Vb.net what is a datatable

It is often used alongside SQL databases. Type details. DataTable has columns and rows properties, and we use these like other VB.

NET collections. DataTable is an in-memory representation of structured data. First example. We define GetTable—this returns a new DataTable.

When the GetTable function is invoked, it creates a new DataTable and adds 3 columns to it. Columns These are named with a string argument and a Type argument. They have different types. GetTable In a DataTable, each column allows a specific type of data. The GetTable method adds 5 rows to the DataTable. Tip The arguments to the Rows. Add method are of the types specified in the columns. To use this property, enter the object name of the table in the square brackets of the DataTableCollection.

Item property. Instead of locating a table by its name, you can use its index from the collection. To do this, you can use the second version of the DataTableCollection. This property expects as argument the index of the table in the DataSet.

If you provide an index below or beyond the number of tables in the set, the compiler would throw an IndexOutOfRangeException exception. To avoid this, you can request the index of the table. To do this, call the DataTableCollection. IndexOf method. It is overloaded with two versions.

One of the versions takes as argument the variable name of the table. The syntax of this method is:. Instead of using the variable name of the table, you can locate it using its object name. To do this, call the following version of the IndexOf method:. When the tables of a DataSet object have been created, you can get their list as an array using the DataTableCollection. List property. This property returns an ArrayList type of list. Instead of directly locating a table, you may be interested to know whether a particular table exists in the DataSet.

To check this, you can call the DataTableCollection. Contains method. This method expects the object name of a table as argument. If the table exists in the collection, this method returns true. Removing Tables If you happen to have a table you don't need anymore or whose role is undefined in your application, you can delete that table. This operation is supported by the DataTableCollection. Remove method that is overloaded with two versions.

To locate a table using its variable declared name and delete it, you can use the following version:. This version expects the name that was used to declare the DataTable object. If the table exists in the DateSet. And these tables often reside in databases. In the. Columns, rows. Used often in VB. NET programs, DataTable has columns and rows properties. DataTable is an in-memory representation of structured data—such as that read from a database.

A program. We define GetTable—this returns a new DataTable. When the GetTable function is invoked, it creates a new DataTable and adds four columns to it. Columns: These are named with a string argument and a Type argument. They have different types. GetTable: In a DataTable, each column allows a specific type of data. The GetTable method adds five rows to the DataTable. Tip: The arguments to the Rows. Connect and share knowledge within a single location that is structured and easy to search.

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