/// <summary>
/// 解析表达式代码。
/// </summary>
/// <param name="expression">表达式。</param>
/// <param name="getAliasFunc">获取别名方法。</param>
/// <returns>返回解析后的SQL字符串。</returns>
protected string Visit(Expression expression, Func <Type, string> getAliasFunc)
{
var visitor = _visitorFactory.Create(getAliasFunc);
visitor.Visit(expression);
return(visitor.ToString());
}
/// <summary>
/// 生成更新语句。
/// </summary>
/// <param name="table">表格。</param>
/// <param name="instance">当前实例。</param>
/// <param name="where">条件表达式。</param>
/// <returns>返回生成的SQL语句。</returns>
protected override string GenerateSqlUpdate(ITable table, object instance, Expression @where)
{
var builder = new IndentedStringBuilder();
builder.Append("UPDATE ").Append(table).Append(" SET ");
var items = new List <string>();
ForEachProperty(instance, (k, v) =>
{
items.Add($"{SqlHelper.DelimitIdentifier(k)}={SqlHelper.EscapeLiteral(v)}");
});
builder.JoinAppend(items);
var visitor = _visitorFactory.Create();
visitor.Visit(where);
builder.AppendEx(visitor.ToString(), " WHERE {0}");
return(builder.ToString());
}
/// <summary>
/// 解析表达式。
/// </summary>
/// <param name="expression">表达式实例。</param>
/// <returns>返回解析的表达式字符串。</returns>
public virtual string Visit(Expression expression)
{
if (expression == null)
{
return(null);
}
var visitor = _visitorFactory.Create();
visitor.Visit(expression);
return(visitor.ToString());
}
/// <summary>
/// 生成更新语句。
/// </summary>
/// <param name="entityType">当前实体。</param>
/// <param name="instance">当前实例。</param>
/// <param name="where">条件表达式。</param>
/// <returns>返回生成的SQL语句。</returns>
protected override string GenerateSqlUpdate(IEntityType entityType, object instance, Expression @where)
{
var builder = new IndentedStringBuilder();
builder.Append("UPDATE ").Append(entityType.Table).Append(" SET ");
var items = new List <string>();
ForEachProperty(instance, (k, v) =>
{
if (k.IsDefined(typeof(NotUpdatedAttribute), true))
{
return;
}
items.Add($"{SqlHelper.DelimitIdentifier(k.Name)}={SqlHelper.EscapeLiteral(v)}");
});
builder.JoinAppend(items);
var visitor = _visitorFactory.Create();
visitor.Visit(where);
builder.AppendEx(visitor.ToString(), " WHERE {0}");
return(builder.ToString());
}