter password:***** <<Type your password here, Press enter key>>
If password is not set
c:xamppmysqlbin> mysql -u root -p
Enter password: <<No need to type any letters, Press enter key>>

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[Here -u indicates user, -p indicates password and root is the admin user.]
4. If you want to save all your commands, log a file to save
mysql> tee "absolute path"
or
mysql>T "absolute path"
[Eg.: mysql> tee "D:myfoldermywork.txt"]
5. Show existing databases
mysql> SHOW DATABASES;

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6. Create a new database
mysql> CREATE DATABASE [IF NOT EXISTS] your_database_name;
[Eg.: mysql> CREATE DATABASE student;]
If there any database with same name it will try to create database then display error message
or
[Eg.: mysql> CREATE DATABASE IF NOT EXISTS student;]
If any database exist with same name it doesn't try to create
7. Open a database to have access
mysql> USE your_database;
8. Show opened database
mysql> SELECT DATABASE();
9. Create tables
mysql> CREATE TABLE your_table_name(
-> column1_name datatype [NOT NULL][AUTO INCREMENT],
-> column2_name datatype [DEFAULT "value"],
-> .....,
-> [PRIMARY KEY (column_name [,column name,...])],
-> [INDEX any_index_name column_name],
-> [CONSTRAINT any_fk_name FOREIGN KEY (column_name)
REFERENCES parent_table(column_name)
ON UPDATE [CASCADE|SET NULL|NO ACTION] ON DELETE
[CASCADE|SET NULL|NO ACTION]]);

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[Eg.:
--Parent table --
mysql> CREATE TABLE student(
-> name VARCHAR(20) NOT NULL,
-> index_no VARCHAR(6),
-> reg_no VARCAHR(10) NOT NULL,
-> gender ENUM('Male','Female') NOT NULL,
-> addr VARCHAR(20),
-> dob DATE,
-> nic VARCHAR(10) NOT NULL,
-> pwd BLOB,
-> PRIMARY KEY(index_no),
-> INDEX idx_stu_reg (reg_no),
-> INDEX idx_stu_nic (nic));
-- Child table –
mysql> CREATE TABLE marks(
-> index_no VARCHAR(6) NOT NULL,
-> sub_code VARCHAR(5) NOT NULL,
-> sub_marks TINYINT UNSIGNED NOT NULL,
-> INDEX idx_marks_index (index_no),
-> CONSTRAINT fk_marks_stu_index FOREIGN KEY (index_no)
-> REFERENCES student(index_no) ON UPDATE CASCADE ON DELETE
CASCADE);
]
[Hint: AUTO_INCREMENT field must be set as primary key, FOREIGN KEY …REFERENCES table
field also be set as PRIMARY KEY or INDEX ]
10. Describing table contents
mysql> DESC your_table_name;
[Eg.: mysql> DESC student; ]

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11. Show create definition of table
mysql> SHOW CREATE TABLE your_table_name;
[Eg.: mysql> SHOW CREATE TABLE student; ]
12. Inserting data to the tables
* Insert single row all fields
mysql> INSERT INTO your_table VALUES
-> ('val1','val2',.....);
* Insert single row certain fields
mysql> INSERT INTO your_table (field1,field2,field3) VALUES
-> ('val1','val2','val3');
* Insert multiple row all fields
mysql> INSERT INTO your_table VALUES
-> ('val1','val2',.....),
-> ('val1','val2',.....),
-> ('val1','val2',.....);

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* Load from external file (ie, sampledata.txt)
mysql> LOAD DATA LOCAL INFILE 'file_pathsampledata.txt'
-> INTO TABLE your_table_name
-> [FIELDS TERMINATED BY 't'] //use field termination character
-> LINES TERMINATED BY 'rn'
-> [(column1,column2,.....)]; //if want to insert certain fields
13. Inserting encrypted data into table
* Data types need to hold : TEXT, BLOB, MEDIUMTEXT, MEDIUMBLOB,
LONGTEXT, LONGBLOB
* Methods to encrypt : PASSWORD, ENCODE, DES_ENCRYPT, SHA1, MD5
mysql> INSERT INTO student(pwd) VALUES (PASSWORD('string’));
or
mysql> INSERT INTO student(pwd) VALUES (ENCODE('string’,'flag'));
Sample Encrypted String

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or
mysql> INSERT INTO student(pwd)
-> VALUES (DES_ENCRYPT('string','flag'));
or
mysql> INSERT INTO student(pwd) VALUES (SHA1('string’));
or
mysql> INSERT INTO student(pwd) VALUES (MD5('string'));
*Methods to decrypt : DECODE for encoded text, DES_DECRYPT for des_encrypted text
mysql> SELECT DECODE(encrypted_column,'flag') FROM student;

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or
mysql> SELECT DES_DECRYPT(encrypted_column,'flag') FROM student;
14. Update the fields
-- update all the records --
mysql> UPDATE table_name SET field1='value1',field2='value2',....;
Before Updating Gender Field
After Updating Gender Field
[So, all records have been affected.]

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or
-- update perticular records --
mysql> UPDATE table_name SET field1='value1',field2='value2',....
-> WHERE field='value';
[Hint: Must be careful when update tables. Use WHERE clause unless updating all records.]
15. Delete records
-- Delete all the records --
mysql> DELETE FROM table_name;
or
-- Delete particular records --
mysql> DELETE FROM table_name
-> WHERE field='value';
After Updating Gender Field
[So, certain records only have been affected.]
[So, all records have been deleted.]

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[Hint: Must be careful when delete records. Use WHERE clause unless deleting all records.]
16. Alteration on tables
*Add additional column
mysql> ALTER TABLE table_name
-> ADD COLUMN new_column_name datatype [FIRST | AFTER column_name];
*Rename or change column
-> CHANGE COLUMN old_column_name new_column_name datatype;
[So, particular record only has been deleted.]

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*change data type or modify
-> MODIFY old_column_name new_datatype;
*delete a column
-> DROP COLUMN column_name;
*Add primary key
-> ADD PRIMARY KEY (column1_name,column2_name,....);

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*Delete primary key
-> DROP PRIMARY KEY;
*Add index
-> ADD INDEX index_name (column_name);
*Delete index
-> DROP INDEX index_name;
*Add foreign key
-> ADD CONSTRAINT foreignkey_name
FOREIGN KEY (column_name)
REFERENCES parent_table(column_name)
ON UPDATE [NO ACTION| CASCADE | SET NULL]
ON DELETE [NO ACTION| CASCADE | SET NULL];
*Delete foreign key
-> DROP FOREIGN KEY foreignkey_name;

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*Rename table
-> RENAME TO new_table_name;
15. Delete a table
mysql> DROP TABLE [IF EXISTS] table_name;
[Eg.: mysql> DROP TABLE student; ]
16. Delete a database
mysql> DROP DATABASE [IF EXISTS] db_name;
[Eg.: mysql> DROP DATABASE mytest; ]
Before drop tables
After dropped tables
Before drop databases
After dropped databases

Mysql quick guide

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