Data Shaping technology - Data configuration
"Configuration data" enables you to reply to the answer can be expressed by forming the Recordset question. The definition of configuration data columns forming Recordset from out that the relationship between entry and data-filling approach to the Recordset.
Forming out of the Recordset can contain from data providers (such as SQL Server) data, the reference to another Recordset, the Recordset to carry out a calculated value of the entire Recordset to operate out of the value received, or can be new fiction out of the air.
In search of another Recordset contains references to the value of the column, ADO will automatically return to that by quoting the actual Recordset. Recordset the Recordset contains another known as "hierarchical Recordset" or "cursor classification."
For example, suppose you want to be issued by the company each client a list of all orders. Customers can include name of the database table and Orders issued orders configuration data. The same as the above example, ADO will return to customer records Recordset. However, each additional will be out at the same time, the column contains references to all the client orders Recordset.
Improve the shape can be obtained by the state with a list of total sales. Customers table in the address column contains the state of each client, and the Orders table contains the number of out is the number of each order. Different configuration of the data command, then ADO will return Recordset, the Recordset contains a line for each state (in which each line contains the logo out of state), the state's total sales volume of all orders and set out the state's All customer references Recordset. access to the Recordset customers will find the same with the previous example, each customer line contains contains all of the orders of the client references Recordset.
Shape command syntax allows you to programmatically create a shape Recordset. Can then be programmed or appropriate visualization control components Recordset visit.
Overview of configuration data
ADO 2.0 introduced a function of configuration data, graded and Shape recordset command syntax.
ADO 2.1 introduced by the insertion command COMPUTE Reconstruction shape and parameters of the grandson of the total order.
Configuration data enables you to define columns forming Recordset from the list of entries that the relationship between the filling and data to the Recordset way.
Forming out of the Recordset can contain data, the reference to another Recordset, the Recordset to carry out a calculated value of the entire Recordset to operate out of the value received, or can be empty out the new fiction.
In search of another Recordset contains references to the value of the column, ADO will automatically return to that by quoting the actual Recordset. Recordset the Recordset contains another known as "hierarchical Recordset". Recordsets classification shows the father - son relationship, in which "Father" is contained in the Recordset, and "son" was included in Recordset. Reference to the Recordset is actually a subset pair (also known as "subset") reference. A single parent can contain multiple sub-Recordset.
ADO 2.0 has also introduced a new Shape command syntax can be programmed to create the Recordset object shape. Shape, like any other command to the command text issued ADO.
Shape the use of command syntax can be classified in two ways to create the Recordset object. One is the additional sub-Recordset to the parent Recordset, in general, the father and son must have at least one out: In the line of the father of the value and sub-out all the line out of the same value.
The second sub-Recordset is generated from the parent Recordset. Son in the cited in the parent Recordset, there must be a subset of column. Father of the creation of other ways out are: pair out of the total computing, computing the expression Recordset line, use the BY keyword specified sub-groups listed, or additional new air out.
Hierarchical Recordset objects can be nested to any depth (ie the creation of a sub-sub-Recordset object Recordset object, so to continue).
Procedures or through the corresponding visual controls, you have access to the Recordset the Recordset forming components.
Microsoft provides a command to generate Shape visualization tools (please refer to the subject of Visual Basic "Data Environment Designer") and another to show the cursor classification of visualization tools (see Visual Basic theme, "Using Microsoft Hierarchical Flexgrid Control ").
Reconstruction of shape
Shape order by clause to create the Recordset can be assigned to "alias" (the general use AS keyword). In ADO 2.1, the shape of the alias Recordset can be completely different in order to quote. In other words, may issue a new command to change the Shape (ie reconstruction of shape) configuration before the Recordset. To support this feature, ADO provides a new Recordset object's Name attribute.
Restrictions should not be listed as additional to an existing Recordset, or in any of COMPUTE clause to insert the parameters of the Recordset to the Recordset object reconstruction or shape, or configuration in addition to being anything other than the Recordset Total operating Recordset implementation.
Shape order by clause to create a subset list can be "a subset - the alias name" (General use AS keyword). Can be used for the logo contains a complete list of the sub-name, logo in the subset of any shape out Recordset. For example, if father and son set out chap1 contains amt has a number of sub-subset of chap2, then full name will be chap1.chap2.amt. Then, the full name can be used as a parameter in the aggregate function (SUM, AVG, MAX, MIN, COUNT, STDEV, or ANY) to use.
COMPUTE command used to insert the parameters of the command
Typical parameters of the shape through the APPEND command with the parent Recordset query command to create the clause, as well as an order parameter query (that is, a placeholder that contains the parameters: a question mark "?" Command) to create another sub-clause Recordset. Recordset forming finally have two, father and son to occupy the upper strata.
Recordset to create a sub-clause can now be nested any number of shapes COMPUTE command, the command in the most nested includes query parameters. By forming a multiple Recordset, to occupy the top of the parent, son to occupy the bottom, and COMPUTE command generated by the shape of any number of Recordsets layer is inserted to occupy.
The characteristics of typical usage is to call the function and shape of the total group COMPUTE command functions, to create a Recordset on the sub-analysis of information Recordset object to insert. In short, because this is the Shape parameter of the command, when the father out to be a subset of the visit, you can retrieve a subset of the new Recordset. Because the insert from the sub-layer, which will also be recalculated
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