// 获取 String 类型的 SQL 片断
protected override string GetSqlValueByString(object value, object dbType, int?size = null)
{
bool unicode = DbTypeUtils.IsUnicode(dbType);
string result = this.EscapeQuote(value.ToString(), unicode, true);
return(result);
}
/// <summary>
/// 访问 IsNullOrEmpty 方法
/// </summary>
/// <param name="m">方法表达式</param>
protected override Expression VisitIsNullOrEmpty(MethodCallExpression m)
{
_builder.Append("ISNULL(");
_visitor.Visit(m.Arguments[0]);
_builder.Append(",");
bool isUnicode = DbTypeUtils.IsUnicode(_visitedMark.Current);
string empty = isUnicode ? "N''" : "''";
_builder.Append(empty);
_builder.Append(") = ");
_builder.Append(empty);
return(m);
}
/// <summary>
/// 访问 string.Contains 方法
/// </summary>
/// <param name="m">方法表达式</param>
protected override Expression VisitStringContains(MethodCallExpression m)
{
// https://www.cnblogs.com/yangmingyu/p/6928209.html
// 对于其他的特殊字符：'^'， '-'， ']' 因为它们本身在包含在 '[]' 中使用，所以需要用另外的方式来转义，于是就引入了 like 中的 escape 子句，另外值得注意的是：escape 可以转义所有的特殊字符。
// EF 的 Like 不用参数化...
_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 = DbTypeUtils.IsUnicode(_visitedMark.Current, out column);
string value = _dbValue.GetSqlValue(m.Arguments[0].Evaluate().Value, _builder.Token, column);
if (!_builder.Parameterized && value != null)
{
value = value.TrimStart('N').Trim('\'');
}
if (_builder.Parameterized)
{
_builder.Append("(");
_builder.Append("'%' + ");
_builder.Append(value);
_builder.Append(" + '%'");
_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>
/// 访问 EndWidth 方法
/// </summary>
/// <param name="m">方法表达式</param>
protected override Expression VisitEndsWith(MethodCallExpression m)
{
if (m != null)
{
_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 = DbTypeUtils.IsUnicode(_visitedMark.Current, out column);
string value = _dbValue.GetSqlValue(m.Arguments[0].Evaluate().Value, _builder.Token, 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(DbTypeUtils.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(DbTypeUtils.IsUnicode(m, out column));
}
/// <summary>
/// 判断指定类型是否是unicode
/// </summary>
protected override bool IsUnicode(object dbType)
{
return(DbTypeUtils.IsUnicode(dbType));
}
/// <summary>
/// 访问 ToString 方法
/// </summary>
/// <param name="node">即将访问的表达式</param>
protected override Expression VisitToStringImpl(Expression node)
{
// => a.ID.ToString()
// 字符串不进行转换
if (node == null || node.Type == typeof(string))
{
return(_visitor.Visit(node));
}
ColumnAttribute column = null;
bool isUnicode = DbTypeUtils.IsUnicode(_visitedMark.Current, out column);
bool isBytes = node.Type == typeof(byte[]);
bool isDate = node.Type == typeof(DateTime) ||
node.Type == typeof(DateTime?) ||
node.Type == typeof(TimeSpan) ||
node.Type == typeof(TimeSpan?) ||
node.Type == typeof(DateTimeOffset) ||
node.Type == typeof(DateTimeOffset?);
if (!isBytes)
{
if (isUnicode)
{
_builder.Append("TO_NCHAR(");
}
else
{
_builder.Append("TO_CHAR(");
}
}
// 其它类型转字符串
if (isDate)
{
_visitor.Visit(node);
string format = string.Empty;
ColumnAttribute c = _visitedMark.Current != null?TypeUtils.GetColumnAttribute(_visitedMark.Current.Member, _visitedMark.Current.ReflectedType) : null;
if (c != null && DbTypeUtils.IsDate(c.DbType))
{
format = "yyyy-mm-dd";
}
else if (c != null && (DbTypeUtils.IsDateTime(c.DbType) || DbTypeUtils.IsDateTime2(c.DbType)))
{
format = "yyyy-mm-dd hh24:mi:ss.ff";
}
else if (c != null && DbTypeUtils.IsDateTimeOffset(c.DbType))
{
format = "yyyy-mm-dd hh24:mi:ss.ff tzh:tzm";
}
// 没有显式指定数据类型，则根据表达式的类型来判断
if (string.IsNullOrEmpty(format))
{
if (node.Type == typeof(DateTime) || node.Type == typeof(DateTime?))
{
format = "yyyy-mm-dd hh24:mi:ss.ff";
}
else if (node.Type == typeof(DateTimeOffset) || node.Type == typeof(DateTimeOffset?))
{
format = "yyyy-mm-dd hh24:mi:ss.ff tzh:tzm";
}
}
if (!string.IsNullOrEmpty(format))
{
_builder.Append(",'");
_builder.Append(format);
_builder.Append("'");
}
}
else if (isBytes)
{
_builder.Append("RTRIM(DBMS_LOB.SUBSTR(");
_visitor.Visit(node);
_builder.Append(')');
}
else if (node.Type == typeof(Guid))
{
_builder.Append("REGEXP_REPLACE(REGEXP_REPLACE(");
_visitor.Visit(node);
_builder.Append(@",'(.{8})(.{4})(.{4})(.{4})(.{12})', '\1-\2-\3-\4-\5'),'(.{2})(.{2})(.{2})(.{2}).(.{2})(.{2}).(.{2})(.{2})(.{18})','\4\3\2\1-\6\5-\8\7\9')");
}
else
{
_visitor.Visit(node);
}
_builder.Append(')');
return(node);
}
/// <summary>
/// 访问 ToString 方法
/// </summary>
protected override Expression VisitToStringImpl(Expression node)
{
// => a.ID.ToString()
// 字符串不进行转换
if (node == null || node.Type == typeof(string))
{
return(_visitor.Visit(node));
}
ColumnAttribute column = null;
bool isUnicode = DbTypeUtils.IsUnicode(_visitedMark.Current, out column);
string native = isUnicode ? "NVARCHAR" : "VARCHAR";
// 其它类型转字符串
bool isDate = node.Type == typeof(DateTime) ||
node.Type == typeof(DateTime?) ||
node.Type == typeof(TimeSpan) ||
node.Type == typeof(TimeSpan?) ||
node.Type == typeof(DateTimeOffset) ||
node.Type == typeof(DateTimeOffset?);
if (isDate)
{
native = string.Format("{0}(64)", native);
_builder.Append("CONVERT(");
_builder.Append(native);
_builder.Append(",");
_visitor.Visit(node);
_builder.Append(",121)");
}
else if (node.Type == typeof(byte[]))
{
native = string.Format("{0}(max)", native);
_builder.Append("CONVERT(");
_builder.Append(native);
_builder.Append(",");
_visitor.Visit(node);
_builder.Append(",1)");
}
else if (node.Type == typeof(Guid))
{
native = string.Format("{0}(64)", native);
_builder.Append("CAST(");
_visitor.Visit(node);
_builder.Append(" AS ");
_builder.Append(native);
_builder.Append(')');
}
else
{
if (column != null && column.Size > 0)
{
native = string.Format("{0}({1})", native, column.Size);
}
else if (column != null && column.Size == -1)
{
native = string.Format("{0}(max)", native);
}
else
{
native = string.Format("{0}(max)", native);
}
_builder.Append("CAST(");
_visitor.Visit(node);
_builder.Append(" AS ");
_builder.Append(native);
_builder.Append(')');
}
return(node);
}
