MySQL is a database system used on the web.
MySQL is ideal for both small and large applications.
MySQL is very fast, reliable, and easy to use.
MySQL uses standard SQL.
The CREATE TABLE statement is used to create a table in MySQL.
You can select all columns using the syntax: SELECT * FROM table_name.
It limits the stored data to positive numbers and zero.
The mysqli_multi_query() function is used to execute multiple SQL statements.
You can use the property $conn->insert_id after performing the INSERT query.
MySQLi extension and PDO (PHP Data Objects).
It will echo 'New records created successfully'.
It ensures that each row must contain a value for that column, disallowing null values.
It sets a default value that is added when no other value is passed for that column.
The prepare method is used to prepare an SQL statement for execution, allowing for parameterized queries.
Improved.
You can use the LIMIT clause with OFFSET: $sql = 'SELECT * FROM Orders LIMIT 10 OFFSET 15'; or use a shorter syntax: $sql = 'SELECT * FROM Orders LIMIT 15, 10';.
$sql = "INSERT INTO MyGuests (firstname, lastname, email) VALUES ('John', 'Doe', 'john@example.com')";
The LIMIT clause is used to specify the number of records to return, making it easier to code multi-page results and improving performance on large tables.
ORDER BY lastname
PDO works with 12 different database systems.
It will echo 'Error: ' followed by the SQL statement and the error message.
fetch_assoc()
SELECT column_name(s) FROM table_name ORDER BY column_name(s) ASC|DESC.
$row = $result->fetch_assoc();
A query can return a record set containing specific information from the database.
The query selects all the data in the 'LastName' column from the 'Employees' table.
<?php $servername = 'localhost'; $username = 'username'; $password = 'password'; $conn = new mysqli($servername, $username, $password); if ($conn->connect_error) { die('Connection failed: ' . $conn->connect_error); } echo 'Connected successfully'; ?>
The four types are: i - integer, d - double, s - string, b - BLOB.
The UPDATE statement is used to update existing records in a table.
echo "Error: " . $sql . "<br>" . $conn->error;
The AUTO_INCREMENT field automatically generates a unique ID for each new record inserted into the table.
The ORDER BY clause sorts the records in ascending order by default.
It will echo 'New record created successfully. Last inserted ID is: ' followed by the last inserted ID.
$conn->close();
You can select specific columns using the syntax: SELECT column_name(s) FROM table_name.
The DELETE statement is used to delete records from a table.
$sql = "SELECT id, firstname, lastname FROM MyGuests WHERE lastname ='Doe'";
You can use the SQL query: $sql = 'SELECT * FROM Orders LIMIT 30';
It checks if there are any rows returned from the query.
The SQL query must be quoted in PHP.
SELECT column_name(s) FROM table_name WHERE column_name operator value.
An example is: SELECT id, firstname, lastname FROM MyGuests WHERE lastname = 'Doe'.
You can display the results on a page or put them in an HTML table.
The code echoes the number of records updated successfully using `$stmt->rowCount() . ' records UPDATED successfully';`.
MySQL is developed, distributed, and supported by Oracle Corporation.
$sql = "CREATE TABLE MyGuests ( id INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY, firstname VARCHAR(30) NOT NULL, lastname VARCHAR(30) NOT NULL, email VARCHAR(50), reg_date TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP )";
Specifying the type of data helps minimize the risk of SQL injections.
UPDATE table_name SET column1 = value, column2 = value2, ... WHERE some_column = some_value
The table being created is named 'MyGuests'.
It will display 'Error creating table: ' followed by the error message.
There are five columns specified: 'id', 'firstname', 'lastname', 'email', and 'reg_date'.
The WHERE clause is used to filter records and extract only those that fulfill a specified condition.
To sort the result set by one or more columns.
id, firstname, lastname
The word NULL must not be quoted.
The while() loop is used to loop through the result set and output the data from the id, firstname, and lastname columns.
An SQL statement template is created, sent to the database, parsed, compiled, and optimized, but not executed.
If there is an error, it echoes 'Error updating record: ' followed by the error message.
The SELECT statement is used to select data from one or more tables.
echo "New record created successfully";
The ORDER BY clause is used to sort the result set in ascending or descending order.
One type must be provided for each parameter.
0 results
Using a while loop with $row = $result->fetch_assoc() to fetch each row as an associative array.
TIMESTAMP
String values inside the SQL query must be quoted.
You should check for connection errors using if ($conn->connect_error).
MySQL compiles on a number of platforms.
Parameters are unspecified values in the SQL statement template, labeled with '?'.
$sql = "DELETE FROM MyGuests WHERE id=3"; if ($conn->query($sql) === TRUE) { echo "Record deleted successfully"; } else { echo "Error deleting record: " . $conn->error; }
You can concatenate multiple INSERT statements into a single string and pass it to mysqli_multi_query().
You use the bind_param method, specifying the types of the parameters followed by the variables to bind.
OFFSET allows you to skip a specified number of records before starting to return records from the query.
It will echo 'Error: ' followed by the SQL query and the error message from the connection.
It sets the PDO error mode to exception, allowing for error handling through exceptions.
$sql = "SELECT id, firstname, lastname FROM MyGuests";
A prepared statement is a feature used to execute the same (or similar) SQL statements repeatedly with high efficiency.
The code snippet is used to update a record in a MySQL database.
A query is a question or a request made to a database for specific information.
The connection will be closed automatically.
It automatically generates a unique id for each new record in the table.
Table MyGuests created successfully
It automatically increases the value of the field by 1 each time a new record is added.
When using OFFSET, the syntax is 'LIMIT number OFFSET number', while using a comma reverses the numbers: 'LIMIT offset, count'.
if ($result->num_rows > 0) { ... }
Numeric values must not be quoted.
echo "<table><tr><th>ID</th><th>Name</th></tr>"; ... echo "</table>";
It checks if there are any results returned from the query.
echo "id: " . $row["id"] . " - Name: " . $row["firstname"] . " " . $row["lastname"] . "<br>";
The question mark (?) is used as a placeholder for substituting in an integer, string, double, or blob value.
DELETE FROM table_name WHERE some_column = some_value.
The INSERT INTO statement is used to add new records to a MySQL table.
An example of a table is the 'MyGuests' table.
$sql = "SELECT id, firstname, lastname FROM MyGuests";
The query selects the id, firstname, and lastname columns from the MyGuests table.
$result is the variable that stores the resulting data from the query.
You prepare a statement using `$stmt = $conn->prepare($sql);`.
echo "0 results";
echo "0 results";
The message displayed is 'Record updated successfully'.
The bind_param() function binds the parameters to the SQL query and specifies the types of data that the parameters are.
$firstname = 'Mary'; $lastname = 'Moe'; $email = 'mary@example.com';
It is used to uniquely identify the rows in a table, ensuring that the value is unique for each record.
It executes the prepared statement with the bound parameters.
It closes the prepared statement and frees up the resources associated with it.
<?php $servername = 'localhost'; $username = 'username'; $password = 'password'; $conn = new mysqli($servername, $username, $password); if ($conn->connect_error) { die('Connection failed: ' . $conn->connect_error); } $sql = 'CREATE DATABASE myDB'; if ($conn->query($sql) === TRUE) { echo 'Database created successfully'; } else { echo 'Error creating database: ' . $conn->error; } $conn->close(); ?>
It executes the prepared statement, applying the update to the database.
It involves two main steps: Prepare, where an SQL statement template is created and sent to the database with unspecified parameters, and Execute, where values are bound to the parameters and the statement is executed.
Yes, the application can execute the prepared statement multiple times with different values.
To sort the records in descending order, use the DESC keyword.
PDO makes it easier to switch to another database by only requiring changes to the connection string and a few queries.
You call the execute method on the prepared statement object.
Yes, after the data type, you can specify other optional attributes for each column.
$firstname = 'Julie'; $lastname = 'Dooley'; $email = 'julie@example.com';
$row = $result->fetch_assoc();
If there is an error, it catches the exception and echoes the SQL statement along with the error message.
The SQL command used is 'UPDATE MyGuests SET lastname ='Doe' WHERE id= 2'.
'sss' indicates that all three parameters are strings.
'sss' indicates that all three parameters being bound are strings.
The message '0 results' is displayed.
The SQL command used is `UPDATE MyGuests SET lastname ='Doe' WHERE id= 2`.
$result = $conn->query($sql);
'Database created successfully'
The message 'Error creating database: ' followed by the error details will be displayed.
The data type specifies what type of data the column can hold.
The code executes an INSERT command to add a new guest to the MyGuests table.
The function num_rows() checks if there are more than zero rows returned.
MySQL is free to download and use.
If the connection fails, it executes 'die' with a message indicating the connection failed.
The fetch_assoc() function puts all the results into an associative array.
'CREATE DATABASE myDB'
You create a connection using the mysqli constructor with parameters for server name, username, password, and database name.
