async Task WriteCellAsync(object cell)
{
string value;
if (cell == DBNull.Value)
{
value = "NULL";
}
else if (cell is bool)
{
value = cell.ToString().ToLower();
}
else if (cell is string ||
cell is Guid ||
cell is DateTime ||
cell is DateTimeOffset ||
cell is TimeSpan)
{
value = $"'{cell}'";
}
else if (cell is byte[])
{
var binary = (byte[])cell;
value = "0x" + string.Join("", binary.Select(b => Convert.ToString(b, 16)));
}
else
{
value = cell.ToString();
}
await InnerWriter.WriteAsync(value);
}
async Task WriteRecordAsync(IDataRecord record, int[] indexies)
{
var first = true;
foreach (var i in indexies)
{
if (!first)
{
await InnerWriter.WriteAsync(",");
}
await WriteCellAsync(record[i]);
first = false;
}
}
async Task WriteColumnsAsync(IReadOnlyList <DbColumn> columns, int[] indexies)
{
var first = true;
foreach (var i in indexies)
{
if (!first)
{
await InnerWriter.WriteAsync(",");
}
var column = columns[i];
await InnerWriter.WriteAsync(column.ColumnName);
first = false;
}
}
public async Task WriteAllAsync(DbDataReader reader)
{
var columns = reader.GetColumnSchema();
var indexies = GetOutputColumnIndexies(columns);
while (await reader.ReadAsync())
{
await InnerWriter.WriteAsync($"INSERT INTO {Options.TableName} (");
await WriteColumnsAsync(columns, indexies);
await InnerWriter.WriteAsync(") VALUES (");
await WriteRecordAsync(reader, indexies);
await InnerWriter.WriteLineAsync(");");
}
}