Command

The command object is used to execute a single query against the database.
The query can perform actions like creating, adding, retrieving, deleting or updating records.
When data is retrieved it is returned as a Recordset object
Using the Command object also gives you the ability to pass parameters to your query.


Creating a Command


dbADOCommand = New ADODB.Command 


Note: You must use the command.execute method to substitute the parameters for the "?" placeholders


Command.Execute [ RecordsAffected ] [, Parameters ] [, Options]
RecordsAffected -
Parameters -
Options -


Command.CreateParameter [Name] [,Type][, Direction][, Size][, Value]
Name - Name of the parameter
Type - The datatype of the parameter. If you choose a variable length datatype you must provide a size in the size parameter. The default is adEmpty
Direction -
Size - Only necessary if the datatype is variable length
Value


Command.Parameters.Append [ ..............]


Connection Properties and Methods

NameTypeDescription
CommandTextPropertySets or returns a provider command
CommandTypePropertySets or returns the type of the command object
CancelMethodCancels an execution of a method
ActiveConnectionPropertySets or returns the definition for a connection
CommandTimeOutPropertySets or returns the number of seconds to wait while attempting to execute the command
PreparedPropertySets or returns
ExecuteMethodExecutes the query, SQL statement or procedure in the CommandText property
CreateParameterMethodCreates a new Parameter object. This is not automatically added to the parameters collection and must be done seperately using the Parameters.Append property
NamePropertySets or returns the name of the command object
StatePropertyReturns a value indicating if the command is open, closed, connecting, executing or retrieving

Note: If you specify a adDecimal or adNumeric datatype you will also have to set the NumericScale and Precision properties of the Parameter object


Command TypeadCmdUnknown (8)
 adCmdText (1) - source is an SQL statement
 adCmdTable (default) (2) - source is a table name (analgous to a DAO dynaset record)
 adCmdTableDirect (512) - source is a table name (analygous to a DAO dbpentable recordset
 adCmdStoredProc (4) - source is a stored procedure or function (analgous to a DAO dynaset on a sorted query)
 adCmdFile (256) - source is a name of a file that has persisted
 adExecuteNoRecords - source is a command or stored procedure that does not return rows
??adSyncConnect
 adSyncExecute
 adSyncFetch
 adSyncFetchNonBlocking


Example - Executing a SQL Statement

When returning a single value from a SQL statement use the To_Char() function to ensure that you return a string

Public dbADOConnect as ADODB.Connection 
Public dbADOCommand as ADODB.Command
Public dbADORecordset as ADODB.Recordset
Public sSQLQuery as String
Public sConnectionStr as String

sConnectionStr = "------------------------"

Set dbADOConnect = New ADODB.Connection
dbADOConnect.Open sConnectionStr, sUserID, sPassword, adConnectUnspecified
dbADOConnect.CursorLocation = ADODB.adUseClient

Set dbADOCommand = New ADODB.Command

sSQLQuery = "-------------------------"

dbADOCommand.CommandText = sSQLQuery
dbADOCommand.CommandType = ADODB.dbCmdText

Set dbADORecordSet = New ADODB.Recordset
Set dbADORecordSet = dbADOCommand.Execute

Set dbADOCommand = Nothing
Set dbADORecordset = Nothing
Set dbADOConnect = Nothing


Example - A Dynamic Cursor batching any changes to the Recordset)

dbADORecordSet = New ADODB.Recordset 
dbADORecordSet.Open dbADOCommand, _
                      dbADOConnection, _
                      adOpenDymanic, _
                      adLockBatchOptimistic



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