ADO.NET Object Model

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Figure B.2. The ADO.NET Document Object Model.

ADO.NET DbTypes

Table B.1. SqlDbType Compared to OleDbType

SqlDbType	OleDbType	Description
BigInt	BigInt	Int64 ” A 64-bit signed integer.
Binary	Binary	Array of type Byte ” A fixed-length stream of binary data ranging between 1 and 8,000 bytes.
Bit	-	Boolean ” An unsigned numeric value that can be 0, 1, or a null reference (Nothing in Visual Basic).
-	Boolean	Boolean ” A boolean value ( DBTYPE_BOOL ).
-	BSTR	String ” A null- terminated character string of Unicode characters ( DBTYPE_BSTR ).
Char	Char	String ” A fixed-length stream of non-Unicode characters ranging between 1 and 8,000 characters.
DateTime	Date	DateTime ” Date and time data ranging in value from January 1, 1753 to December 31, 9999 to an accuracy of 3.33 milliseconds .
-	DBDate	DateTime ” Date data in the format yyyymmdd ( DBTYPE_DBDATE ).
	DBTime	TimeSpan ” Time data in the format hhmmss ( DBTYPE_DBTIME ).
Decimal	Decimal	Decimal ” A fixed precision and scale numeric value between “10E38 “1 and 10E38 “1.
-	Empty	Empty ” No value ( DBTYPE_EMPTY ).
-	Error	Exception ” A 32-bit error code ( DBTYPE_ERROR ).
-	Filetime	DateTime ” A 64-bit unsigned integer representing the number of 100- nanosecond intervals since January 1, 1601 ( DBTYPE_FILETIME ).
Float	Double	Double ” A floating point number within the range of “1.79E +308 through 1.79E +308.
Image	-	Array of type Byte ” A variable-length stream of binary data ranging from 0 to 2E31 “1(or 2,147,483,647) bytes.
Int	Integer	Int32 ” A 32-bit signed integer.
-	LongVarBinary	Array of type Byte ” A long binary value ( OleDbParameter only).
-	LongVarWChar	String ” A long string value ( OleDbParameter only).
-	Numeric	Decimal ” An exact numeric value with a fixed precision and scale ( DBTYPE_NUMERIC ).
Money	Currency	Decimal ” Currency value ranging from “2E63 (or “922,337,203,685,477.5808) to 2E63 “1(or +922,337,203,685,477.5807) with an accuracy to a ten-thousandth of a currency unit.
NChar	-	String ” A fixed-length stream of Unicode characters ranging between 1 and 4,000 characters.
NText	-	String ” A variable-length stream of Unicode data with a maximum length of 2E30 “1 (or 1,073,741,823) characters.
NVarChar	-	String ” A variable-length stream of Unicode characters ranging between 1 and 4,000 characters. Note: Implicit conversion fails if the string is greater than 4,000 characters. Explicitly set the object when working with strings longer than 4,000 characters.
-	PropVariant	Object ” An automation PROPVARIANT ( DBTYPE_PROP_VARIANT ).
Real	Single	Single ” A floating point number within the range of “3.40E +38 through 3.40E +38.
SmallDateTime	-	DateTime ” Date and time data ranging in value from January 1, 1900 to June 6, 2079 to an accuracy of one minute.
SmallInt	SmallInt	Int16 ” A 16-bit signed integer.
SmallMoney	-	Decimal ” A currency value ranging from “214,748.3648 to +214,748.3647 with an accuracy to a ten-thousandth of a currency unit.
Text	LongVarChar	String ” A variable-length stream of non-Unicode data with a maximum length of 2E31 “1(or 2,147,483,647) characters.
Timestamp	DBTimestamp	DateTime ” Date and time data in the format yyyymmddhhmmss.
TinyInt	TinyInt	Byte ” An 8-bit unsigned integer.
UniqueIdentifier	Guid	Guid ” A globally unique identifier (or GUID).
-	UnsignedBigInt	UInt64 ” A 64-bit unsigned integer ( DBTYPE_UI8 ).
-	UnsignedInt	UInt32 ” A 32-bit unsigned integer ( DBTYPE_UI4 ).
-	UnsignedSmallInt	UInt16 ” A 16-bit unsigned integer ( DBTYPE_UI2 ).
-	UnsignedTinyInt	UInt8 ” An 8-bit unsigned integer ( DBTYPE_UI1 ).
VarBinary	VarBinary	Array of type Byte ” A variable-length stream of binary data ranging between 1 and 8,000 bytes. Note: Implicit conversion fails if the byte array is greater than 8,000 bytes. Explicitly set the object when working with byte arrays larger than 8,000 bytes.
VarChar	VarChar	String ” A variable-length stream of non-Unicode characters ranging between 1 and 8,000 characters.
Variant	Variant	Object ” A special data type that can contain numeric, string, binary, or date data as well as the SQL Server values Empty and Null, which is assumed if no other type is declared.
-	VarNumeric	Decimal ” A variable-length numeric value ( OleDbParameter only).
-	VarWChar	String ” A variable-length, null- terminated stream of Unicode characters ( OleDbParameter only).
-	WChar	String ” A null-terminated stream of Unicode characters ( DBTYPE_WSTR ).

ASP.NET DataSet

Table B.2. DataSet Properties

Property	Get/Set	Description
CaseSensitive	Get and Set	Gets or sets a value indicating whether string comparisons within DataTable objects are case-sensitive.
Container	Get	Gets the container for the component.
DataSetName	Get and Set	Gets or sets the name of the current DataSet .
DefaultViewManager	Get	Gets a custom view of the data contained by the DataSet that allows filtering, searching, and navigating using a custom DataViewManager .
DesignMode	Get	Gets a value indicating whether the component is currently in design mode.
EnforceConstraints	Get and set	Gets or sets a value indicating whether constraint rules are followed when attempting any update operation.
ExtendedProperties	Get	Gets the collection of custom user information.
HasErrors	Get	Gets a value indicating whether there are errors in any of the rows in any of the tables of this DataSet .
Locale	Get and Set	Gets or sets the locale information used to compare strings within the table.
Namespace	Get and Set	Gets or sets the namespace of the DataSet .
Prefix	Get and Set	Gets or sets an XML prefix that aliases the namespace of the DataSet .
Relations	Get	Gets the collection of relations that link tables and allow navigation from parent tables.
Site	Get and Set	Overridden. Gets or sets an System.ComponentModel.ISite for the DataSet.
Tables	Get	Gets the collection of tables contained in the DataSet .

Table B.3. DataSet Public Instance Methods

Method	Description
AcceptChanges	Commits all of the changes made to this DataSet since it was loaded or the last time AcceptChanges was called.
BeginInit	Begins the initialization of a DataSet that is used on a form or by another component. The initialization occurs at runtime.
Clear	Clears the DataSet of any data by removing all rows in all tables.
Clone	Clones the structure of the DataSet , including all DataTable schemas, relations, and constraints.
Copy	Copies both the structure and data for this DataSet .
Dispose	Overloaded. Releases the resources used by the MarshalByValueComponent .
EndInit	Ends the initialization of a DataSet that is used on a form or by another component. The initialization occurs at runtime.
Equals	Overloaded. Determines whether two Object instances are equal.
GetChanges	Overloaded. Gets a copy of the DataSet containing all changes made to it since it was last loaded, or since AcceptChanges was called.
GetHashCode	Serves as a hash function for a particular type, suitable for use in hashing algorithms and data structures like a hash table.
GetService	Gets the implementer of the IServiceProvider .
GetType	Gets the Type of the current instance.
GetXml	Returns the XML representation of the data stored in the DataSet .
GetXmlSchema	Returns the XSD schema for the XML representation of the data stored in the DataSet .
HasChanges	Overloaded. Gets a value indicating whether the DataSet has changes, including new, deleted, or modified rows.
InferXmlSchema	Overloaded. Infers the XML schema from the specified TextReader or file into the DataSet .
Merge	Overloaded. Merges this DataSet with a specified DataSet .
ReadXml	Overloaded. Reads XML schema and data into the DataSet.
ReadXmlSchema	Overloaded. Reads an XML schema into the DataSet .
RejectChanges	Rolls back all the changes made to the DataSet since it was created, or since the last time DataSet.AcceptChanges was called.
Reset	Resets the DataSet to its original state. Subclasses should override Reset to restore a DataSet to its original state.
ToString	Returns a String that represents the current Object .
WriteXml	Overloaded. Writes XML schema and data from the DataSet .
WriteXmlSchema	Overloaded. Writes the DataSet structure as an XML schema.

ASP.NET DataTable

Table B.4. DataTable Properties

Property	Get/Set	Description
CaseSensitive	Get and Set	Indicates whether string comparisons within the table are case-sensitive.
ChildRelations	Get	Gets the collection of child relations for this DataTable .
Columns	Get	Gets the collection of columns that belong to this table.
Constraints	Get	Gets the collection of constraints maintained by this table.
Container	Get	Gets the container for the component.
DataSet	Get	Gets the DataSet to which this table belongs.
DefaultView	Get	Gets a customized view of the table, which can include a filtered view or a cursor position.
DesignMode	Get	Gets a value indicating whether the component is currently in design mode.
DisplayExpression	Get and Set	Gets or sets the expression that will return a value used to represent this table in UI.
ExtendedProperties	Get	Gets the collection of custom user information.
HasErrors	Get	Gets a value indicating whether there are errors in any of the rows in any of the tables of the DataSet to which the table belongs.
Locale	Get and Set	Gets or sets the locale information used to compare strings within the table.
MinimumCapacity	Get and Set	Gets or sets the initial starting size for this table.
Namespace	Get and Set	Gets or sets the namespace for the DataTable .
ParentRelations	Get	Gets the collection of parent relations for this DataTable .
Prefix	Get and Set	Gets or sets the namespace for the XML representation of the data stored in the DataTable .
PrimaryKey	Get and Set	Gets or sets an array of columns that function as primary keys for the data table.
Rows	Get	Gets the collection of rows that belong to this table.
Site	Get and Set	Overridden. Gets or sets an System.ComponentModel.Site for the DataTable .
TableName	Get and Set	Gets or sets the name of the DataTable .

Table B.5. DataTable Public Instance Methods

Method	Description
AcceptChanges	Commits all the changes made to this table since the last time AcceptChanges was called.
BeginInit	Begins the initialization of a DataTable that is used on a form or used by another component. The initialization occurs at runtime.
BeginLoadData	Turns off notifications, index maintenance, and constraints while loading data.
Clear	Clears the DataTable of all data.
Clone	Clones the structure of the DataTable , including all DataTable schemas, relations, and constraints.
Compute	Computes the given expression on the current rows that pass the filter criteria.
Copy	Copies both the structure and the data for this DataTable .
Dispose	Overloaded. Releases the resources used by the MarshalByValueComponent .
EndInit	Ends the initialization of a DataTable that is used on a form or used by another component. The initialization occurs at runtime.
EndLoadData	Turns off notifications, index maintenance, and constraints while loading data.
Equals	Overloaded. Determines whether two Object instances are equal.
GetChanges	Overloaded. Gets a copy of the DataTable containing all changes made to it since it was last loaded, or since AcceptChanges was called.
GetErrors	Gets an array of DataRow objects that contain errors.
GetHashCode	Serves as a hash function for a particular type, suitable for use in hashing algorithms and data structures like a hash table.
GetService	Gets the implementer of the IServiceProvider .
GetType	Gets the Type of the current instance.
ImportRow	Copies a DataRow , including original and current values, DataRowState values, and errors, into a DataTable .
LoadDataRow	Finds and updates a specific row. If no matching row is found, a new row is created using the given values.
NewRow	Creates a new DataRow with the same schema as the table.
RejectChanges	Rolls back all changes that have been made to the table since it was loaded, or the last time AcceptChanges was called.
Select	Overloaded. Gets an array of DataRow objects.
ToString	Overridden. Gets the TableName and DisplayExpression , if there is one as a concatenated string.

RowStates of a DataRow

Table B.6. DataRow.RowState (uses DataRowState enumeration)

RowState	Description
Added	The row has been added to a DataRowCollection , and AcceptChanges has not been called.
Deleted	The row was deleted using the Delete method of the DataRow .
Detached	The row has been created but is not part of any DataRowCollection . A DataRow is in this state immediately after it has been created and before it is added to a collection, or if it has been removed from a collection.
Modified	The row has been modified and AcceptChanges has not been called.
Unchanged	The row has not changed since AcceptChanges was last called.

DataColumn ForeignKeyContraint

Table B.7. ForeignKeyConstraint (uses Rule enumeration)

Action	Description
Cascade	Delete or update related rows. This is the default.
None	No action taken on related rows.
SetDefault	Set values in related rows to the value contained in the DefaultValue property.
SetNull	Set values in related rows to DBNull .

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