protected override DbDataReader ExecuteDbDataReader(CommandBehavior behavior)
{
if (ReaderMethodCache.TryGetValue(CommandText, out var cached) == false)
{
var lastDotIndex = CommandText.LastIndexOf('.');
var typeString = CommandText.Substring(0, lastDotIndex);
var type = Assembly.GetExecutingAssembly().GetType(typeString);
var methodString = CommandText.Substring(lastDotIndex + 1);
var methodInfo = type.GetMethod(methodString);
var returnType = methodInfo.ReturnType;
var enumeratorMethodInfo = returnType.GetMethod("GetEnumerator");
var rowType = returnType.GetGenericArguments()[0];
if (IsClrType(Nullable.GetUnderlyingType(rowType) ?? rowType))
{
cached = Tuple.Create(methodInfo, enumeratorMethodInfo, rowType, (PropertyInfo[])null);
}
else
{
cached = Tuple.Create(methodInfo, enumeratorMethodInfo, (Type)null, rowType.GetProperties());
}
ReaderMethodCache.Add(CommandText, cached);
}
var enumerable = cached.Item1.Invoke(null, null);
var enumerator = (IEnumerator)cached.Item2.Invoke(enumerable, null);
return(new FakeDataReader(cached.Item3, cached.Item4, enumerator));
}
/// <summary>
/// EXAMPLE QUERY
/// CREATE INDEX idx_lastname
/// ON Persons(LastName);
/// </summary>
protected override void ParseQuery()
{
// find index of open bracket in create query, where are descriptions of columns
var openBacket = CommandText.IndexOf('(');
// find index of close bracket in create query, where are descriptions of columns
var closeBacket = CommandText.LastIndexOf(')');
if (openBacket == -1 || closeBacket == -1 || openBacket == closeBacket)
{
throw new CreateIndexParse($"Command has incorrect signature. Check brackets.");
}
// get columns name
var commandWords = CommandText?
.Substring(0, openBacket)
.Trim()
.Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
if (commandWords[0].ToLower() != "create")
{
throw new CreateIndexParse($"Command has incorrect signature.");
}
if (commandWords.Length == 5)
{
if (commandWords[2].ToLower() != "index")
{
throw new CreateIndexParse($"Command has incorrect signature.");
}
// find 'ON' into query
if (commandWords[3].ToLower() != "on")
{
throw new CreateIndexParse($"Command has incorrect signature.");
}
TableName = commandWords[4];
IndexName = commandWords[2];
IndexType = IndexType.DenseIndex;
}
else if (commandWords.Length == 6)
{
if (commandWords[3].ToLower() != "index")
{
throw new CreateIndexParse($"Command has incorrect signature.");
}
throw new CreateIndexParse($"Command has not released.");
}
else
{
throw new CreateIndexParse($"Command has incorrect signature.");
}
var columnName = CommandText?
.Substring(openBacket + 1, closeBacket - 1 - openBacket);
if (columnName.Length == 0)
{
throw new CreateIndexParse($"Command has incorrect signature. Can not parse columns name.");
}
TableName = commandWords[2].Trim();
}
protected override void ParseQuery()
{
// find index of open bracket in create query, where are descriptions of columns
var openBacket = CommandText.IndexOf('(');
// find index of close bracket in create query, where are descriptions of columns
var closeBacket = CommandText.LastIndexOf(')');
if (openBacket == -1 || closeBacket == -1 || openBacket == closeBacket)
{
throw new CreateTableParse($"Command has incorrect signature. Check brackets.");
}
// get command words, words befor descriptions of columns
var commandWords = CommandText?
.Substring(0, openBacket)
.Trim()
.Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
if (commandWords.Length != 3)
{
throw new CreateTableParse($"Command has incorrect signature. Check table name.");
}
// set table name and database name if format [dbname].[tableName]
var tableAndDatabaseNames = commandWords[2].Split('.');
if (tableAndDatabaseNames.Length == 2)
{
DatabaseName = tableAndDatabaseNames[0];
TableName = tableAndDatabaseNames[1];
}
else
{
TableName = tableAndDatabaseNames[0];
}
//
Columns = CommandText?
.Substring(openBacket + 1, closeBacket - openBacket - 1)
.Trim()
.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
if (Columns.Length == 0)
{
throw new CreateTableParse($"Command does not have new columns description.");
}
}
public override object ExecuteScalar()
{
if (ScalarMethodCache.TryGetValue(CommandText, out var cached) == false)
{
var lastDotIndex = CommandText.LastIndexOf('.');
var typeString = CommandText.Substring(0, lastDotIndex);
var type = Assembly.GetExecutingAssembly().GetType(typeString);
var methodString = CommandText.Substring(lastDotIndex + 1);
cached = type.GetMethod(methodString);
ScalarMethodCache.Add(CommandText, cached);
}
var value = cached.Invoke(null, null);
return(value ?? DBNull.Value);
}
