/// <summary>
/// 获取 String 类型的 SQL 片断
/// </summary>
/// <param name="value">值</param>
/// <param name="dbType">数据类型</param>
/// <param name="size">长度</param>
/// <returns></returns>
protected override string GetSqlValueOfString(object value, object dbType, int?size = null)
{
bool unicode = SQLiteUtils.IsUnicode(dbType);
string result = this.EscapeQuote(value.ToString(), unicode, true);
return(result);
}
/// <summary>
/// 访问 Contains 方法
/// </summary>
/// <param name="m">方法表达式</param>
protected override Expression VisitStringContains(MethodCallExpression m)
{
_visitor.Visit(m.Object);
if (this.NotOperands != null && this.NotOperands.Contains(m))
{
_builder.Append(" NOT");
}
_builder.Append(" LIKE ");
if (m.Arguments[0].CanEvaluate())
{
ColumnAttribute column = null;
bool isUnicode = SQLiteUtils.IsUnicode(_visitedMark.Current, out column);
string value = _constor.GetSqlValue(m.Arguments[0].Evaluate().Value, _builder.TranslateContext, column);
if (!_builder.Parameterized && value != null)
{
value = value.TrimStart('N').Trim('\'');
}
if (_builder.Parameterized)
{
_builder.Append("'%' || ");
_builder.Append(value);
_builder.Append(" || '%'");
}
else
{
if (isUnicode)
{
_builder.Append('N');
}
_builder.Append("'%");
_builder.Append(value);
_builder.Append("%'");
}
}
else
{
_builder.Append("('%' || ");
_visitor.Visit(m.Arguments[0]);
_builder.Append(" || '%')");
}
return(m);
}
/// <summary>
/// 检查字段或属性成员声明的 DbType 是否为 Unicode 数据类型
/// </summary>
/// <param name="m">将要检查的字段或属性成员</param>
/// <param name="column">字段或属性成员显示声明的列特性</param>
/// <returns></returns>
public static bool IsUnicode(MemberVisitedStack.VisitedMember m, out ColumnAttribute column)
{
column = m != null?TypeUtils.GetColumnAttribute(m.Member, m.ReflectedType) : null;
return(SQLiteUtils.IsUnicode(column == null ? null : column.DbType));
}
/// <summary>
/// 检查字段或属性成员声明的 DbType 是否为 Unicode 数据类型
/// </summary>
/// <param name="m">将要检查的字段或属性成员</param>
/// <returns></returns>
public static bool IsUnicode(MemberVisitedStack.VisitedMember m)
{
ColumnAttribute column = null;
return(SQLiteUtils.IsUnicode(m, out column));
}