DATABASE RECITATION

• Data Definition Language (DDL)


  DDL Statements define, modify and destroy the structure of database objects such as tables, indexes and views as well as the database itself. The CREATE, ALTER, and DROP statements are included under this category.
• CREATE


  Used to create database or its objects
• DROP


  Used to delete/remove objects from a database
• ALTER


  Used to modifies the structure of a table
• Data Manipulation Language (DML)


  DML Statements are used to manipulate the contents of a database by allowing insertion, deletion, modification and retrieval of the contents of tables. Common DML statements are SELECT, INSERT, UPDATE, and DELETE.
• INSERT INTO


  Used to insert new data into a table
• SELECT


  Retrieves data from a table
• UPDATE


  Modifies data stored in tables
• DELETE


  Removes a row/records from a table
• Data Control Language (DCL)


  DCL Statements are used to control a database, including committing data and administering privileges by authorizing certain users to view, change, or delete database objects and/or data in it.
• GRANT


  Gives user's access privileges to database
• REVOKE


  Withdraw user's access privileges given by using the GRANT command
• Comment


  A word, clause or statement added by the programmer to remind him of what a particular part of code does. Comments are ignored by the compiler.
• Single line comment


  Two consecutive hyphens is used
• Multiple line comment


  Backslash asterisk is used. Anything inside the /* and */ is ignored by the compiler.
• Identifiers


  Names given to database objects such as tables, columns, views, databases and servers
• Keywords


  Words with special meanings in SQL therefore are considered reserved and cannot be used as identifiers
• SQL Statement


  A grammatically acceptable and valid combination of indivisible parts (keywords, identifiers, operators, punctuation marks, literals or constraints) of the SQL language
• Clause


  A fragment of an SQL statement that is usually introduced by a keyword. The order of the clauses in an SQL statement is very important to produce grammatically correct SQL statement. A clause may be required or optional.
• Expression


  Any legal combination of keywords and numeric symbols that evaluates to a single data value
• Functions


  Sections of code that take zero, one, or more input values, perform a specific assignment and return a scalar or tabular set of values
• Operators


  Signs or symbols that can perform an operation between operands or between two or more than two expressions
• Semicolon


  Used to end SQL statements. In some variants of SQL (such as in MS SQL) semicolon is optional.
• Data Type


  Defines what type of data can be contained by a column, and what kind of operation can be performed on the data or values stored. It is an attribute that specifies the type of data of any object.
• CHAR


  Holds a fixed length combination of letters, numbers and special characters. The size parameter specifies the column length in characters can be from 0 to 255.
• VARCHAR


  Holds VARIABLE length string (can contain letters, numbers, and special characters). The size parameter specifies the maximum column length in characters - can be from 0 to 65535.
• BLOB


  Binary Large Objects, it holds and stores large objects such as text documents, images or videos. Holds up to 65,535 bytes of data.
• TINYINT


  A very small integer. Signed range is from -128 to 127. Unsigned range is from 0 to 255.
• SMALLINT


  A small integer. Signed range is from -32768 to 32767. Unsigned range is from 0 to 65535.
• INT


  A medium integer. Signed range is from -2147483648 to 2147483647. Unsigned range is from 0 to 4294967295.
• BIGINT


  A large integer. Signed range is from -9223372036854775808 to 9223372036854775807. Unsigned range is from 0 to 18446744073709551615.
• FLOAT(size,d)


  A floating point number. The total number of digits is specified in size. The number of digits after the decimal point is specified in the d parameter.
• DOUBLE(size,d)


  A normal-size floating point number. The total number of digits is specified in size. The number of digits after the decimal point is specified in the d parameter.
• DECIMAL(size,d)


  An exact fixed-point number. The total number of digits is specified in size. The number of digits after the decimal point is specified in the d parameter. The maximum number for size is 65. The maximum number for d is 30. The default value for size is 10. The default value for d is 0.
• DATE


  Holds date value in the format: YYYY-MM-DD. The supported range is from '1000-01-01' to '9999-12-31'
• DATETIME


  Holds a date and time combination in the format: YYYY-MM-DD hh:mm:ss. The supported range is from '1000-01-01 00:00:00' to '9999-12-31 23:59:59'
• CREATE DATABASE


  Used to create a new SQL database
• USE DATABASE


  Used to switch from the default database master to preferred database
• CREATE TABLE


  Used to create a new table in a database
• DROP TABLE


  Used to drop an existing table in a database