Data Manipulation Languages
A DBMS must also provide a language designed to manipulate the data in a database. This language is called a database manipulation language, or DML. To the database programmer, however, the distinction between a DDL and a DML may be just a logical one, defined more by the purpose of the language than the syntax.
The Jet Data Manipulation Language
Example 7.2 is Jet DML code to add two records to the BOOKS table, set the index, and display the records.
Example 7-2. Jet DML Code Altering the BOOKS Table
' Data Manipulation Language example Dim rsBooks As Recordset ' Open the database Set dbLibrary = ws.OpenDatabase
("d:\dao\library.mdb") ' Create a recordset for the BOOKS table Set rsBooks = dbLibrary.OpenRecordset
("BOOKS") ' Add two records rsBooks.AddNew
rsBooks!ISBN = "0-99-345678-0" rsBooks!Title = "DB Programming is Fun" rsBooks.Update
rsBooks.AddNew
rsBooks!ISBN = "0-78-654321-0" rsBooks!Title = "DB Programming isn't Fun" rsBooks.Update
' Set index rsBooks.Index
= "ISBNIdx" ' Show the records rsBooks.MoveFirst
MsgBox "ISBN: " & rsBooks!ISBN & " TI: " & rsBooks!Title rsBooks.MoveNext
MsgBox "ISBN: " & rsBooks!ISBN & " TI: " & rsBooks!Title
As you can see even from this small example, the DML is designed to perform a variety of actions, such as:
Moving through the data in the database
Adding data to the database
Editing or updating data in the database
Deleting data from the database
Querying the data and returning those portions of the data that satisfy ...
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