Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
The hashed password data type depends upon which hashing algorithm we are using. The hashing algorithm does not depends upon the input size because it produces a result of the same length. It gives the result in a series of hexadecimal digits, and we can reduce the hexadecimal digits by half with the help of UNHEX() function. There are various algorithms and data types to store values. MD5 − It can use char(32) or BINARY(16). SHA-1 − It can use data type char(40) or BINARY(20). Example of MD5 The following is an example − mysql> select MD5('This ... Read More
To install python MySQLdb module, we need to install Python current version i.e. 3.7 We need to find the location of Python Scripts where pip command is located. First, open the cmd and reach the location of Python Scripts. To open cmd, press “Windows+R” and type cmd. Here is the snapshot − Now reach where scripts are located. We will now install “MySQLdb” module. The steps are displayed in the following screenshot.
We can use a conditional clause called the WHERE Clause to filter out the results. Using this WHERE clause, we can specify a selection criteria to select the required records from a table. The HAVING clause specify filter conditions for a group of rows or aggregates WHERE clause cannot be used with aggregate function while HAVING can be used with aggregate function. The following is an example − Let us now create a table. mysql> create table WhereDemo -> ( -> Price int -> ); Query OK, 0 rows affected (0.64 sec) Inserting records into table. ... Read More
As the name “SHA256” suggest, it is 256 bits long. If we are using hexadecimal notation then digit codes represent 4 bits. In order to represent 256, we need 256/4 = 64 bits. We need a data type varchar(64) or char(64). Creating a table for our example. mysql> create table SHA256Demo -> ( -> Password varchar(64) -> ); Query OK, 0 rows affected (0.54 sec) Inserting records into table. mysql> insert into SHA256Demo values(' 4e2e1a39dba84a0b5a91043bb0e4dbef23970837'); Query OK, 1 row affected (0.18 sec) Displaying all records. mysql> select *From SHA256Demo; The following ... Read More
To check what character set a MySQL database/ table/ column is, let us see an example: A database which has the name ‘business’ and table name is ‘student’ which is already present in the database is used. Syntax in order to check the table character set. SELECT CCSA.character_set_name FROM information_schema.`TABLES` T, information_schema.`COLLATION_CHARACTER_SET_APPLICABILITY` CCSA WHERE CCSA.collation_name = T.table_collation AND T.table_schema = "yourDatabaseName" AND T.table_name = "yourTableName"; Applying the above syntax to display character set for table student. mysql> SELECT CCSA.character_set_name FROM information_schema.`TABLES` T, -> information_schema.`COLLATION_CHARACTER_SET_APPLICABILITY` CCSA -> WHERE CCSA.collation_name = T.table_collation -> ... Read More
In Python there is one container called the Dictionary. In the dictionaries, we can map keys to its value. Using dictionary the values can be accessed in constant time. But when the given keys are not present, it may occur some errors. In this section we will see how to handle these kind of errors. If we are trying to access missing keys, it may return errors like this. Example code Live Demo country_dict = {'India' : 'IN', 'Australia' : 'AU', 'Brazil' : 'BR'} print(country_dict['Australia']) print(country_dict['Canada']) # This will return error Output AU --------------------------------------------------------------------------- KeyErrorTraceback (most ... Read More
The ibdata1 file cannot shrink, it is a particularly troublesome feature of MySQL. The ibdata1 file can be shrinked if you delete all databases, remove the files and reload the mysqldump. We can configure MySQL so that each table, including its indexes, is stored as a separate file. It is enabled by default as of version 5.6.6 of MySQL. To setup our server to use separate files for each table, we need to change my.cnf in order to enable it. If your MySQL version is below 5.6.6, then you need to add it in my.cnf file. [mysqld] ... Read More
It lets you modify the compiler's line number and (optionally) the file name output for errors and warnings. Let us see some examples. #line 100 "demo" int a; // CS0168 on line 100 int b; // CS0168 on line 101 int c; // CS0168 on line 102 As shown above the example reports three warnings associated with line numbers. The #line 100 directive forces the line number to be 100 and until the next #line directive, the filename will be reported as "demo”. Let’s see ... Read More
To create a temporary table in a SELECT statement we use TEMPORARY keyword. This temporary table will be visible for the current session and whenever a session is closed, it is automatically destroyed. Two sessions can use the same temporary table. Creating a table. mysql> create table MyTableDemo -> ( -> id int, -> Name varchar(100) -> ); Query OK, 0 rows affected (0.69 sec) Inserting some records. mysql> insert into MyTableDemo values(1, 'John'); Query OK, 1 row affected (0.18 sec) mysql> insert into MyTableDemo values(2, 'Carol'); Query OK, 1 row affected (0.13 ... Read More
We can get the current time with the help of now() and adding 2 hours is done by giving the interval as 2. Firstly, collect information of the current time in the system with the help of now(). The current time is . The following is the query to get the current date and time. mysql> select now(); Here is the output. +---------------------+ | now() | +---------------------+ | 2018-11-01 12:58:40 | +---------------------+ 1 row in set (0.00 sec) To add 2 hours in the current time, we will use the DATE_ADD() function. mysql> select ... Read More