MySQL - TINYINT



MySQL TINYINT 数据类型

MySQL 的TINYINT数据类型用于存储范围很小的整数值。它只占用 1 字节(8 位)的存储空间,对于带符号的 TINYINT,可以存储 -128 到 127 的值;对于无符号的 TINYINT,可以存储 0 到 255 的值。

在 MySQL 中定义 TINYINT 列时,默认情况下它被认为是带符号的。这意味着它可以在特定范围内保存正数和负数。此外,可以使用“TINYINT”或“INT1”来定义这样的列,因为它们的工作方式相同。

语法

以下是 MySQL TINYINT 数据类型的语法:

TINYINT(M) [SIGNED | UNSIGNED | ZEROFILL]

示例

首先,让我们使用以下查询创建一个名为tinyint_table的表:

CREATE TABLE tinyint_table ( col1 TINYINT, col2 TINYINT UNSIGNED, col3 TINYINT ZEROFILL );

获得以下输出:

Query OK, 0 rows affected, 1 warning (0.03 sec)

现在,让我们尝试将一些值 (128, 128, 128) 插入这些列,如下所示:

INSERT INTO tinyint_table VALUES (128, 128, 128);

因为插入的值超出范围,所以col1的值会生成错误:

ERROR 1264 (22003): Out of range value for column 'col1' at row 1

接下来,如果我们尝试将负值插入 TINYINT UNSIGNED 列 (“col2”),则会发生错误,因为 UNSIGNED 值不能为负:

INSERT INTO tinyint_table VALUES (127, -120, 128);

显示的错误消息如下:

ERROR 1264 (22003): Out of range value for column 'col2' at row 1

同样,如果我们将 -128 插入 TINYINT ZEROFILL 列 (“col3”),则会生成错误:

INSERT INTO tinyint_table VALUES (127, 128, -128);

输出如下所示:

ERROR 1264 (22003): Out of range value for column 'col3' at row 1

但是,如果我们插入有效范围内的值,则插入操作将成功,如下所示:

INSERT INTO tinyint_table VALUES (127, 128, 128);

上述代码的输出如下:

Query OK, 1 row affected (0.01 sec)

最后,我们可以使用以下 SELECT 查询检索表中存在的所有记录:

SELECT * FROM tinyint_table;

此查询将显示以下结果:

col1 col2 col3
127 128 128

使用客户端程序的 TINYINT 数据类型

我们也可以使用客户端程序创建 TINYINT 数据类型的列。

语法

要通过 PHP 程序创建一个 TINYINT 数据类型的列,我们需要使用mysqli函数query()执行“CREATE TABLE”语句,如下所示:

$sql = 'CREATE TABLE tinyint_table ( col1 TINYINT, col2 TINYINT UNSIGNED, col3 TINYINT ZEROFILL )'; $mysqli->query($sql);

要通过 JavaScript 程序创建一个 TINYINT 数据类型的列,我们需要使用mysql2库的query()函数执行“CREATE TABLE”语句,如下所示:

sql = "CREATE TABLE tinyint_table ( col1 TINYINT, col2 TINYINT UNSIGNED, col3 TINYINT ZEROFILL )"; con.query(sql);

要通过 Java 程序创建一个 TINYINT 数据类型的列,我们需要使用JDBC函数execute()执行“CREATE TABLE”语句,如下所示:

String sql = "CREATE TABLE tinyint_table ( col1 TINYINT, col2 TINYINT UNSIGNED, col3 TINYINT ZEROFILL )"; statement.execute(sql);

要通过 python 程序创建一个 TINYINT 数据类型的列,我们需要使用MySQL Connector/Pythonexecute()函数执行“CREATE TABLE”语句,如下所示:

sql = 'CREATE TABLE tinyint_table (col1 TINYINT, col2 TINYINT UNSIGNED, col3 TINYINT ZEROFILL)' cursorObj.execute(sql)

示例

以下是程序:

$dbhost = 'localhost'; $dbuser = 'root'; $dbpass = 'password'; $dbname = 'TUTORIALS'; $mysqli = new mysqli($dbhost, $dbuser, $dbpass, $dbname); if ($mysqli->connect_errno) { printf("Connect failed: %s", $mysqli->connect_error); exit(); } //printf('Connected successfully.'); $sql = 'CREATE TABLE tinyint_table ( col1 TINYINT, col2 TINYINT UNSIGNED, col3 TINYINT ZEROFILL )'; $result = $mysqli->query($sql); if ($result) { printf("Table created successfully...!\n"); } // insert data into created table $q = " INSERT INTO tinyint_table (col1, col2, col3) VALUES (100, 105, 110)"; if ($res = $mysqli->query($q)) { printf("Data inserted successfully...!\n"); } //now display the table records $s = "SELECT * FROM tinyint_table"; if ($r = $mysqli->query($s)) { printf("Table Records: \n"); while ($row = $r->fetch_assoc()) { printf(" Col_1: %s, Col_2: %s, Col_3: %s", $row["col1"], $row["col2"], $row["col3"]); printf("\n"); } } else { printf('Failed'); } $mysqli->close();

输出

获得的输出如下:

Table created successfully...!
Data inserted successfully...!
Table Records:
 Col_1: 100, Col_2: 105, Col_3: 110          
var mysql = require("mysql2"); var con = mysql.createConnection({ host: "localhost", user: "root", password: "password", }); //Connecting to MySQL con.connect(function (err) { if (err) throw err; // console.log("Connected successfully...!"); // console.log("--------------------------"); sql = "USE TUTORIALS"; con.query(sql); //create a tinyint_table table, that accepts one column of tinyint type. sql = "CREATE TABLE tinyint_table ( col1 TINYINT, col2 TINYINT UNSIGNED, col3 TINYINT ZEROFILL )"; con.query(sql); //insert data into created table sql = "INSERT INTO tinyint_table (col1, col2, col3) VALUES (100, 105, 110)"; con.query(sql); //select datatypes of salary sql = `SELECT DATA_TYPE FROM INFORMATION_SCHEMA.COLUMNS WHERE table_name = 'tinyint_table' AND COLUMN_NAME = 'col2'`; con.query(sql, function (err, result) { if (err) throw err; console.log(result); }); });

输出

生成的输出如下:

[ { DATA_TYPE: 'tinyint' } ]
import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.Statement; public class TinyInt { public static void main(String[] args) { String url = "jdbc:mysql://127.0.0.1:3306/TUTORIALS"; String username = "root"; String password = "password"; try { Class.forName("com.mysql.cj.jdbc.Driver"); Connection connection = DriverManager.getConnection(url, username, password); Statement statement = connection.createStatement(); System.out.println("Connected successfully...!"); //TinyInt data types...!; String sql = "CREATE TABLE tinyint_table ( col1 TINYINT, col2 TINYINT UNSIGNED, col3 TINYINT ZEROFILL )"; statement.execute(sql); System.out.println("column of a TINYINT type created successfully...!"); ResultSet resultSet = statement.executeQuery("DESCRIBE tinyint_table"); while (resultSet.next()){ System.out.println(resultSet.getString(1)+" "+resultSet.getString(2)); } connection.close(); } catch (Exception e) { System.out.println(e); } } }

输出

获得的输出如下所示:

Connected successfully...!
column of a TINYINT type created successfully...!
col1 tinyint
col2 tinyint unsigned
col3 tinyint(3) unsigned zerofill
import mysql.connector # Establishing the connection connection = mysql.connector.connect( host='localhost', user='root', password='password', database='tut' ) # Creating a cursor object cursorObj = connection.cursor() # Create table with Tinyint column sql = ''' CREATE TABLE tinyint_table ( col1 TINYINT, col2 TINYINT UNSIGNED, col3 TINYINT ZEROFILL )''' cursorObj.execute(sql) print("The table is created successfully!") # Insert data into the created table insert_query = "INSERT INTO tinyint_table (col1, col2, col3) VALUES (127, 128, 128);" cursorObj.execute(insert_query) # Commit the changes after the insert operation connection.commit() print("Rows inserted successfully.") # Now display the table records select_query = "SELECT * FROM tinyint_table" cursorObj.execute(select_query) result = cursorObj.fetchall() print("Table Data:") for row in result: print(row) cursorObj.close() connection.close()

输出

上述代码的输出如下:

The table is created successfully!
Rows inserted successfully.
Table Data:
(127, 128, 128)
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