Question

在SQLite中没有INSERT OR REPLACE INTO或PRIMARY KEY的情况下，有没有可能使用UNIQUE的方法？

我想更新表中的值（如果不存在4个参数与之匹配的值），我想插入一个新行。但是这4个参数不是PRIMARY KEY或UNIQUE（可以重复，但四个是唯一的）。

我尝试使用WHERE，但是INSERT不允许这样做。同样，仅UPDATE不会添加新行。

cur.execute('''INSERT OR REPLACE INTO FileNameStatus
    (FileName, Delivery, SW, FuncName, 
    LinkModDate, ExtSrcModDate, ExtSrcModifier,
    ExtAttModDate, ExtAttModifier, Error, Warning)
    VALUES (?, ?, ?, ?, ? ,? ,? ,? ,? ,? ,?)
    WHERE FileName = :file AND Delivery = :dvry AND SW = :sw AND FuncName = :func''',
    (eachRow, {"file": eachRow[0], "dvry": eachRow[1], "sw": eachRow[2], "func": eachRow[3]},
    ))

是否可以使用SQLite？

Answer 1

相反，您可以做的是

执行查询以检查是否存在具有4个参数的元组

    QUERY = "query to select the 4 fields"
    cursor.execute(QUERY, params)
#if cursor row count is > 0 then you have the fields present in the database and you can update
#if it is == 0, then you know that they don't exist and you can insert

Answer 2

您可以使用EXISTS来检查值是否已经存在：

INSERT INTO FileNameStatus(FileName, Delivery, SW, FuncName, 
    LinkModDate, ExtSrcModDate, ExtSrcModifier,ExtAttModDate, ExtAttModifier, Error, Warning)
SELECT ?, ?, ?, ?, ? ,? ,? ,? ,? ,? ,?
WHERE NOT EXISTS(SELECT 1 
                 FROM FileNameStatus
                 WHERE FileName = :file AND Delivery = :dvry 
                   AND SW = :sw AND FuncName = :func)

Answer 3

我决定添加一个查询以检查数据是否已经存在，如下所示：

    for eachRow in data:
        cur.execute('''SELECT FileName, Delivery, SW, FuncName
                    FROM FileNameStatus
                    WHERE FileName = :file AND Delivery = :dvry AND SW = :sw AND FuncName = :func''',
                    {"file": eachRow[0], "dvry": eachRow[1], "sw": eachRow[2], "func": eachRow[3]})

        row = cur.fetchone()
        if row is None: # row not exist
            cur.execute('''INSERT INTO FileNameStatus
                        (FileName, Delivery, SW, FuncName, LinkModDate, ExtSrcModDate, ExtSrcModifier,
                        ExtAttModDate, ExtAttModifier, Error, Warning)
                        VALUES (?, ?, ?, ?, ? ,? ,? ,? ,? ,? ,?)''',
                        eachRow)
        else: # row exist, just update
            cur.execute('''UPDATE FileNameStatus
                            SET FileName = :file, Delivery = :drvy, SW = :sw, FuncName = :func,
                            LinkModDate = :ld, ExtSrcModDate = :sd, ExtSrcModifier = :sm,
                            ExtAttModDate = :ad, ExtAttModifier = :am, Error = :err, Warning = :warn
                            WHERE FileName = :file AND Delivery = :drvy AND SW = :sw AND FuncName = :func;''',
                        {"file": eachRow[0], "drvy": eachRow[1], "sw": eachRow[2], "func": eachRow[3],
                         "ld": eachRow[4], "sd": eachRow[5], "sm": eachRow[6],
                         "ad": eachRow[7], "am": eachRow[8], "err": eachRow[9], "warn": eachRow[10]})
    # apply the changes
    conn.commit()

有没有可能在没有UNIQUE或PRIMARY KEY值的情况下使用INSERT或REPLACE？

3 个答案: