Thinking in C# phần 6

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Nội dung chi tiết: Thinking in C# phần 6

Thinking in C# phần 6

relational table data and XML) as well as making it much easier to program widely-distributed database applications. However, this model increases the

Thinking in C# phần 6 e possibility that two users will make incompatible modifications to related data - they'll both reserve the last seat on the flight, one will mark an

issue as resolved while the other will expand the scope of the investigation, etc. So even a minimal introduction to ADO.NET requires some discussion Thinking in C# phần 6

of the issues of concurrency violations.Getting a handle on data with DataSetThe DataSet class is the root of a relational view of data. A DataSet ha

Thinking in C# phần 6

s DataTables, which have DataColuinns that define the types in Data Rows. The relational database model was introduced by Edgar F. Codd in the early 1

relational table data and XML) as well as making it much easier to program widely-distributed database applications. However, this model increases the

Thinking in C# phần 6 ization of these concepts and others such such as normalization (a process by which redundant data is eliminated and thereby ensuring the correctness

and consistency of edits) was one of the great landmarks in the history of computer science.While normally one creates a DataSet based on existing dat Thinking in C# phần 6

a, it's possible to create one from scratch, as this example shows://:clo:BasicDataSetOperations.es using System;using System.Data;class BasicDataSetO

Thinking in C# phần 6

perations {public static void Main (string[] args){Dataset ds BuildDataSet0;PrintDataSetCharacteristics(ds);1private static DataSet BuildDataSet () {

relational table data and XML) as well as making it much easier to program widely-distributed database applications. However, this model increases the

Thinking in C# phần 6 typeof(string)> ;auTable.Columns.Add(nameCol);DataRow larryRow - auTable.NewRow();422Thinking in c*www.ThinkingIn.NETlarryRow["Name"] - "Larry";auTab

le.Rows.Add(larryRow);DataRow bruceRow - auTable.NewRow();bruceRow["Name"] "Bruce";auTable.Rows.Add(bruceRow);return ds;1private static void FrintDat Thinking in C# phần 6

aSetCharacteristics{DataSet ds){Console.wrlteLine("Dataset \"{0}\" has (1} tables", ds.DataSetName, ds.Tables.Count);foreachtDataTable table in ds.Tab

Thinking in C# phần 6

les)(Console.WriteLine("Table \"{0}\" has (1) columns",table.TableName, table.Columns.Count);foreach (DataColumr. col in table .Columns) {

relational table data and XML) as well as making it much easier to program widely-distributed database applications. However, this model increases the