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尝试在从XML文件中提取后将SQL值插入数据库，但在嵌入Python代码中的insert语句之后似乎没有出现在数据库中。如果不包含SQL部分，则按预期打印条目。我的Python环境（Anaconda Navigator）没有出现错误，所以完全没有处理查询的方式，但没有输入任何内容！我尝试了一个基本的select语句来显示表，但是返回一个空表。

选择查询

%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:），则连接将提交您所做的任何更改（如果发生错误，则将其回滚）。
明确关闭连接也是一种很好的做法。

Answer 2

看起来您忘记提交并关闭连接。您需要调用这两个函数才能正确关闭连接并将您已完成的工作保存到数据库中。

conn.commit()
conn.close()

在Python中成功的SQLite语句之后没有插入数据

2 个答案: