src/SqlMapper.psm1
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using namespace System.Collections.Concurrent using namespace System.Collections.Generic using namespace System.Data using namespace System.Diagnostics.CodeAnalysis using namespace System.Runtime.CompilerServices using module ./DbColumnInfo.psm1 using module ./DbTableInfo.psm1 <# .SYNOPSIS Maps data records to entity objects. #> class SqlMapper { <# .SYNOPSIS The singleton instance of the data mapper. #> static [SqlMapper] $Instance = [SqlMapper]::new() <# .SYNOPSIS The mapping between the entity types and their associated database tables. #> hidden static [ConcurrentDictionary[Type, DbTableInfo]] $Mapping = [ConcurrentDictionary[Type, DbTableInfo]]::new() <# .SYNOPSIS Creates a new data mapper. #> hidden SqlMapper() {} <# .SYNOPSIS Creates a new dyamic object from the specified data record. .PARAMETER Record A data record providing the properties to be set on the created object. .OUTPUTS The newly created object. #> [psobject] CreateInstance([IDataRecord] $Record) { return $this.CreateInstance([psobject], $Record) } <# .SYNOPSIS Creates a new object of the given type from the specified data record. .PARAMETER Type The object type. .PARAMETER Record A data record providing the properties to be set on the created object. .OUTPUTS The newly created object. #> [object] CreateInstance([Type] $Type, [IDataRecord] $Record) { return $this.CreateInstance($Type, [SqlMapper]::SplitOn($Record, @())[0]) } <# .SYNOPSIS Creates a new object tuple of the given types from the specified data record. .PARAMETER Types The object types. .PARAMETER Record A data record providing the properties to be set on the created objects. .PARAMETER SplitOn The fields from which to split and read the next objects. .OUTPUTS The newly created object tuple. #> [SuppressMessage("PSUseDeclaredVarsMoreThanAssignments", "discard")] [ITuple] CreateInstance([Type[]] $Types, [IDataRecord] $Record, [string[]] $SplitOn) { if (($Types.Count -lt 2) -or ($Types.Count -gt 7)) { throw [ArgumentException]::new("The number of object types is invalid.", "Types") } if ($SplitOn -and ($SplitOn.Count -ne $Types.Count - 1)) { throw [ArgumentException]::new("The number of split fields is invalid.", "SplitOn") } if (-not $SplitOn) { $SplitOn = (1..($Types.Count - 1)).ForEach{ "Id" } } $records = [SqlMapper]::SplitOn($Record, $SplitOn) $objects = [List[object]]::new($records.Count) for ($index = 0; $index -lt $Types.Count; $index++) { $object = ($records.Count -le $index) -or [SqlMapper]::IsNullObject($records[$index]) ? $null : $this.CreateInstance($Types[$index], $records[$index]) $objects.Add($object) } return $discard = switch ($objects.Count) { 2 { [ValueTuple]::Create[object, object]($objects[0], $objects[1]) } 3 { [ValueTuple]::Create[object, object, object]($objects[0], $objects[1], $objects[2]) } 4 { [ValueTuple]::Create[object, object, object, object]($objects[0], $objects[1], $objects[2], $objects[3]) } 5 { [ValueTuple]::Create[object, object, object, object, object]($objects[0], $objects[1], $objects[2], $objects[3], $objects[4]) } 6 { [ValueTuple]::Create[object, object, object, object, object, object]($objects[0], $objects[1], $objects[2], $objects[3], $objects[4], $objects[5]) } default { [ValueTuple]::Create[object, object, object, object, object, object, object]($objects[0], $objects[1], $objects[2], $objects[3], $objects[4], $objects[5], $objects[6]) } } } <# .SYNOPSIS Creates a new dynamic object from the specified hash table. .PARAMETER Properties A hash table providing the properties to be set on the created object. .OUTPUTS The newly created object. #> [psobject] CreateInstance([hashtable] $Properties) { return $this.CreateInstance([psobject], $Properties) } <# .SYNOPSIS Creates a new object of a given type from the specified hash table. .PARAMETER Type The object type. .PARAMETER Properties A hash table providing the properties to be set on the created object. .OUTPUTS The newly created object. #> [object] CreateInstance([Type] $Type, [hashtable] $Properties) { if ($Type -eq [psobject]) { return [pscustomobject] $Properties } $object = [Activator]::CreateInstance($Type) $table = $this.GetTable($Type) foreach ($name in $Properties.Keys.Where{ $table.Columns.ContainsKey($_) }) { $column = $table.Columns[$name] if ($column.CanWrite) { $column.SetValue($object, [SqlMapper]::ChangeType($Properties[$name], $column)) } } return $object } <# .SYNOPSIS Gets the table information associated with the specified type. .PARAMETER Type The type to inspect. .OUTPUTS The table information associated with the specified type. #> [DbTableInfo] GetTable([Type] $Type) { return [SqlMapper]::Mapping.GetOrAdd($Type, { param ($entityType) [DbTableInfo]::new($entityType) }) } <# .SYNOPSIS Converts the specified object into an equivalent value of the specified type. .PARAMETER Value The object to convert. .PARAMETER Column The column providing the type of object to return. .OUTPUTS The value of the given type corresponding to the specified object. #> hidden static [object] ChangeType([object] $Value, [DbColumnInfo] $Column) { return [SqlMapper]::ChangeType($Value, $Column.PropertyType, $Column.IsNullable) } <# .SYNOPSIS Converts the specified object into an equivalent value of the specified type. .PARAMETER Value The object to convert. .PARAMETER ConversionType The type of object to return. .OUTPUTS The value of the given type corresponding to the specified object. #> hidden static [object] ChangeType([object] $Value, [Type] $ConversionType) { return [SqlMapper]::ChangeType($Value, $ConversionType, $false) } <# .SYNOPSIS Converts the specified object into an equivalent value of the specified type. .PARAMETER Value The object to convert. .PARAMETER ConversionType The type of object to return. .PARAMETER IsNullable Value indicating whether the specified conversion type is nullable. .OUTPUTS The value of the given type corresponding to the specified object. #> [SuppressMessage("PSUseDeclaredVarsMoreThanAssignments", "discard")] hidden static [object] ChangeType([object] $Value, [Type] $ConversionType, [bool] $IsNullable) { $nullableType = [Nullable]::GetUnderlyingType($ConversionType) $targetType = $nullableType ?? $ConversionType if ($null -ne $Value) { $culture = [cultureinfo]::InvariantCulture return $discard = switch ($true) { { $targetType.IsEnum -and ($Value -is [string]) } { [Enum]::Parse($targetType, $Value, $true); break } { $targetType.IsEnum } { [Enum]::ToObject($targetType, [Convert]::ChangeType($Value, [Enum]::GetUnderlyingType($targetType), $culture)); break } default { $targetType.IsInstanceOfType($Value) ? $Value : [Convert]::ChangeType($Value, $targetType, $culture) } } } return $discard = switch ($true) { { $null -ne $nullableType } { $null; break } { $targetType.IsValueType } { [RuntimeHelpers]::GetUninitializedObject($targetType); break } { $targetType -eq [string] } { $IsNullable ? $null : ""; break } default { $IsNullable ? $null : [Activator]::CreateInstance($targetType) } } } <# .SYNOPSIS Returns a value indicating whether all values of the specified hash table are `$null`. .PARAMETER HashTable The hash table to inspect. .OUTPUTS `$true` if all values of the specified hash table are `$null`, otherwise `$false`. #> hidden static [bool] IsNullObject([hashtable] $HashTable) { return $HashTable.Values.Where{ $null -eq $_ }.Count -eq $HashTable.Count } <# .SYNOPSIS Splits the specified data record according to the specified fields. .PARAMETER Record The data record to split. .PARAMETER Fields The fields from which to split and read the next objects. .OUTPUTS An array of hash tables representing the objects extracted from the data record. #> hidden static [hashtable[]] SplitOn([IDataRecord] $Record, [string[]] $Fields) { $properties = [List[KeyValuePair[string, object]]]::new($Record.FieldCount) for ($index = 0; $index -lt $Record.FieldCount; $index++) { $value = $Record[$index] $properties.Add([KeyValuePair[string, object]]::new($Record.GetName($index), $value -is [DBNull] ? $null : $value)) } return [SqlMapper]::SplitOn($properties, $Fields) } <# .SYNOPSIS Splits the specified data record according to the specified fields. .PARAMETER Record The data record to split. .PARAMETER Fields The fields from which to split and read the next objects. .OUTPUTS An array of hash tables representing the objects extracted from the data record. #> hidden static [hashtable[]] SplitOn([KeyValuePair[string, object][]] $Record, [string[]] $Fields) { $properties = @{} if (-not $Fields) { foreach ($entry in $Record) { if (-not $properties.ContainsKey($entry.Key)) { $properties[$entry.Key] = $entry.Value } } return @($properties) } $field = "" $fieldQueue = [Queue[string]]::new($Fields) $records = [List[hashtable]]::new($Fields.Count + 1) $splitOn = $fieldQueue.Dequeue() for ($index = 0; $index -lt $Record.Count; $index++) { $entry = $Record[$index] if (($index -gt 0) -and ($entry.Key -eq $splitOn)) { $records.Add($properties) $properties = @{} if ($fieldQueue.TryDequeue([ref] $field)) { $splitOn = $field } } if (-not $properties.ContainsKey($entry.Key)) { $properties[$entry.Key] = $entry.Value } } $records.Add($properties) return $records.ToArray() } } |