/// <summary>
/// 创建 SQL 命令
/// </summary>
/// <param name="dbQueryable">查询 语句</param>
/// <param name="indent">缩进</param>
/// <param name="isOuter">是否最外层，内层查询不需要结束符(;)</param>
/// <param name="parameters">已存在的参数列表</param>
/// <returns></returns>
public DbCommandDefinition Resolve <T>(IDbQueryable <T> dbQueryable, int indent = 0, bool isOuter = true, List <IDbDataParameter> parameters = null)
{
// 设置该查询是否需要参数化
if (!((DbQueryable)dbQueryable).HasSetParameterized)
{
dbQueryable.Parameterized = true;
}
if (dbQueryable.Parameterized && parameters == null)
{
parameters = new List <IDbDataParameter>(8);
}
// 解析查询语义
IDbQueryableInfo <T> info = DbQueryParser.Parse(dbQueryable);
DbQueryableInfo_Select <T> sQuery = info as DbQueryableInfo_Select <T>;
if (sQuery != null)
{
return(this.ParseSelectCommand <T>(sQuery, indent, isOuter, dbQueryable.Parameterized ? parameters : null));
}
DbQueryableInfo_Insert <T> nQuery = info as DbQueryableInfo_Insert <T>;
if (nQuery != null)
{
return(this.ParseInsertCommand <T>(nQuery, dbQueryable.Parameterized ? parameters : null));
}
DbQueryableInfo_Update <T> uQuery = info as DbQueryableInfo_Update <T>;
if (uQuery != null)
{
return(this.ParseUpdateCommand <T>(uQuery, dbQueryable.Parameterized ? parameters : null));
}
DbQueryableInfo_Delete <T> dQuery = info as DbQueryableInfo_Delete <T>;
if (dQuery != null)
{
return(this.ParseDeleteCommand <T>(dQuery, dbQueryable.Parameterized ? parameters : null));
}
throw new NotImplementedException();
}
// 创建 INSRT 命令 protected abstract DbCommandDefinition ParseInsertCommand <T>(DbQueryableInfo_Insert <T> nQuery, List <IDbDataParameter> parameters = null);
// 解析查询语义
static IDbQueryableInfo <TElement> Parse <TElement>(IDbQueryable <TElement> dbQuery, int startIndex)
{
// 目的：将query 转换成增/删/改/查
// 1、from a in context.GetTable<T>() select a 此时query里面可能没有SELECT 表达式
// 2、Take 视为一个查询的结束位，如有更多查询，应使用嵌套查询
// 3、Uion 分页查询也使嵌套语义
Type type = null;
bool isDistinct = false;
bool isAny = false;
bool isSubQuery = false;
int? skip = null;
int? take = null;
int? outerIndex = null;
List <Expression> where = new List <Expression>(); // WHERE
List <Expression> having = new List <Expression>(); // HAVING
List <DbExpression> join = new List <DbExpression>(); // JOIN
List <DbExpression> orderBy = new List <DbExpression>(); // ORDER BY
List <DbExpression> include = new List <DbExpression>(); // ORDER BY
List <IDbQueryableInfo <TElement> > union = new List <IDbQueryableInfo <TElement> >();
Expression select = null; // SELECT #
DbExpression insert = null; // INSERT #
DbExpression update = null; // UPDATE #
DbExpression delete = null; // DELETE #
DbExpression groupBy = null; // GROUP BY #
DbExpression statis = null; // SUM/MAX #
for (int index = startIndex; index < dbQuery.DbExpressions.Count; ++index)
{
DbExpression curExp = dbQuery.DbExpressions[index];
// Take(n)
if (take != null || (skip != null && curExp.DbExpressionType != DbExpressionType.Take) || isDistinct || isSubQuery)
{
outerIndex = index;
break;
}
#region 分析语义
switch (curExp.DbExpressionType)
{
case DbExpressionType.None:
case DbExpressionType.All:
continue;
case DbExpressionType.Any:
isAny = true;
if (curExp.Expressions != null)
{
where.Add(curExp.Expressions[0]);
}
break;
case DbExpressionType.AsSubQuery:
isSubQuery = true;
//if (curExp.Expressions != null) where.Add(curExp.Expressions[0]);
break;
case DbExpressionType.Union:
var uQuery = (curExp.Expressions[0] as ConstantExpression).Value as IDbQueryable <TElement>;
var u = DbQueryParser.Parse(uQuery);
union.Add(u);
continue;
case DbExpressionType.Include:
include.Add(curExp);
continue;
case DbExpressionType.GroupBy:
groupBy = curExp;
continue;
case DbExpressionType.GetTable:
type = (curExp.Expressions[0] as ConstantExpression).Value as Type;
continue;
case DbExpressionType.Average:
case DbExpressionType.Min:
case DbExpressionType.Sum:
case DbExpressionType.Max:
statis = curExp;
continue;
case DbExpressionType.Count:
statis = curExp;
if (curExp.Expressions != null)
{
where.Add(curExp.Expressions[0]);
}
continue;
case DbExpressionType.Distinct:
isDistinct = true;
continue;
case DbExpressionType.First:
case DbExpressionType.FirstOrDefault:
take = 1;
if (curExp.Expressions != null)
{
where.Add(curExp.Expressions[0]);
}
continue;
case DbExpressionType.Join:
case DbExpressionType.GroupJoin:
case DbExpressionType.GroupRightJoin:
select = curExp.Expressions[3];
join.Add(curExp);
continue;
case DbExpressionType.OrderBy:
case DbExpressionType.OrderByDescending:
orderBy.Add(curExp);
continue;
case DbExpressionType.Select:
select = curExp.Expressions != null ? curExp.Expressions[0] : null;
continue;
case DbExpressionType.SelectMany:
select = curExp.Expressions[1];
if (CheckSelectMany(dbQuery.DbExpressions, curExp, startIndex))
{
join.Add(curExp);
}
continue;
case DbExpressionType.Single:
case DbExpressionType.SingleOrDefault:
take = 1;
if (curExp.Expressions != null)
{
where.Add(curExp.Expressions[0]);
}
continue;
case DbExpressionType.Skip:
skip = (int)(curExp.Expressions[0] as ConstantExpression).Value;
continue;
case DbExpressionType.Take:
take = (int)(curExp.Expressions[0] as ConstantExpression).Value;
continue;
case DbExpressionType.ThenBy:
case DbExpressionType.ThenByDescending:
orderBy.Add(curExp);
continue;
case DbExpressionType.Where:
var predicate = groupBy == null ? where : having;
if (curExp.Expressions != null)
{
predicate.Add(curExp.Expressions[0]);
}
continue;
case DbExpressionType.Insert:
insert = curExp;
continue;
case DbExpressionType.Update:
update = curExp;
continue;
case DbExpressionType.Delete:
delete = curExp;
continue;
default:
throw new NotSupportedException(string.Format("{0} is not support.", curExp.DbExpressionType));
}
#endregion
}
// 没有解析到INSERT/DELETE/UPDATE/SELECT表达式，并且没有相关统计函数，则默认选择FromType的所有字段
bool useFullColumns = insert == null && delete == null && update == null && select == null && statis == null;
if (useFullColumns)
{
select = Expression.Constant(type ?? typeof(TElement));
}
var sQuery = new DbQueryableInfo_Select <TElement>();
sQuery.FromType = type;
sQuery.HaveDistinct = isDistinct;
sQuery.HaveAny = isAny;
sQuery.Join = join;
sQuery.OrderBy = orderBy;
sQuery.GroupBy = groupBy;
sQuery.Statis = statis;
sQuery.Union = union;
sQuery.Include = include;
sQuery.Skip = skip != null ? skip.Value : 0;
sQuery.Take = take != null ? take.Value : 0;
sQuery.Select = new DbExpression(DbExpressionType.Select, select);
sQuery.Where = new DbExpression(DbExpressionType.Where, DbQueryParser.CombineWhere(where));
sQuery.Having = new DbExpression(DbExpressionType.None, DbQueryParser.CombineWhere(having));
sQuery.SourceQuery = dbQuery;
// 更新
if (update != null)
{
var uQuery = new DbQueryableInfo_Update <TElement>();
ConstantExpression expression2 = update.Expressions != null ? update.Expressions[0] as ConstantExpression : null;
if (expression2 != null)
{
uQuery.Entity = expression2.Value;
}
else
{
uQuery.Expression = update.Expressions[0];
}
uQuery.SelectInfo = sQuery;
uQuery.SourceQuery = dbQuery;
return(uQuery);
}
// 删除
if (delete != null)
{
var dQuery = new DbQueryableInfo_Delete <TElement>();
ConstantExpression expression2 = delete.Expressions != null ? delete.Expressions[0] as ConstantExpression : null;
if (expression2 != null)
{
dQuery.Entity = expression2.Value;
}
dQuery.SelectInfo = sQuery;
dQuery.SourceQuery = dbQuery;
return(dQuery);
}
// 新增
if (insert != null)
{
var nQuery = new DbQueryableInfo_Insert <TElement>();
if (insert.Expressions != null)
{
nQuery.Entity = (insert.Expressions[0] as ConstantExpression).Value;
if (insert.Expressions.Length > 1)
{
nQuery.EntityColumns = (insert.Expressions[1] as ConstantExpression).Value as IList <Expression>;
}
}
nQuery.SelectInfo = sQuery;
nQuery.Bulk = dbQuery.Bulk;
nQuery.SourceQuery = dbQuery;
dbQuery.DbQueryInfo = nQuery;
return(nQuery);
}
// 如果有一对多的导航关系，则产生嵌套语义的查询
if (select != null)
{
// 如果有uion但是没分页，应去掉orderby子句
if (sQuery.Union.Count > 0 && !(sQuery.Take > 0 || sQuery.Skip > 0))
{
sQuery.OrderBy = new List <DbExpression>();
}
// 检查嵌套查询语义
sQuery = DbQueryParser.TryBuilOuter(sQuery);
sQuery.SourceQuery = dbQuery;
}
// 解析嵌套查询
if (outerIndex != null)
{
var outQuery = DbQueryParser.Parse <TElement>(dbQuery, outerIndex.Value);
var nQuery = outQuery as DbQueryableInfo_Insert <TElement>;
var uQuery = outQuery as DbQueryableInfo_Update <TElement>;
if (nQuery != null)
{
if (nQuery.SelectInfo != null)
{
nQuery.SelectInfo.SubQueryInfo = sQuery;
}
else
{
nQuery.SelectInfo = sQuery;
}
nQuery.SourceQuery = dbQuery;
return(nQuery);
}
else if (uQuery != null)
{
if (uQuery.SelectInfo != null)
{
uQuery.SelectInfo.SubQueryInfo = sQuery;
}
else
{
uQuery.SelectInfo = sQuery;
}
uQuery.SourceQuery = dbQuery;
return(uQuery);
}
else
{
outQuery.SubQueryInfo = sQuery;
outQuery.SourceQuery = dbQuery;
return(outQuery);
}
}
// 查询表达式
return(sQuery);
}