編輯

共用方式為

Shape Append clause

  • 發行項

Applies to: Access 2013, Office 2013

The shape command APPEND clause appends a column or columns to a Recordset. Often these columns are chapter columns, which refer to a child Recordset.

Syntax

 
SHAPE [parent-command [[AS] parent-alias]] APPEND column-list

Description

The parts of this clause are as follows:

  • parent-command

  • Zero or one of the following (you may omit the parent-command entirely):

    • A provider command within curly braces ("{}") that returns a Recordset object. The command is issued to the underlying data provider, and its syntax depends on the requirements of that provider. This will typically be the SQL language, although ADO does not require any particular query language.

    • Another shape command embedded in parentheses.

    • The TABLE keyword, followed by the name of a table in the data provider.

  • parent-alias

    • An optional alias that refers to the parent Recordset.

  • column-list

    • One or more of the following:

      • An aggregate column.

      • A calculated column.

      • A new column created with the NEW clause.

      • A chapter column. A chapter column definition is enclosed in parentheses ("()"). See syntax below:

        
SHAPE [parent-command [[AS] parent-alias]] 
APPEND (child-recordset [ [[AS] child-alias] 
RELATE parent-column TO child-column | PARAMETER param-number, ... ]) 
[[AS] chapter-alias] 
[, ... ]

  • child-recordset

    • A provider command within curly braces ("{}") that returns a Recordset object. The command is issued to the underlying data provider, and its syntax depends on the requirements of that provider. This will typically be the SQL language, although ADO does not require any particular query language.

    • Another shape command embedded in parentheses.

    • The name of an existing shaped Recordset.

    • The TABLE keyword, followed by the name of a table in the data provider.

  • child-alias

    • An alias that refers to the child Recordset.

  • parent-column

    • A column in the Recordset returned by the parent-command.

  • child-column

    • A column in the Recordset returned by the child-command.

  • param-number

  • chapter-alias

    • An alias that refers to the chapter column appended to the parent.

Note

  • The "parent-column TO child-column" clause is actually a list, where each relation defined is separated by a comma.
  • The clause after the APPEND keyword is actually a list, where each clause is separated by a comma and defines another column to be appended to the parent.

Remarks

When you construct provider commands from user input as part of a SHAPE command, SHAPE will treat the user-supplied a provider command as an opaque string and pass them faithfully to the provider. For example, in the following SHAPE command,

 
SHAPE {select * from t1} APPEND ({select * from t2} RELATE k1 TO k2)

SHAPE will execute two commands: select * from t1 and (select * from t2 RELATE k1 TO k2). If the user supplies a compound command consisting of multiple provider commands separated by semicolons, SHAPE is not able to discern the difference. So in the following SHAPE command,

 
SHAPE {select * from t1; drop table t1} APPEND ({select * from t2} RELATE k1 TO k2)

SHAPE executes select * from t1; drop table t1 and (select * from t2 RELATE k1 TO k2), not realizing that drop table t1 is a separate and in this case, dangerous, provider command. Applications must always validate the user input to prevent such potential hacker attacks from happening.

This section includes the following topics: