面试题与答案

SQLite is a relational database management system which is self-contained, server-less and need zero configuration.

SQLite is a freely available open source database provided in Android. SQLite is a lightweight and compact database that does not require any kind of server to run. It is easily integrated into any kind of mobile.

SQLite was designed by D. Richard Hipp for the purpose of no administration required for operating a program.

There are lots of features which make SQLite very popular:

• SQlite is free of cost.
• SQLite is server-less.
• SQLite is flexible.
• SQLite doesn't need configuration.
• SQLite is cross-platform.
• SQlite is lightweight.

SQlite has the following main advantages:

• SQLite is very light weight database.
• Data storing is very easy and efficient.
• SQlite is very easy to learn and use.

In SQLite, sqlite3 command is used to create database.

Syntax:

sqlite3 my_database_name.db

CREATE TABLE statement is used to create a table in SQLite database. You have to define the columns and data types of each column while creating the table.

CREATE TABLE my_database_name.table_name(    

column1 datatype  PRIMARY KEY(one or more columns),    

column2 datatype,    

column3 datatype,    

columnN datatype,    

);    

DROP TABLE command is used to delete or permanently drop a table from SQLite database.

DROP TABLE my_table_name;

SQLite uses dynamic typing. Content can be stored as INTEGER, REAL, TEXT, BLOB, or as NULL.

INSERT INTO statement is used to insert data in a table in SQLite database. There are two ways to insert data in table:

Syntax A:

INSERT INTO TABLE_NAME [(column1, column2, column3,...columnN)]      

VALUES (value1, value2, value3,...valueN);   

Syntax B:

INSERT INTO TABLE_NAME VALUES (value1,value2,value3,...valueN);      

For autoincrement, you have to declare a column of the table to be INTEGER PRIMARY KEY, then whenever you insert a NULL into that column of the table, the NULL is automatically converted into an integer which is one greater than the largest value of that column over all other rows in the table, or 1 if the table is empty.