private async Task <IReadOnlyList <IDatabaseColumn> > LoadColumnsAsyncCore(ISqliteDatabasePragma pragma, Identifier viewName, CancellationToken cancellationToken)
{
IEnumerable <Pragma.Query.pragma_table_info> tableInfos;
try
{
// When the view is invalid, this may throw an exception so we catch it.
// This does mean that we are in a partial state, but if the definition is corrected
// and the view is queried again then we'll end up with something correct.
tableInfos = await pragma.TableInfoAsync(viewName, cancellationToken).ConfigureAwait(false);
}
catch (SqliteException ex) when(ex.SqliteErrorCode == SqliteError)
{
return(Array.Empty <IDatabaseColumn>());
}
if (tableInfos.Empty())
{
return(Array.Empty <IDatabaseColumn>());
}
var result = new List <IDatabaseColumn>();
foreach (var tableInfo in tableInfos)
{
if (tableInfo.name == null)
{
continue;
}
var columnName = tableInfo.name;
var columnTypeName = tableInfo.type;
if (columnTypeName.IsNullOrWhiteSpace())
{
columnTypeName = await GetTypeofColumnAsync(viewName, columnName, cancellationToken).ConfigureAwait(false);
}
var affinity = AffinityParser.ParseTypeName(columnTypeName);
var columnType = new SqliteColumnType(affinity);
var defaultValue = !tableInfo.dflt_value.IsNullOrWhiteSpace()
? Option <string> .Some(tableInfo.dflt_value)
: Option <string> .None;
var column = new DatabaseColumn(columnName, columnType, !tableInfo.notnull, defaultValue, Option <IAutoIncrement> .None);
result.Add(column);
}
return(result);
}
/// <summary> /// Gets the type affinity of a given type name. /// </summary> /// <param name="typeName">A type name.</param> /// <returns>A type affinity.</returns> protected static SqliteTypeAffinity GetAffinity(string typeName) => AffinityParser.ParseTypeName(typeName);
