约束失败 - SQLite 3 - Android

Question

我的 SQLite 上有下表。

    StringBuilder createSql = new StringBuilder();
    createSql.append("create table LIBRARY ( ");
    createSql.append("id integer primary key, ");
    createSql.append("title text, ");
    createSql.append("author text, ");
    createSql.append("publisher text, ");
    createSql.append("thumbnailUrl text, ");
    createSql.append("formatType text, ");
    createSql.append("contentUrl text, ");
    createSql.append("publicationType text, ");
    createSql.append("favorite text, ");
    createSql.append("started text, ");
    createSql.append("normalizedTitle text, ");
    createSql.append("downloaded integer, ");
    createSql.append("wasDownloaded text ");
    createSql.append(");");

下面的代码在该表上插入一个值。

public void addLibrary(LibraryItem item) {
    ContentValues row = new ContentValues();
    row.put("title", item.getTitle());
    row.put("author", item.getAuthor());
    row.put("publisher", item.getPublisher());
    row.put("thumbnailUrl", item.getThumbnail());
    row.put("formatType", item.getFormat());
    row.put("contentUrl", item.getContentUrl());
    row.put("publicationType", item.getPublicationType());
    row.put("favorite", item.isFavorite() ? "YES" : "NO");
    row.put("id", item.getItemId());
    row.put("normalizedTitle", StringUtil.normalize(item.getTitle()));
    row.put("downloaded", Calendar.getInstance().getTimeInMillis());
    row.put("wasdownloaded", item.hasContent() ? "YES" : "NO");

    long id = db.insert("LIBRARY", null, row);
    add(id, item.getCategories());
}

但是当执行它时，我收到以下错误。

Error inserting id=255 formatType=null author=null title=A Cabana contentUrl=/sdcard/Digital Editions/A Cabana.pdf publicationType=Livro thumbnailUrl=https://api-dls.homolog.abrildigital.com.br/images/22/android_cover_201103092041.jpg wasdownloaded=NO downloaded=1302631109426 normalizedTitle=A Cabana favorite=NO publisher=null
android.database.sqlite.SQLiteConstraintException: error code 19: constraint failed

怎么了？

Answer 1

您的主键不会自动递增。然后您插入第一行，它有一个键，然后您插入另一行，它有相同的键，但主键不能相同！

然后您正在插入具有指定键的项目，我认为该错误意味着具有该键的项目已经存在。

Answer 2

将您的 createSQL 构建器更改为...

createSql.append("id integer primary key autoincrement, ");

另外。当您进行插入时，您没有设置 id 字段。相反，您应该做的是在函数的顶部进行检查。

if(item.getItemID() == 0)
{
    //Run update here instead.
    //Set the id on the ContentValues here
}
else
{
    //Run insert statement instead.
    //Don't set the id in the ContentValues here.
}