PostgreSQL有效地处理数据序列化和反序列化的方法

CREATE TABLE simple_data (
    id INTEGER,
    price FLOAT,
    is_active BOOLEAN
);

INSERT INTO simple_data (id, price, is_active)
VALUES (1, 45.67, TRUE);

SELECT * FROM simple_data;

CREATE TABLE string_data (
    short_char CHAR(5),
    variable_char VARCHAR(50),
    long_text TEXT
);

INSERT INTO string_data (short_char, variable_char, long_text)
VALUES ('abcde', 'This is a longer string', 'This is a very long text that can span multiple lines.');

SELECT * FROM string_data;

CREATE TABLE date_time_data (
    event_date DATE,
    start_time TIME,
    creation_timestamp TIMESTAMP
);

INSERT INTO date_time_data (event_date, start_time, creation_timestamp)
VALUES ('2023-09-15', '13:45:00', '2023-09-15 13:45:00');

SELECT * FROM date_time_data;

CREATE TABLE array_data (
    int_array INTEGER[],
    text_array TEXT[]
);

INSERT INTO array_data (int_array, text_array)
VALUES ('{1, 2, 3}', '{"apple", "banana", "cherry"}');

SELECT * FROM array_data;

CREATE TYPE person_type AS (
    name VARCHAR(50),
    age INTEGER
);

CREATE TABLE persons (
    data person_type
);

INSERT INTO persons (data)
VALUES (ROW('John Doe', 30));

SELECT * FROM persons;

SELECT TO_CHAR(45.67, '999.99'), TO_NUMBER('123') AS num, TO_DATE('2023-09-15', 'YYYY-MM-DD') AS date;

SELECT ARRAY_TO_STRING('{1, 2, 3}', ',') AS array_to_string, STRING_TO_ARRAY('apple,banana,cherry', ',') AS string_to_array;

CREATE TABLE json_data (
    data JSONB
);

INSERT INTO json_data (data)
VALUES ('{"name": "John", "age": 30}');

SELECT JSON_BUILD_OBJECT('name', 'Jane', 'age', 25) AS built_json, JSON_EXTRACT_PATH(data, 'name') AS extracted_name FROM json_data;

import psycopg2

conn = psycopg2.connect(database="your_database", user="your_user", password="your_password", host="your_host", port="your_port")
cursor = conn.cursor()

# 执行查询
cursor.execute("SELECT * FROM your_table")

# 获取结果
results = cursor.fetchall()

for row in results:
    # 处理每行数据，根据数据类型进行反序列化
    id = row[0]  # 假设第一列为整数类型
    name = row[1]  # 假设第二列为字符串类型

# 关闭连接
cursor.close()
conn.close()

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class PostgreSQLExample {
    public static void main(String[] args) {
        String url = "jdbc:postgresql://your_host:your_port/your_database";
        String user = "your_user";
        String password = "your_password";

        try (Connection connection = DriverManager.getConnection(url, user, password)) {
            String sql = "SELECT * FROM your_table";
            PreparedStatement statement = connection.prepareStatement(sql);
            ResultSet resultSet = statement.executeQuery();

            while (resultSet.next()) {
                int id = resultSet.getInt("id");  // 假设第一列为整数类型
                String name = resultSet.getString("name");  // 假设第二列为字符串类型
            }

            resultSet.close();
            statement.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

import psycopg2
from Crypto.Cipher import AES

class CustomSerializer:
    def __init__(self, key):
        self.cipher = AES.new(key, AES.MODE_ECB)

    def serialize(self, value):
        # 加密逻辑
        padded_value = self.pad(value)
        encrypted_value = self.cipher.encrypt(padded_value)
        return encrypted_value

    def deserialize(self, encrypted_value):
        # 解密逻辑
        decrypted_value = self.cipher.decrypt(encrypted_value)
        unpadded_value = self.unpad(decrypted_value)
        return unpadded_value

    def pad(self, value):
        block_size = 16
        padding_length = block_size - len(value) % block_size
        padding = bytes([padding_length] * padding_length)
        return value + padding

    def unpad(self, value):
        padding_length = value[-1]
        return value[:-padding_length]

conn = psycopg2.connect(database="your_database", user="your_user", password="your_password", host="your_host", port="your_port")
cursor = conn.cursor()

serializer = CustomSerializer(b'your_secret_key')

cursor.execute("SELECT encrypted_column FROM your_table")
results = cursor.fetchall()

for row in results:
    encrypted_value = row[0]
    decrypted_value = serializer.deserialize(encrypted_value)
    # 处理解密后的数据

cursor.close()
conn.close()

import psycopg2
import random

conn = psycopg2.connect(database="your_database", user="your_user", password="your_password", host="your_host", port="your_port")
cursor = conn.cursor()

data = [(random.randint(1, 100), f'Name {i}') for i in range(1000)]

# 批量插入
cursor.executemany("INSERT INTO your_table (id, name) VALUES (%s, %s)", data)

conn.commit()
cursor.close()
conn.close()

CREATE TABLE tree_nodes (
    id INTEGER,
    parent_id INTEGER,
    name VARCHAR(50)
);

INSERT INTO tree_nodes (id, parent_id, name)
VALUES (1, NULL, 'Root'),
       (2, 1, 'Child 1'),
       (3, 1, 'Child 2'),
       (4, 2, 'Grandchild 1'),
       (5, 3, 'Grandchild 2');

-- 递归查询获取完整的树形结构
WITH RECURSIVE tree AS (
    SELECT id, parent_id, name, 1 AS level
    FROM tree_nodes
    WHERE parent_id IS NULL
    UNION ALL
    SELECT t.id, t.parent_id, t.name, tree.level + 1 AS level
    FROM tree_nodes t
    JOIN tree ON t.parent_id = tree.id
)
SELECT * FROM tree;

CREATE TABLE large_objects (
    id SERIAL PRIMARY KEY,
    data BYTEA
);

-- 插入二进制数据
INSERT INTO large_objects (data)
VALUES (DECODE('hex_data', 'hex'));  -- 将十六进制数据转换为二进制

-- 检索二进制数据
SELECT data FROM large_objects;

CREATE TABLE sales (
    sale_id SERIAL PRIMARY KEY,
    sale_date DATE,
    amount DECIMAL(10, 2)
)
PARTITION BY RANGE (sale_date);

CREATE TABLE sales_2023_q1 PARTITION OF sales
FOR VALUES FROM ('2023-01-01') TO ('2023-03-31');

CREATE TABLE sales_2023_q2 PARTITION OF sales
FOR VALUES FROM ('2023-04-01') TO ('2023-06-30');

-- 插入示例数据
INSERT INTO sales (sale_date, amount)
VALUES ('2023-02-15', 100.00), ('2023-05-20', 200.00);