SQLite - SPLessons

SQLite Commands

Chapter 4

SPLessons 5 Steps, 3 Clicks
5 Steps - 3 Clicks

SQLite Commands

SQLite Commands

shape Description

The SQLite Commands are extremely basic and effectively comprehends for all the SQLite programmers. SQLite Commands are also called as SQLite Dot Commands. The special case with these speck orders is that it does not end using semi colon ;.

Each and every function in SQLite will be described in the operations given below, such as typing .help in SQLite Commands gives the entire details.

sqlite> .help
.auth ON|OFF           Show authorizer callbacks
.backup ?DB? FILE      Backup DB (default "main") to FILE
.bail on|off           Stop after hitting an error.  Default OFF
.binary on|off         Turn binary output on or off.  Default OFF
.changes on|off        Show number of rows changed by SQL
.clone NEWDB           Clone data into NEWDB from the existing database
.databases             List names and files of attached databases
.dbinfo ?DB?           Show status information about the database
.dump ?TABLE? ...      Dump the database in an SQL text format
                         If TABLE specified, only dump tables matching
                         LIKE pattern TABLE.
.echo on|off           Turn command echo on or off
.eqp on|off|full       Enable or disable automatic EXPLAIN QUERY PLAN
.exit                  Exit this program
.explain ?on|off|auto? Turn EXPLAIN output mode on or off or to automatic
.fullschema ?--indent? Show schema and the content of sqlite_stat tables
.headers on|off        Turn display of headers on or off
.help                  Show this message
.import FILE TABLE     Import data from FILE into TABLE
.indexes ?TABLE?       Show names of all indexes
                         If TABLE specified, only show indexes for tables
                         matching LIKE pattern TABLE.
.limit ?LIMIT? ?VAL?   Display or change the value of an SQLITE_LIMIT
.load FILE ?ENTRY?     Load an extension library
.log FILE|off          Turn logging on or off.  FILE can be stderr/stdout
.mode MODE ?TABLE?     Set output mode where MODE is one of:
                         ascii    Columns/rows delimited by 0x1F and 0x1E
                         csv      Comma-separated values
                         column   Left-aligned columns.  (See .width)
                         html     HTML

<table> code
                         insert   SQL insert statements for TABLE
                         line     One value per line
                         list     Values delimited by .separator strings
                         tabs     Tab-separated values
                         tcl      TCL list elements
.nullvalue STRING      Use STRING in place of NULL values
.once FILENAME         Output for the next SQL command only to FILENAME
.open ?FILENAME?       Close existing database and reopen FILENAME
.output ?FILENAME?     Send output to FILENAME or stdout
.print STRING...       Print literal STRING
.prompt MAIN CONTINUE  Replace the standard prompts
.quit                  Exit this program
.read FILENAME         Execute SQL in FILENAME
.restore ?DB? FILE     Restore content of DB (default "main") from FILE
.save FILE             Write in-memory database into FILE
.scanstats on|off      Turn sqlite3_stmt_scanstatus() metrics on or off
.schema ?PATTERN?      Show the CREATE statements matching PATTERN
                          Add --indent for pretty-printing
.separator COL ?ROW?   Change the column separator and optionally the row
                         separator for both the output mode and .import
.shell CMD ARGS...     Run CMD ARGS... in a system shell
.show                  Show the current values for various settings
.stats ?on|off?        Show stats or turn stats on or off
.system CMD ARGS...    Run CMD ARGS... in a system shell
.tables ?TABLE?        List names of tables
                         If TABLE specified, only list tables matching
                         LIKE pattern TABLE.
.timeout MS            Try opening locked tables for MS milliseconds
.timer on|off          Turn SQL timer on or off
.trace FILE|off        Output each SQL statement as it is run
.vfsinfo ?AUX?         Information about the top-level VFS
.vfslist               List all available VFSes
.vfsname ?AUX?         Print the name of the VFS stack
.width NUM1 NUM2 ...   Set column widths for "column" mode
                         Negative values right-justify

 

SQLite has standard definition languages and can be classified into 3 types such as :

Data Defination Language

shape Description

Data Definition Language(DDL) is used to define data in Database Server. DDL statements explains, how the pattern of data should be there in the database schema table.

DDL statements are classified into the following types:

Data manipulation Language

shape Description

Data manipulation language is utilized to manage data within the table. i.e. DML statements are used to manage data inside the schema objects, and includes most common standard query language statements such as select command and insert command. DML allows to add and modify the database table.

Following are the DML statements

Data Query Language

shape Description

DQL empowers the user to retrieve the required data from the database. Following are the DQL statements :

Create

shape Description

By using Create command in SQLite Commands, new table can be defined in the Database Server and the table name can be any character followed by size. This command will access the create privilege for the database and the table name should be unique in the database.

shape Syntax

Create table <table_name>(Post_id INTEGER NOT NULL PRIMARY KEY AUTO INCREMENT,name TEXT NOT NULL,email TEXT NOT NULL);

table_name => Any accurate table.

column_name => The operation that can be performed on a column in the table.

shape Examples

By using the below example, new table can be created by using create command.

sqlite> Create table comment(post_id INTEGER NOT NULL PRIMARY KEY AUTO INCREMENT,
name TEXT NOT NULL,email TEXT NOT NULL);
sqlite> .tables
comment

In the above example, a table comment is defined with column names post_id, name, and email.

Insert

shape Description

By using insert command new record can be inserted in the existing database table. i.e, inserting field value like name, email id and salary can be inserted.

shape Syntax

Insert into <table_name> values(<value1>,<value2>,<value3>…….);

table name => Accurate table.

values => values are the column values.

shape Examples

By using the below example, the concept of insert command can be understood easily.

sqlite> Create table comment(post_id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
name TEXT NOT NULL,email TEXT NOT NULL);
sqlite> .tables
comment
sqlite> Insert into comment(name,email)values('John','shah@gmail.com');
sqlite> Insert into comment(name,email)values('Mike','chah@gmail.com');
sqlite> select * from comment;
1|John|shah@gmail.com
2|Mike|chah@gmail.com

The above example tells that, when insert command is performed on the table comment then the table will accept the values and stores in the table database.

select

shape Description

Select statement of SQLite Commands will display all the details in the entire table that the user has entered.Select post_id, name, email id from comment;

shape Syntax

Select <value1>,<value2>,<valuen>from <table_name>;

table name => The accurate table.

values => values are the column values.

shape Examples

By viewing the below example, the concept of select command can be understood easily.

Select * from comment;

The above example tells that, when select command is performed on the table comment then it will accept the values and stores in the table database.

Summary

shape Key Points

  • SQLite Commands – Basic and effectively comprehend for all the SQLite programmers.
  • Data Definition Language – Used to define data in database server.
  • Data Manipulation Language – Used to manage data in database server.
  • Data Query Language – Retrieves data from the database server.