Add a column to an Access Table
Now we have created our Table we can start adding columns
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| function New-AccessColumn {
[CmdletBinding()]
param (
[System.Data.OleDb.OleDbConnection]$connection,
[string]$table,
[switch]$notnull,
[parameter(ParameterSetName="datetime")]
[string]$dtname,
[parameter(ParameterSetName="unique")]
[string]$uniquename,
[parameter(ParameterSetName="binary")]
[string]$binname,
[parameter(ParameterSetName="bit")]
[string]$bitname,
[parameter(ParameterSetName="tinyinteger")]
[string]$tnyintname,
[parameter(ParameterSetName="smallinteger")]
[string]$smlintname,
[parameter(ParameterSetName="integer")]
[string]$intname,
[parameter(ParameterSetName="double")]
[string]$dblname,
[parameter(ParameterSetName="real")]
[string]$realname,
[parameter(ParameterSetName="float")]
[string]$floatname,
[parameter(ParameterSetName="decimal")]
[string]$decname,
[parameter(ParameterSetName="money")]
[string]$mnyname,
[parameter(ParameterSetName="char")]
[string]$charname,
[parameter(ParameterSetName="text")]
[string]$textname,
[parameter(ParameterSetName="image")]
[string]$imgname,
[parameter(ParameterSetName="char")]
[parameter(ParameterSetName="text")]
[int]$size = 10
)
switch ($psCmdlet.ParameterSetName){
datetime {$sql = "ALTER TABLE $table ADD COLUMN $dtname DATETIME" }
binary {$sql = "ALTER TABLE $table ADD COLUMN $binname BINARY" }
bit {$sql = "ALTER TABLE $table ADD COLUMN $bitname BIT" }
unique {$sql = "ALTER TABLE $table ADD COLUMN $uniquename UNIQUEIDENTIFIER" }
tinyinteger {$sql = "ALTER TABLE $table ADD COLUMN $tnyintname TINYINT" }
smallinteger {$sql = "ALTER TABLE $table ADD COLUMN $smlintname SMALLINT" }
integer {$sql = "ALTER TABLE $table ADD COLUMN $intname INTEGER" }
double {$sql = "ALTER TABLE $table ADD COLUMN $dblname DOUBLE" }
float {$sql = "ALTER TABLE $table ADD COLUMN $floatname FLOAT" }
real {$sql = "ALTER TABLE $table ADD COLUMN $realname REAL" }
decimal {$sql = "ALTER TABLE $table ADD COLUMN $decname DECIMAL" }
money {$sql = "ALTER TABLE $table ADD COLUMN $mnyname MONEY" }
char {$sql = "ALTER TABLE $table ADD COLUMN $charname CHARACTER($size)" }
text {$sql = "ALTER TABLE $table ADD COLUMN $textname TEXT($size)" }
image {$sql = "ALTER TABLE $table ADD COLUMN $imgname IMAGE" }
}
if ($notnull) {$sql = $sql + " NOT NULL"}
Write-Debug $sql
$cmd = New-Object System.Data.OleDb.OleDbCommand($sql, $connection)
$cmd.ExecuteNonQuery()
} |
The first set of parameters define the connection and table name. The $notnull parameter adds the NOT NULL statement to the SQL we create. This forces us to add a value for the column when we insert a row. These parameters are not part of a parameter set – this means they work with all parameter sets.
Parameter sets are used in this function to make the data types mutually exclusive – i.e. one call to Add-AccessColumn can add one column of one, and only one, data type. The size parameter applies to character and text data types so is a member of both parameter sets.
The parameter set is used in a switch statement to create the SQL to add a column of the correct type. If the $notnull switch is set we add the appropriate commands to the SQL.
With advanced functions in PowerShell v2 we get the ability to use the common parameters so I can use
New-AccessColumn -connection $db -table $table -dtname Mydate2 –notnull -Debug
and the Write-Debug statements will be triggered. In this case I get a dump of the SQL I have created. The function finishes by executing the SQL against the database as we have seen before.
As an example of using the function
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| Import-Module accessfunctions -Force
$db = Open-AccessDatabase -name test03.mdb -path c:\test
$table = "NewTable2"
New-AccessTable -table $table -connection $db
New-AccessColumn -connection $db -table $table -dtname Mydate
New-AccessColumn -connection $db -table $table -dtname Mydate2 -notnull
New-AccessColumn -connection $db -table $table -uniquename MyUnique
New-AccessColumn -connection $db -table $table -uniquename MyUnique2 -notnull
New-AccessColumn -connection $db -table $table -binname MyBinary
New-AccessColumn -connection $db -table $table -bitname MyBit
New-AccessColumn -connection $db -table $table -binname MyBinary2 -notnull
New-AccessColumn -connection $db -table $table -bitname MyBit2 -notnull
New-AccessColumn -connection $db -table $table -tnyintname MyTiny
New-AccessColumn -connection $db -table $table -smlintname MySmall
New-AccessColumn -connection $db -table $table -intname MyInt
New-AccessColumn -connection $db -table $table -tnyintname MyTiny2 -notnull
New-AccessColumn -connection $db -table $table -smlintname MySmall2 -notnull
New-AccessColumn -connection $db -table $table -intname MyInt2 -notnull
New-AccessColumn -connection $db -table $table -dblname MyDouble
New-AccessColumn -connection $db -table $table -realname MyReal
New-AccessColumn -connection $db -table $table -floatname MyFloat
New-AccessColumn -connection $db -table $table -decname MyDecimal
New-AccessColumn -connection $db -table $table -mnyname MyMoney
New-AccessColumn -connection $db -table $table -dblname MyDouble2 -notnull
New-AccessColumn -connection $db -table $table -realname MyReal2 -notnull
New-AccessColumn -connection $db -table $table -floatname MyFloat2 -notnull
New-AccessColumn -connection $db -table $table -decname MyDecimal2 -notnull
New-AccessColumn -connection $db -table $table -mnyname MyMoney2 -notnull
New-AccessColumn -connection $db -table $table -charname MyChar
New-AccessColumn -connection $db -table $table -charname MyChar2 -size 20
New-AccessColumn -connection $db -table $table -charname MyChar3 -size 20 -notnull
New-AccessColumn -connection $db -table $table -textname MyText
New-AccessColumn -connection $db -table $table -textname MyText2 -size 20
New-AccessColumn -connection $db -table $table -textname MyText3 -size 20 -notnull
New-AccessColumn -connection $db -table $table -imgname MyImg
New-AccessColumn -connection $db -table $table -imgname MyImg2 -notnull
Close-AccessDatabase $db |
Producing this becomes easy when using cut and paste within an editor.
Next we will look at removing columns and tables