/
SqliteExpression.cs
92 lines (81 loc) · 3.17 KB
/
SqliteExpression.cs
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using System;
using System.Collections.Generic;
using System.Linq.Expressions;
namespace ServiceStack.OrmLite.Sqlite
{
public class SqliteExpression<T> : SqlExpression<T>
{
public SqliteExpression(IOrmLiteDialectProvider dialectProvider)
: base(dialectProvider)
{
}
protected override object VisitColumnAccessMethod(MethodCallExpression m)
{
List<object> args = this.VisitExpressionList(m.Arguments);
var quotedColName = Visit(m.Object);
if (!IsSqlClass(quotedColName))
quotedColName = ConvertToParam(quotedColName);
string statement;
if (m.Method.Name == nameof(string.ToString) && m.Object?.Type == typeof(DateTime))
{
var arg = args.Count > 0 ? args[0] : null;
if (arg == null) statement = ToCast(quotedColName.ToString());
else statement = $"strftime('{arg}',{quotedColName})";
return new PartialSqlString(statement);
}
if (m.Method.Name == nameof(string.Substring))
{
var startIndex = int.Parse(args[0].ToString()) + 1;
if (args.Count == 2)
{
var length = int.Parse(args[1].ToString());
statement = $"substr({quotedColName}, {startIndex}, {length})";
}
else
statement = $"substr({quotedColName}, {startIndex})";
return new PartialSqlString(statement);
}
return base.VisitColumnAccessMethod(m);
}
protected override object VisitSqlMethodCall(MethodCallExpression m)
{
var args = this.VisitInSqlExpressionList(m.Arguments);
object quotedColName = args[0];
args.RemoveAt(0);
var statement = "";
switch (m.Method.Name)
{
case "In":
statement = ConvertInExpressionToSql(m, quotedColName);
break;
case "Desc":
statement = $"{quotedColName} DESC";
break;
case "As":
statement =
$"{quotedColName} AS {base.DialectProvider.GetQuotedColumnName(RemoveQuoteFromAlias(args[0].ToString()))}";
break;
case "Sum":
case "Count":
case "Min":
case "Max":
case "Avg":
statement = string.Format("{0}({1}{2})",
m.Method.Name,
quotedColName,
args.Count == 1 ? $",{args[0]}" : "");
break;
case "CountDistinct":
statement = $"COUNT(DISTINCT {quotedColName})";
break;
default:
return base.VisitSqlMethodCall(m);
}
return new PartialSqlString(statement);
}
protected override PartialSqlString ToLengthPartialString(object arg)
{
return new PartialSqlString($"LENGTH({arg})");
}
}
}