sqlite

Khóa học miễn phí SQLite – PHP nhận dự án làm có lương

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SQLite – PHP

In this chapter, you will learn how to use SQLite in PHP programs.

Installation

SQLite3 extension is enabled by default as of PHP 5.3.0. It”s possible to disable it by using –without-sqlite3 at compile time.

Windows users must enable php_sqlite3.dll in order to use this extension. This DLL is included with Windows distributions of PHP as of PHP 5.3.0.

For detailed installation instructions, kindly check our PHP tutorial and its official website.

PHP Interface APIs

Following are important PHP routines which can suffice your requirement to work with SQLite database from your PHP program. If you are looking for a more sophisticated application, then you can look into PHP official documentation.

Sr.No. API & Description
1

public void SQLite3::open ( filename, flags, encryption_key )

Opens SQLite 3 Database. If the build includes encryption, then it will attempt to use the key.

If the filename is given as ”:memory:”, SQLite3::open() will create an in-memory database in RAM that lasts only for the duration of the session.

If the filename is actual device file name, SQLite3::open() attempts to open the database file by using its value. If no file by that name exists, then a new database file by that name gets created.

Optional flags used to determine how to open the SQLite database. By default, open uses SQLITE3_OPEN_READWRITE | SQLITE3_OPEN_CREATE.
2

public bool SQLite3::exec ( string $query )

This routine provides a quick, easy way to execute SQL commands provided by sql argument, which can consist of more than one SQL command. This routine is used to execute a result-less query against a given database.
3

public SQLite3Result SQLite3::query ( string $query )

This routine executes an SQL query, returning an SQLite3Result object if the query returns results.
4

public int SQLite3::lastErrorCode ( void )

This routine returns the numeric result code of the most recent failed SQLite request.
5

public string SQLite3::lastErrorMsg ( void )

This routine returns English text describing the most recent failed SQLite request.
6

public int SQLite3::changes ( void )

This routine returns the number of database rows that were updated, inserted, or deleted by the most recent SQL statement.
7

public bool SQLite3::close ( void )

This routine closes a database connection previously opened by a call to SQLite3::open().
8

public string SQLite3::escapeString ( string $value )

This routine returns a string that has been properly escaped for safe inclusion in an SQL statement.

Connect to Database

Following PHP code shows how to connect to an existing database. If database does not exist, then it will be created and finally a database object will be returned.

<?php
   class MyDB extends SQLite3 {
      function __construct() {
         $this->open(''test.db'');
      }
   }
   $db = new MyDB();
   if(!$db) {
      echo $db->lastErrorMsg();
   } else {
      echo "Opened database successfullyn";
   }
?>

Now, let”s run the above program to create our database test.db in the current directory. You can change your path as per your requirement. If the database is successfully created, then it will display the following message −

Open database successfully

Create a Table

Following PHP program will be used to create a table in the previously created database.

<?php
   class MyDB extends SQLite3 {
      function __construct() {
         $this->open(''test.db'');
      }
   }
   $db = new MyDB();
   if(!$db) {
      echo $db->lastErrorMsg();
   } else {
      echo "Opened database successfullyn";
   }

   $sql =<<<EOF
      CREATE TABLE COMPANY
      (ID INT PRIMARY KEY     NOT NULL,
      NAME           TEXT    NOT NULL,
      AGE            INT     NOT NULL,
      ADDRESS        CHAR(50),
      SALARY         REAL);
EOF;

   $ret = $db->exec($sql);
   if(!$ret){
      echo $db->lastErrorMsg();
   } else {
      echo "Table created successfullyn";
   }
   $db->close();
?>

When the above program is executed, it will create the COMPANY table in your test.db and it will display the following messages −

Opened database successfully
Table created successfully

INSERT Operation

Following PHP program shows how to create records in the COMPANY table created in the above example.

<?php
   class MyDB extends SQLite3 {
      function __construct() {
         $this->open(''test.db'');
      }
   }
   
   $db = new MyDB();
   if(!$db){
      echo $db->lastErrorMsg();
   } else {
      echo "Opened database successfullyn";
   }

   $sql =<<<EOF
      INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY)
      VALUES (1, ''Paul'', 32, ''California'', 20000.00 );

      INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY)
      VALUES (2, ''Allen'', 25, ''Texas'', 15000.00 );

      INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY)
      VALUES (3, ''Teddy'', 23, ''Norway'', 20000.00 );

      INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY)
      VALUES (4, ''Mark'', 25, ''Rich-Mond '', 65000.00 );
EOF;

   $ret = $db->exec($sql);
   if(!$ret) {
      echo $db->lastErrorMsg();
   } else {
      echo "Records created successfullyn";
   }
   $db->close();
?>

When the above program is executed, it will create the given records in the COMPANY table and will display the following two lines.

Opened database successfully
Records created successfully

SELECT Operation

Following PHP program shows how to fetch and display records from the COMPANY table created in the above example −

<?php
   class MyDB extends SQLite3 {
      function __construct() {
         $this->open(''test.db'');
      }
   }
   
   $db = new MyDB();
   if(!$db) {
      echo $db->lastErrorMsg();
   } else {
      echo "Opened database successfullyn";
   }

   $sql =<<<EOF
      SELECT * from COMPANY;
EOF;

   $ret = $db->query($sql);
   while($row = $ret->fetchArray(SQLITE3_ASSOC) ) {
      echo "ID = ". $row[''ID''] . "n";
      echo "NAME = ". $row[''NAME''] ."n";
      echo "ADDRESS = ". $row[''ADDRESS''] ."n";
      echo "SALARY = ".$row[''SALARY''] ."nn";
   }
   echo "Operation done successfullyn";
   $db->close();
?>

When the above program is executed, it will produce the following result.

Opened database successfully
ID = 1
NAME = Paul
ADDRESS = California
SALARY = 20000

ID = 2
NAME = Allen
ADDRESS = Texas
SALARY = 15000

ID = 3
NAME = Teddy
ADDRESS = Norway
SALARY = 20000

ID = 4
NAME = Mark
ADDRESS = Rich-Mond
SALARY = 65000

Operation done successfully

UPDATE Operation

Following PHP code shows how to use UPDATE statement to update any record and then fetch and display the updated records from the COMPANY table.

<?php
   class MyDB extends SQLite3 {
      function __construct() {
         $this->open(''test.db'');
      }
   }
   
   $db = new MyDB();
   if(!$db) {
      echo $db->lastErrorMsg();
   } else {
      echo "Opened database successfullyn";
   }
   $sql =<<<EOF
      UPDATE COMPANY set SALARY = 25000.00 where ID=1;
EOF;
   $ret = $db->exec($sql);
   if(!$ret) {
      echo $db->lastErrorMsg();
   } else {
      echo $db->changes(), " Record updated successfullyn";
   }

   $sql =<<<EOF
      SELECT * from COMPANY;
EOF;
   
   $ret = $db->query($sql);
   while($row = $ret->fetchArray(SQLITE3_ASSOC) ) {
      echo "ID = ". $row[''ID''] . "n";
      echo "NAME = ". $row[''NAME''] ."n";
      echo "ADDRESS = ". $row[''ADDRESS''] ."n";
      echo "SALARY = ".$row[''SALARY''] ."nn";
   }
   echo "Operation done successfullyn";
   $db->close();
?>

When the above program is executed, it will produce the following result.

Opened database successfully
1 Record updated successfully
ID = 1
NAME = Paul
ADDRESS = California
SALARY = 25000

ID = 2
NAME = Allen
ADDRESS = Texas
SALARY = 15000

ID = 3
NAME = Teddy
ADDRESS = Norway
SALARY = 20000

ID = 4
NAME = Mark
ADDRESS = Rich-Mond
SALARY = 65000

Operation done successfully

DELETE Operation

Following PHP code shows how to use DELETE statement to delete any record and then fetch and display the remaining records from the COMPANY table.

<?php
   class MyDB extends SQLite3 {
      function __construct() {
         $this->open(''test.db'');
      }
   }
   
   $db = new MyDB();
   if(!$db) {
      echo $db->lastErrorMsg();
   } else {
      echo "Opened database successfullyn";
   }
   $sql =<<<EOF
      DELETE from COMPANY where ID = 2;
EOF;
   
   $ret = $db->exec($sql);
   if(!$ret){
     echo $db->lastErrorMsg();
   } else {
      echo $db->changes(), " Record deleted successfullyn";
   }

   $sql =<<<EOF
      SELECT * from COMPANY;
EOF;
   $ret = $db->query($sql);
   while($row = $ret->fetchArray(SQLITE3_ASSOC) ) {
      echo "ID = ". $row[''ID''] . "n";
      echo "NAME = ". $row[''NAME''] ."n";
      echo "ADDRESS = ". $row[''ADDRESS''] ."n";
      echo "SALARY = ".$row[''SALARY''] ."nn";
   }
   echo "Operation done successfullyn";
   $db->close();
?>

When the above program is executed, it will produce the following result.

Opened database successfully
1 Record deleted successfully
ID = 1
NAME = Paul
ADDRESS = California
SALARY = 25000

ID = 3
NAME = Teddy
ADDRESS = Norway
SALARY = 20000

ID = 4
NAME = Mark
ADDRESS = Rich-Mond
SALARY = 65000

Operation done successfully

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