SQLite UPDATE statement gives error: Result: near ".": syntax error. Maybe prefixed columns are not supported

[Veselin Kutsarov]

Hi, at first I would to thank you for the library. It helped me a lot.
I have one question. In the SQL generator for the UPDATE statements you prefix columns with tablename. I'm using SQLite 3 and even in DBBrowser for SQLite it seems that database does not support prefixed columns for UPDATE statements.
I can create own SQLGenerator inheriting yours and to override the GetUpdate method and to clean the prefixes if the Prvoder is SQLite, but I'm not sure if I'm right.

[Paulo Victor Lund]

Can you provide the generated query result?

[Veselin Kutsarov]

I've already made custom SqlGenerator. Just removed prefixed with table name fields on update statement, when provider is SqLite. See GetFieldsUpdate.

  public class PrefixedSqlGenerator<TEntity> : SqlGenerator<TEntity> where TEntity : class
    {
        private static SqlProvider ResolveProvider(ShellSettings shellSettings)
        {
            switch (shellSettings["DatabaseProvider"])
            {
                case "SqlConnection":
                    return SqlProvider.MSSQL;
                case "Sqlite":
                    return SqlProvider.SQLite;
                case "MySql":
                    return SqlProvider.MySQL;
                case "Postgres":
                    return SqlProvider.PostgreSQL;
                default:
                    return SqlProvider.MSSQL;
            }
        }

        public PrefixedSqlGenerator(string tablePrefix, ShellSettings shellSettings)
            : base(ResolveProvider(shellSettings))
        {
            TableName = $"{tablePrefix}{TableName}";
        }

        #region SQLite UPDATE workaround
        private string CallableAppendJoinToUpdate<TBase>(TBase entity, SqlQuery originalBuilder, params Expression<Func<TEntity, object>>[] includes)
        {
            var mi = GetType().GetMethod("AppendJoinToUpdate", BindingFlags.NonPublic | BindingFlags.Instance);
            var gm = mi.MakeGenericMethod(typeof(TBase));
            return gm.Invoke(this, new object[] { entity, originalBuilder, includes }) as string;
        }

        public override SqlQuery GetUpdate(TEntity entity, params Expression<Func<TEntity, object>>[] includes)
        {
            if (Provider != SqlProvider.SQLite)
                return base.GetUpdate(entity, includes);

            var properties = SqlProperties.Where(p =>
                !KeySqlProperties.Any(k => k.PropertyName.Equals(p.PropertyName, StringComparison.OrdinalIgnoreCase)) && !p.IgnoreUpdate).ToArray();
            
            if (!properties.Any())
                throw new ArgumentException("Can't update without [Key]");

            if (HasUpdatedAt)
            {
                var attribute = UpdatedAtProperty.GetCustomAttribute<UpdatedAtAttribute>();
                var offset = attribute.TimeKind == DateTimeKind.Local
                    ? new DateTimeOffset(DateTime.Now)
                    : new DateTimeOffset(DateTime.UtcNow);
                if (attribute.OffSet != 0)
                {
                    offset = offset.ToOffset(TimeSpan.FromHours(attribute.OffSet));
                }

                UpdatedAtProperty.SetValue(entity, offset.DateTime);
            }

            var query = new SqlQuery();

            query.SqlBuilder
                .Append("UPDATE ")
                .Append(TableName)
                .Append(" ");

            if (includes?.Length > 0)
            {
                var joinsBuilder = CallableAppendJoinToUpdate(entity, query, includes);
                query.SqlBuilder.Append("SET ");
                query.SqlBuilder.Append(GetFieldsUpdate(TableName, properties, UseQuotationMarks));
                query.SqlBuilder.Append(joinsBuilder);
            }
            else
            {
                query.SqlBuilder.Append("SET ");
                query.SqlBuilder.Append(GetFieldsUpdate(TableName, properties, UseQuotationMarks));
            }

            query.SqlBuilder.Append(" WHERE ");

            query.SqlBuilder.Append(string.Join(" AND ", KeySqlProperties.Where(p => !p.IgnoreUpdate)
                .Select(p => $"{TableName}.{p.ColumnName} = @{entity.GetType().Name}{p.PropertyName}")));
            
            if (query.Param == null || !(query.Param is Dictionary<string,object> parameters))
                parameters = new Dictionary<string, object>();

            foreach (var metadata in properties.Concat(KeySqlProperties))
                parameters.Add($"{entity.GetType().Name}{metadata.PropertyName}", entity.GetType().GetProperty(metadata.PropertyName).GetValue(entity, null));
            
            query.SetParam(parameters);

            return query;
        }

        private string GetFieldsUpdate(string tableName, IEnumerable<SqlPropertyMetadata> properties, bool useMarks)
        {
            //return String.Join(", ", properties
            //    .Select(p => $"{tableName}.{(useMarks ? p.ColumnName : p.CleanColumnName)} = @{p.PropertyInfo.ReflectedType.Name}{p.PropertyName}"));
            return String.Join(", ", properties
                .Select(p => $"{(useMarks ? p.ColumnName : p.CleanColumnName)} = @{p.PropertyInfo.ReflectedType.Name}{p.PropertyName}"));
        }
        #endregion
    }

[0-NightStalker-0]

Same happened on Postgres and this fix also works for me.

[Harshit Gindra]

#164

[Serge K]

@harshitgindra Thank you!

Published in 1.16.1