/// <summary>
/// 创建 DELETE 命令
/// </summary>
/// <param name="tree">查询语义</param>
/// <param name="context">解析SQL命令上下文</param>
/// <returns></returns>
protected override DbRawCommand TranslateDeleteCommand <T>(DbQueryDeleteTree tree, ITranslateContext context)
{
ISqlBuilder builder = this.CreateSqlBuilder(context);
var typeRuntime = TypeRuntimeInfoCache.GetRuntimeInfo <T>();
builder.Append("DELETE FROM ");
builder.AppendTable(typeRuntime.TableSchema, typeRuntime.TableName, typeRuntime.IsTemporary);
builder.Append(" t0 ");
if (tree.Entity != null)
{
if (typeRuntime.KeyMembers == null || typeRuntime.KeyMembers.Count == 0)
{
throw new XFrameworkException("Delete<T>(T value) require entity must have key column.");
}
object entity = tree.Entity;
builder.AppendNewLine();
builder.Append("WHERE ");
foreach (FieldAccessorBase m in typeRuntime.KeyMembers)
{
var value = m.Invoke(entity);
var sqlExpression = this.Constor.GetSqlValue(value, context, m.Column);
builder.AppendMember("t0", m.Member, typeRuntime.Type);
builder.Append(" = ");
builder.Append(sqlExpression);
builder.Append(" AND ");
}
builder.Length -= 5;
}
else if (tree.Select != null)
{
AliasGenerator ag = this.PrepareTableAlias(tree.Select, context.AliasPrefix);
var cmd = new NpgDbSelectCommand(context, ag, DbExpressionType.Delete, tree.Select.SelectHasMany);
if (tree.Select.Joins != null)
{
var visitor = new NpgJoinExpressionVisitor(ag, cmd.JoinFragment, DbExpressionType.Delete, cmd);
visitor.Visit(tree.Select.Joins);
}
if (tree.Select.Wheres != null)
{
var visitor = new NpgWhereExpressionVisitor(ag, cmd.WhereFragment);
visitor.Visit(tree.Select.Wheres);
cmd.AddNavMembers(visitor.NavMembers);
}
builder.Append(cmd.CommandText);
}
builder.Append(';');
return(new DbRawCommand(builder.ToString(), builder.TranslateContext != null ? builder.TranslateContext.Parameters : null, System.Data.CommandType.Text));
}
/// <summary>
/// 创建 DELETE 命令
/// </summary>
/// <param name="tree">查询语义</param>
/// <param name="context">解析SQL命令上下文</param>
/// <returns></returns>
protected override DbRawCommand TranslateDeleteCommand <T>(DbQueryDeleteTree tree, ITranslateContext context)
{
ISqlBuilder builder = this.CreateSqlBuilder(context);
var typeRuntime = TypeRuntimeInfoCache.GetRuntimeInfo <T>();
builder.Append("DELETE FROM ");
builder.AppendTable(typeRuntime.TableSchema, typeRuntime.TableName, typeRuntime.IsTemporary);
builder.Append(" t0 ");
if (tree.Entity != null)
{
if (typeRuntime.KeyMembers == null || typeRuntime.KeyMembers.Count == 0)
{
throw new XFrameworkException("Delete<T>(T value) require entity must have key column.");
}
object entity = tree.Entity;
builder.AppendNewLine();
builder.Append("WHERE ");
foreach (FieldAccessorBase m in typeRuntime.KeyMembers)
{
var value = m.Invoke(entity);
var sqlExpression = this.Constor.GetSqlValue(value, context, m.Column);
builder.AppendMember("t0", m.Member, typeRuntime.Type);
builder.Append(" = ");
builder.Append(sqlExpression);
builder.Append(" AND ");
}
builder.Length -= 5;
}
else if (tree.Select != null)
{
// 解析查询用来确定是否需要嵌套
var cmd = this.TranslateSelectCommand(tree.Select, 0, false, this.CreateTranslateContext(context.DbContext)) as DbSelectCommand;
if ((cmd.NavMembers != null && cmd.NavMembers.Count > 0) || (tree.Select.Joins != null && tree.Select.Joins.Count > 0))
{
// 最外层仅选择 RowID 列
var outQuery = tree.Select;
outQuery.Select = new DbExpression(DbExpressionType.Select, Expression.Constant("t0.RowId", typeof(string)));
var iterator = outQuery;
while (iterator.Subquery != null)
{
var subquery = new OracleDbQuerySelectTree(iterator.Subquery);
iterator.Subquery = subquery;
iterator = subquery;
}
// 解析成 RowId IN 结构
cmd = (DbSelectCommand)this.TranslateSelectCommand(tree.Select, 1, false, context);
builder.Append("WHERE t0.RowId IN(");
builder.AppendNewLine(cmd.CommandText);
builder.Append(')');
}
else
{
AliasGenerator ag = this.PrepareTableAlias(tree.Select, context.AliasPrefix);
if (tree.Select.Joins != null)
{
var visitor = new JoinExpressionVisitor(ag, builder);
visitor.Visit(tree.Select.Joins);
}
if (tree.Select.Wheres != null)
{
var visitor = new WhereExpressionVisitor(ag, builder);
visitor.Visit(tree.Select.Wheres);
}
}
}
builder.Append(';');
return(new DbRawCommand(builder.ToString(), builder.TranslateContext != null ? builder.TranslateContext.Parameters : null, System.Data.CommandType.Text));
}
