9.6 Parameter Object

A Parameter object represents a parameter or argument associated with a Command object based on a parameterized query or stored procedure.
Collections
Properties
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All the Property objects for a specific instance of a Parameter object. This collection is not currently supported on UNIX.
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Methods
AppendChunk
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Appends data to a large text or binary data parameter.
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Properties
Attributes
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One or more characteristics of a parameter. This property is currently read-only on UNIX.
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Direction
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Indicates if the parameter is an input parameter, an output parameter, or both; or if the parameter is the output of a stored procedure.
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Name
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The name of the parameter.
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NumericScale
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The scale of numeric values in the parameter.
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Precision
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The degree of precision for numeric values in the parameter.
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Size
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The maximum size, in bytes or characters, of a parameter.
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Type
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The data type of the parameter.
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Value
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The value assigned to the parameter.
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Remarks
The Properties collection is not currently supported on UNIX.
Many providers support parameterized commands. These are commands where the desired action is defined once, but variables (or parameters) are used to alter some details of the command. For example, an SQL SELECT statement could use a parameter to define the matching criteria of a WHERE clause, and another to define the column name for a SORT BY clause.
The Parameter objects represent parameters associated with parameterized queries, or the in/out arguments and the return values of stored procedures. Depending on the functionality of the provider, some collections, methods, or properties of a Parameter object may not be available.
The collections, methods, and properties of a Parameter object are used to:
If you know the names and properties of the parameters associated with the stored procedure or parameterized query you wish to call, you can use the CreateParameter method to create Parameter objects with the appropriate property settings and use the Append method to add them to the Parameters collection. This lets you set and return parameter values without having to call the Refresh method on the Parameters collection to retrieve the parameter information from the provider, a potentially resource-intensive operation.
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