public static SurlyTableResponse GetTable(this SurlyDatabase database, string tableName)
{
var table = database.Tables.SingleOrDefault(x => x.Name == tableName.ToUpper());
if (table != null)
{
return new SurlyTableResponse {
Table = table
}
}
;
var projection = SurlyProjections.GetInstance().Projections
.SingleOrDefault(x => x.ProjectionName == tableName.ToUpper());
if (projection != null)
{
return(new SurlyTableResponse
{
Table = new SurlyTable
{
Name = projection.ProjectionName,
Schema = projection.AttributeNames,
Tuples = projection.Tuples,
},
IsProjection = true,
HideIndexes = projection.HideIndex
});
}
WriteLine($"\n\t{tableName.ToUpper()} was not found.", Red);
return(null);
}
public static void DestroyTable(this SurlyDatabase database, string tableName, string line)
{
var tableResponse = database.GetTable(tableName);
if (tableResponse.IsProjection)
{
var projection = SurlyProjections.GetInstance().Projections.Single(x => x.ProjectionName == tableName);
SurlyProjections.GetInstance().Projections.Remove(projection);
}
else
{
database.Tables.Remove(tableResponse.Table);
}
WriteLine($"\n\tDestroyed {tableName.ToUpper()}", Green);
}
public static void Select(this SurlyDatabase database, string query)
{
_resultSet = new LinkedList <LinkedList <SurlyAttribute> >();
string tableName, conditions, projectionName = null;
var printProjection = false;
try
{
try
{
projectionName = new Regex("(\\w+) = select", RegexOptions.IgnoreCase)
.Match(query)
.Groups[1]
.Captures[0]
.ToString()
.ToUpper();
}
catch (Exception)
{
printProjection = true;
}
tableName = new Regex("select (\\w+) where", RegexOptions.IgnoreCase)
.Match(query)
.Groups[1]
.Captures[0]
.ToString()
.ToUpper();
conditions = new Regex("where (.+);", RegexOptions.IgnoreCase)
.Match(query)
.Groups[1]
.Captures[0]
.ToString()
.ToUpper();
}
catch (Exception)
{
WriteLine("Invalid SELECT syntax, please see help", Red);
return;
}
var tableResponse = database.GetTable(tableName);
if (tableResponse.Table == null)
{
WriteLine($"{tableName.ToUpper()} not found.", Red);
return;
}
if (!printProjection &&
SurlyProjections.GetInstance().Projections.Any(x => x.ProjectionName.ToUpper() == projectionName?.ToUpper()))
{
WriteLine($"\n\t{projectionName?.ToUpper()} already exists, please choose a different name", Red);
return;
}
var conditionSteps = conditions.Split(' ').ToList();
tableResponse.Table.Tuples.ToList().ForEach(tableRow =>
{
var valid = OperatorHelper.Chain(tableRow, true, conditionSteps.ToArray(), 0);
if (valid)
{
var trimmedRow = new LinkedList <SurlyAttribute>(tableRow);
var rowId = trimmedRow.SingleOrDefault(x => x.Name == "Id");
trimmedRow.Remove(rowId);
_resultSet.AddLast(trimmedRow);
}
});
if (_resultSet.Count == 0)
{
WriteLine("\n\tQuery yielded no results.", Yellow);
return;
}
var schema = new LinkedList <SurlyAttributeSchema>(tableResponse.Table.Schema);
var id = schema.SingleOrDefault(x => x.Name == "Id");
schema.Remove(id);
if (printProjection)
{
var response = new SurlyTableResponse
{
Table = new SurlyTable
{
Schema = schema,
Name = "Results",
Tuples = _resultSet
},
//HideIndexes = true
};
database.PrintTables(new List <SurlyTableResponse> {
response
});
return;
}
SurlyProjections.GetInstance().Projections.AddLast(new SurlyProjection
{
AttributeNames = schema,
HideIndex = true,
ProjectionName = projectionName,
TableName = tableResponse.Table.Name,
Tuples = _resultSet
});
WriteLine($"\n\t{projectionName.ToUpper()} build successful.", Green);
}
