C＃Sqlite用DataTable抛出ConstraintException [英] C# Sqlite throwing ConstraintException with DataTable

问题描述

我正在使用C＃/ Mono来访问Sqlite数据库。

I'm using C#/Mono to access a Sqlite db.

以下查询在任何数据库应用程序中都可以正常工作，但是当我尝试加载结果时，DataTable会持续抱怨。

The following query works fine in any database app, but DataTable keeps complaining when I try to load the results.

这是一个片段

    cmd.CommandText = @"SELECT 
                          sectors.name AS sector_name,
                          domains.name AS domain_name
                        FROM
                          sectors_domains
                          INNER JOIN domains ON (sectors_domains.domain = domains.id)
                          INNER JOIN sectors ON (sectors_domains.sector = sectors.id)";

    using (var rdr = cmd.ExecuteReader())
    {
        using (DataTable dt = new DataTable())
        {
            dt.load(rdr)
        }
    }

这会抛出一个错误：

ConstraintException: Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints.

正在选择的字段（即相应表中的两个.name字段）都被限制为唯一，非空。

The fields being selected (ie, both .name fields in the respective tables) are constrained as Unique and Non-null.

推荐答案

尝试加载数据的其他方法。 （免责声明：我没有尝试过）

Try a different approach to loading the data. (Disclaimer: I haven't tried this)

DataTable dataTable;
cmd.CommandText = @"SELECT 
    sectors.name AS sector_name,
    domains.name AS domain_name
    FROM sectors_domains
    INNER JOIN domains ON (sectors_domains.domain = domains.id)
    INNER JOIN sectors ON (sectors_domains.sector = sectors.id)";


// Create data adapter
SQLiteDataAdapter da = new SQLiteDataAdapter(cmd);

// Populate dataTable based on DB query
da.Fill(dataTable);
da.Dispose();

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