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VS 2008 and .NET Framework 3.5 SP1
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25.8.2008 10:56:50
- Filed under :
C#
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Asp.net
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Ado.net
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Microsoft .NET Framework 3.5 Service Pack 1
Microsoft .NET Framework 3.5 Service Pack 1 is a full cumulative update
that contains many new features building incrementally upon .NET
Framework 2.0, 3.0, 3.5, and includes cumulative servicing updates to
the .NET Framework 2.0 and .NET Framework 3.0 subcomponents.
Microsoft Visual Studio 2008 Service Pack 1
Improved WPF designers, SQL Server 2008 support, ADO.NET Entity
Designer,Richer JavaScript support, enhanced AJAX and data tools, and
Web site deployment improvements and so on.
For more details : http://msdn.microsoft.com/en-us/vstudio/products/cc533447.aspx
Keywords : Service Packs, VS 2008 SP1, .NET Framework SP1
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with 0 comments
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Using MissingSchemaAction.AddWithKey
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25.1.2007 17:28:09
- Filed under :
Ado.net
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Adding schema information to a DataSet before filling it with data
ensures that primary key constraints are included with the DataTable
objects in the DataSet. As a result, when additional calls to fill the
DataSet are made, the primary key column information is used to match
new rows from the data source with current rows in each DataTable, and
current data in the tables is overwritten with data from the data
source.
Without the schema information, the
new rows from the data source are appended to the DataSet, resulting in
duplicate rows.
Example :
DataSet
custDataSet = new DataSet();
custAdapter.MissingSchemaAction =
MissingSchemaAction.AddWithKey;
custAdapter.Fill(custDataSet,
"Customers");
Using FillSchema or
setting the MissingSchemaAction to
AddWithKey requires extra processing at the data
source to determine primary key column information. This additional
processing can hinder performance. If you know the primary key
information at design time, we recommend that you explicitly specify
the primary key column or columns in order to achieve optimal
performance.
PS : You should use AddWithKey option if you want to handle "Constraint Exception". I use it in my little replication engine program like this ;
using (OracleCommand command = new OracleCommand())
{
command.CommandText = "SELECT * FROM " + tableName + " WHERE " + primaryKeyField + "=" + drow[primaryKeyField];
command.Connection = connection;
adapter.SelectCommand = command;
adapter.MissingSchemaAction = MissingSchemaAction.AddWithKey;
DataTable dt = new DataTable();
adapter.Fill(dt);
// Commandbuilder
using (OracleCommandBuilder builder = new OracleCommandBuilder())
{
builder.DataAdapter = adapter;
// INSERT
DataRow dr = dt.NewRow();
foreach (DataColumn dc in dt.Columns)
{
dr[dc.ColumnName] = drow[dc.ColumnName];
}
try
{
dt.Rows.Add(dr);
}
catch (ConstraintException)
{
// UPDATE
DataRow row = dt.Rows[0];
foreach (DataColumn dc in dt.Columns)
{
row[dc.ColumnName] = drow[dc.ColumnName];
}
}
adapter.Update(dt);
}
}
Related Terminology :
MissingSchemaAction.AddWithKey, Primary Key, Constraint Exception
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with 0 comments
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Batch Updates in ADO.NET 2.0
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30.8.2006 01:11:49
- Filed under :
Ado.net
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ADO.NET 2.0 has introduced the concept of Batch Updates, which allows you to designate the number of commands sent to the database at a given time. If used correctly, this can increase the performance of your data access layer by reducing the number of roundtrips to the database.When you updated a database using the DataAdapter in .NET 1.1 each
command was sent to the database one at a time. This caused a lot of
roundtrips to the database. The DataAdapter has an UpdateBatchSize Property that allows you to set the number of commands that will be sent to the database with each request.
- UpdateBatchSize = 1, disables batch updates
- UpdateBatchSize = X where X > 1, sends x statements to the database at a time
- UpdateBatchSize = 0, sends the maximum number of statements at a time allowed by the server
...
using (OracleCommandBuilder cm = new OracleCommandBuilder(da))
{
da.UpdateBatchSize = 0;
da.Update(dt);
} PS. Oracle supports this features in Oracle Data Provider for .NET 10.2.0.2.20 Production
Related Terminology : Batch Update, ADO.NET 2.0, ODP.NET Release
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with 0 comments
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Memo field truncated
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23.8.2006 06:38:41
- Filed under :
Ado.net
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In any Memo field that contains more than 1024 characters
is truncated to 1024 characters when you insert some text to MS Access via web user interface.
Please check your dataset desinger file (ie. DatasetProducts.Designer.cs)this._adapter.InsertCommand.Parameters.Add(new System.Data.OleDb.OleDbParameter("Content", System.Data.OleDb.OleDbType.WChar, 1024,
System.Data.ParameterDirection.Input, ((byte)(0)), ((byte)(0)),
"Content", System.Data.DataRowVersion.Current, false, null)); and replace 1024 to what you want (ie. 536870910)
Related Terminology : MS Access, TableAdapters, Insert Command, Update Command
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with 0 comments
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System.ArgumentException
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23.8.2006 05:38:58
- Filed under :
Ado.net
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System.ArgumentException: This constraint cannot be enabled as not all values have corresponding parent values.
This
exception occurs if your lookup query does not return all the values
that are used in the master-table. Some developers suggest that you
enable referential integrity (ie, add a relation) in the database
betweeen the lookup table and the master table; but this shouldnt
prevent this scenario.
When I set "createConstraints" parameter to "false" then the error is disappeared.ds.Relations.Add("myrelation", ds.Tables[0].Columns["ArticleID"], ds.Tables[1].Columns["ArticleID"],false); Because,
the exception is not related to Access. Remember the DataSet is
disconnected and is independent from Access. This error can occur when
a parent-child relationship is created and then children are loaded
into the DataSet without the parent existing (whether or not the parent
exists in the database is irrelevant - it has to exist in the DataSet
as well because the DataSet is disconnected from the database)
Related Terminology : MS Access, Repeater, Dataset Relation
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with 0 comments
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