在 Python 内成功的 SQLite 语句后没有插入数据

Question

试图在从 XML 文件中提取后将 SQL 值插入数据库，但是 none 似乎在 Python 代码中嵌入插入语句后出现在数据库中。如果不包含 SQL 部分，条目将按预期打印。我在 Python 环境 (Anaconda Navigator) 中没有收到错误，因此完全不知道如何处理查询，但没有输入任何内容！我尝试了一个基本的 select 语句来显示 table，但是返回一个空的 table。

Select查询

%sql SELECT * FROM publication;

主要Python代码

import sqlite3
con = sqlite3.connect("publications.db")
cur = con.cursor()

from xml.dom import minidom

xmldoc = minidom.parse("test.xml")

#loop through <pub> tags to find number of pubs to grab
root = xmldoc.getElementsByTagName("root")[0]
pubs = [a.firstChild.data for a in root.getElementsByTagName("pub")]
num_pubs = len(pubs)
count = 0

while(count < num_pubs):

    #get data from each <pub> tag
    temp_pub = root.getElementsByTagName("pub")[count]
    temp_ID = temp_pub.getElementsByTagName("ID")[0].firstChild.data
    temp_title = temp_pub.getElementsByTagName("title")[0].firstChild.data
    temp_year = temp_pub.getElementsByTagName("year")[0].firstChild.data
    temp_booktitle = temp_pub.getElementsByTagName("booktitle")[0].firstChild.data
    temp_pages = temp_pub.getElementsByTagName("pages")[0].firstChild.data
    temp_authors = temp_pub.getElementsByTagName("authors")[0]
    temp_author_array = [a.firstChild.data for a in temp_authors.getElementsByTagName("author")]
    num_authors = len(temp_author_array)
    count = count + 1


    #process results into sqlite
    pub_params = (temp_ID, temp_title)
    cur.execute("INSERT INTO publication (id, ptitle) VALUES (?, ?)", pub_params)
    journal_params = (temp_booktitle, temp_pages, temp_year)
    cur.execute("INSERT INTO journal (jtitle, pages, year) VALUES (?, ?, ?)", journal_params)
    x = 0
    while(x < num_authors):
        cur.execute("INSERT OR IGNORE INTO authors (name) VALUES (?)", (temp_author_array[x],))
        x = x + 1

    #display results
    print("\nEntry processed: ", count)
    print("------------------\nPublication ID: ", temp_ID)
    print("Publication Title: ", temp_title)
    print("Year: ", temp_year)
    print("Journal title: ", temp_booktitle)
    print("Pages: ", temp_pages)
    i = 0
    print("Authors: ")
    while(i < num_authors):
        print("-",temp_author_array[i])
        i = i + 1



print("\nNumber of entries processed: ", count)

SQL 查询

%%sql
DROP TABLE IF EXISTS publication;
CREATE TABLE publication(
    id INT PRIMARY KEY NOT NULL,
    ptitle VARCHAR NOT NULL
);

/* Author Entity set and writes_for relationship */
DROP TABLE IF EXISTS authors;
CREATE TABLE authors(
    name VARCHAR(200) PRIMARY KEY NOT NULL,
    pub_id INT,
    pub_title VARCHAR(200),
    FOREIGN KEY(pub_id, pub_title) REFERENCES publication(id, ptitle)
);

/* Journal Entity set and apart_of relationship */
DROP TABLE IF EXISTS journal;
CREATE TABLE journal(
    jtitle VARCHAR(200) PRIMARY KEY NOT NULL,
    pages INT,
    year INT(4),
    pub_id INT,
    pub_title VARCHAR(200),
    FOREIGN KEY(pub_id, pub_title) REFERENCES publication(id, ptitle)
);

/*  Wrote relationship b/w journal & authors */
DROP TABLE IF EXISTS wrote;
CREATE TABLE wrote(
    name VARCHAR(100) NOT NULL,
    jtitle VARCHAR(50) NOT NULL,
    PRIMARY KEY(name, jtitle),
    FOREIGN KEY(name) REFERENCES authors(name),
    FOREIGN KEY(jtitle) REFERENCES journal(jtitle)  
);

Answer 1

您似乎忘记提交和关闭连接。您需要调用这两个函数才能正确关闭连接并将所做的工作保存到数据库中。

conn.commit()
conn.close()

Answer 2

您需要调用 con.commit() 才能将数据提交到数据库。如果您将连接用作上下文管理器 (with con:)，连接将提交您所做的任何更改（如果出现错误，则将它们回滚）。
显式关闭连接也是一个好习惯。

在 Python 内成功的 SQLite 语句后没有插入数据

No data inserted after successful SQLite statement within Python

python

xml

sqlite

minidom