This tutorial shows you how to create a simple trigger in MySQL to audit the changes of a table. We will explain the syntax of the CREATE TRIGGER statement in detail. A while ago I did some research about MySQL audit functionality and logon a and logoff triggers. MySQL and MariaDB provide a logon trigger in the form of the init.
![]() My. SQL PHP tutorial - My. SQL programming with PHP. This is a PHP programming tutorial for the My. SQL database. It covers the. My. SQL programming with PHP. It uses the generic mysql module. The examples were created and tested on Ubuntu Linux. There is a similar. My. SQL C API tutorial. My. SQL Python tutorial. Mongo. DB PHP tutorial, and. Postgre. SQL PHP tutorial on Zet. Code. If you need to refresh your knowledge of the PHP language, there is a full. PHP tutorial on Zet. Code. About My. SQL database. My. SQL is a leading open source database management system. It is a multiuser. My. SQL is especially popular on the web. It is one of the parts of the very popular LAMP platform. Linux, Apache. My. SQL, and PHP. Currently My. SQL is owned by Oracle. My. SQL database is available. OS platforms. It runs on BSD Unix, Linux, Windows, or Mac OS. Wikipedia and You. Tube use My. SQL. These sites manage millions of queries. My. SQL comes in two versions: My. SQL server system and My. SQL. embedded system. Before we start. We need to install several packages to execute the examples in this tutorial. The php. 5- cli is the command line interpreter for the PHP5 programming language. All examples in this tutorial are created on the console. I have intentionally skipped. PHP and My. SQL. If you don't already have My. SQL installed, we must install it. This command installs the My. SQL server and various other packages. While installing the package, we are prompted to enter. My. SQL root account. Next, we are going to create a new database user and a new database. We use the mysql client. We check if the My. SQL server is running. If not, we need. to start the server. On Ubuntu Linux, this can be done. The above command is a common way to start My. SQL if we have. installed the My. SQL database from packages. The above command starts My. SQL server using the My. SQL server. startup script. The way how we start a My. SQL server might. It depends whether we have installed My. SQL. from sources or from packages and also on the Linux distro. For further information consult. My. SQL first steps. Linux distro information. Next, we are going to create a new database user and a new database. We use the mysql client. Enter password. Welcome to the My. SQL monitor. Commands end with ; or \g. Your My. SQL connection id is 3. Server version: 5. Ubuntu). Type 'help; ' or '\h' for help. Type '\c' to clear the buffer. SHOW DATABASES. +- -- -- -- -- -- -- -- -- -- -+. Database |. +- -- -- -- -- -- -- -- -- -- -+. We use the mysql monitor client application to connect to the. We connect to the database using the root account. We show all available. SHOW DATABASES statement. CREATE DATABASE mydb. Query OK, 1 row affected (0. We create a new mydb database. We will use this database throughout. CREATE USER user. IDENTIFIED BY '3. Query OK, 0 rows affected (0. USE mydb. Database changed. GRANT ALL ON mydb.* to user. Query OK, 0 rows affected (0. We create a new database user. We grant all privileges to this user. In order to connect to the My. SQL database from the PHP language, we must have. This is a package name for. Debian/Ubuntu Linux. On other derivatives the name might differ. This package. has three modules. They are also called extensions. The generic mysql module is the original PHP API for the My. SQL. database. Our tutorial covers this module. The API is procedural. This module does not provide all the latest features of the newer. My. SQL databases. The My. SQL improved mysqli module is the. My. SQL versions 4. It provides both. APIs. It has several benefits and enhancements. The pdo_mysql, PHP Data Objects module is a database abstraction. PHP applications. This module is beneficial if we write portable. PHP scripts. The following script is a simple PHP script. If this small. script runs OK, we have everything needed installed. Could not connect to server\n". E_USER_ERROR). echo "Connection established\n". We connect to the database and get some info about the My. SQL server. $host = "localhost". These are three variables holding the host name, user name and password. The variables are needed when connecting to the My. SQL database. $r = mysql_connect($host, $user, $pass). We use the mysql_connect() function to connect. The function returns a boolean value indicating. The function has 3 parameters. The first is the host, where. The second and third parameters are the user name. Could not connect to server\n". E_USER_ERROR). echo "Connection established\n". Now we check the $r variable. If it contains a boolean false, the. We call the trigger_error(). The first generic message. The more specific error message generated with the. The mysql_get_server_info() returns the My. SQL server version. The mysql_close() function closes the connection. Closing connection in our case is not necessary. However, it is a good programming practice. On my system, I got the following output. We have a similar script. Could not connect to server\n". E_USER_ERROR). echo "Connection established\n". SELECT VERSION()". Could not execute query: $query\n". E_USER_ERROR). echo "Query: $query executed\n". Version: $row[0]\n". We check for the version of the My. SQL database. This time using. SELECT VERSION()". This is the SQL SELECT statement. It returns the version. The VERSION() is. My. SQL function. The mysql_query() function executes an SQL. This is a SELECT query, so the result is. Could not execute query: $query\n". E_USER_ERROR). echo "Query: $query executed\n". In case of an error we generate an error message. Otherwise. we print the SQL query executed. We fetch a row from the result set. The $row variable. Version: $row[0]\n". We print the data from the array. We know from the nature of our. My. SQL version. $ php version. Connection established. Query: SELECT VERSION() executed. Version: 5. 1. 6. Output of the script on our system. Creating and populating a table. Next we are going to create a database table and fill it with data. Cannot execute query: $query\n". Query: $query executed\n". Could not connect to server\n". E_USER_ERROR). echo "Connection established\n". Cannot select database\n". E_USER_ERROR). echo "Database selected\n". DROP TABLE IF EXISTS Cars". CREATE TABLE Cars(Id INT PRIMARY KEY, Name TEXT. Price INT) ENGINE=Inno. DB". execute_query($query). INSERT INTO Cars VALUES(1,'Audi',5. INSERT INTO Cars VALUES(2,'Mercedes',5. INSERT INTO Cars VALUES(3,'Skoda',9. INSERT INTO Cars VALUES(4,'Volvo',2. INSERT INTO Cars VALUES(5,'Bentley',3. INSERT INTO Cars VALUES(6,'Citroen',2. INSERT INTO Cars VALUES(7,'Hummer',4. INSERT INTO Cars VALUES(8,'Volkswagen',2. In the above code example, we create a Cars table with 8 rows. Cannot execute query: $query\n". Query: $query executed\n". We have created a custom execute_query() function which will. INSERT statement. Before we can work with database tables, we must select a database. A database is selected with a mysql_select_db() function. Cannot select database\n". E_USER_ERROR). echo "Database selected\n". Error handling for the database selection process. DROP TABLE IF EXISTS Cars". The first query drops a Cars table if it already exists. CREATE TABLE Cars(Id INT PRIMARY KEY, Name TEXT. Price INT) ENGINE=Inno. DB". execute_query($query). This is the SQL statement to create the Cars table. INSERT INTO Cars VALUES(1,'Audi',5. A car is inserted into the table. Cannot execute query. In case of an error, we print the error message and. Connection established. Database selected. Query: DROP TABLE IF EXISTS Cars executed. Query: CREATE TABLE Cars(Id INT PRIMARY KEY, Name TEXT. Price INT) ENGINE=Inno. DB executed. Query: INSERT INTO Cars VALUES(1,'Audi',5. Query: INSERT INTO Cars VALUES(2,'Mercedes',5. Query: INSERT INTO Cars VALUES(3,'Skoda',9. Query: INSERT INTO Cars VALUES(4,'Volvo',2. Query: INSERT INTO Cars VALUES(5,'Bentley',3. Query: INSERT INTO Cars VALUES(6,'Citroen',2. Query: INSERT INTO Cars VALUES(7,'Hummer',4. Query: INSERT INTO Cars VALUES(8,'Volkswagen',2. Executing the create_fill. SELECT * FROM Cars. Id | Name | Price |. Audi | 5. 26. 42 |. Mercedes | 5. 71. Skoda | 9. 00. Volvo | 2. 90. 00 |. Bentley | 3. 50. Citroen | 2. 10. Hummer | 4. 14. Volkswagen | 2. 16. The data inserted into the Cars table. Retrieving data. Now that we have inserted some data into the database, we want to. Could not connect to server\n". E_USER_ERROR). echo "Connection established\n". Cannot select database\n". E_USER_ERROR). echo "Database selected\n". SELECT * FROM Cars LIMIT 5". Could not execute query: $query". E_USER_ERROR). echo "Query: $query executed\n". Id'] . " " . $row['Name'] . PHP: mysql_insert_id - Manual. If you insert a data row by using the ON DUPLICATE KEY UPDATE clause in an INSERT- statement, the mysql_insert_id() function will return not the same results as if you directly use LAST_INSERT_ID() in My. SQL. See the following example: < ?// insert a datarow, primary key is auto_increment// value is a unique key$query = "INSERT INTO test (value) VALUES ('test')"; mysql_query( $query ); echo 'LAST_INSERT_ID: ',mysql_query( "SELECT LAST_INSERT_ID()" ),'< br> mysql_insert_id: ',mysql_insert_id(); ?> This will print: LAST_INSERT_ID: 1mysql_insert_id: 1. In this case the function returns the same as the My. SQL- Statement. But see the insert on an existing key: < ?$query = "INSERT INTO test (value) VALUES ('test')ON DUPLICATE KEY UPDATE value = 'test. LAST_INSERT_ID: ',mysql_query( "SELECT LAST_INSERT_ID()" ),'< br> mysql_insert_id: ',mysql_insert_id(); ?> This will print: LAST_INSERT_ID: 2mysql_insert_id: 1. By using the ON DUPLICATE KEY UPDATE clause, only the old datarow will be modified, if the INSERT statement causes a duplicate entry, but the LAST_INSERT_ID() function returns the next auto_increment value for the primary key, which is by the way not set as the next auto_increment value in the database. The mysql_insert_id() function returns the primary key of the old (and changed) data row. For me this is the right operation method, because the LAST_INSERT_ID() function returns a value which is not referenced to a data row at all. Greets from Munich.
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