Xbasic

SQL::ResultSet Object

Description

SQL::ResultSet Object properties and methods.

Discussion

When a SQL query returns one or more rows of data, you can use the ResultSet object to get the description of the result set and to navigate within the rows of the results to retrieve the data.

Name: Description
More about the SQL::ResultSet Object: While working in the Interactive window, after creating the rs SQL::ResultSet object, you could type.

Using the StreamingMode property

In this example, we are using the NextRow() function to test for the existence of data. Normally, we would not want to do this as it would read the data values of the first row and not include them in the output string. Setting StreamingMode to .t. turns off the data fetch so the row data is still available.

The script below shows what happens when you reposition the result set prior to calling a streaming mode function (such as ToString(), ToOpenTable()). Note that when in non-streaming mode, the data for the row positioned to is loaded into memory. This can cause the first row to be omitted when a streaming function is called. To avoid this, if you call positioning functions such as NextRow() or GoToRow(), you will want to set the StreamingMode property to true.

If you actually retrieve data using the Data() or DataIsNull() function, you must re-execute the query before calling a streaming function.

dim cn as sql::Connection
?cn.open("::Name::AADemo-Northwind")
= .T.

?cn.execute("select * from categories")
= .T.

'nextrow() moves you to row 1 AND fetches the data into local buffers so row 1 is excluded
?cn.resultset.nextrow()
= .T.

?cn.resultset.tostring()
=
2	Condiments	Sweet and savory sauces, relishes, spreads, and seasonings	<Binary Data>
3	Confections	Desserts, candies, and sweet breads	<Binary Data>
4	Dairy Products	Cheeses	<Binary Data>
5	Grains/Cereals	Breads, crackers, pasta, and cereal	<Binary Data>
6	Meat/Poultry	Prepared meats	<Binary Data>
7	Produce	Dried fruit and bean curd	<Binary Data>
8	Seafood	Seaweed and fish	<Binary Data>

?cn.execute("select * from categories")
= .T.

'Setting StreamingMode to .t. causes the NextRow() call to skip reading the data.
cn.ResultSet.StreamingMode = .t.
?cn.resultset.nextrow()
= .T.


?cn.resultset.tostring()
= 1	Beverages	Soft drinks, coffees, teas, beers, and ales	<Binary Data>
2	Condiments	Sweet and savory sauces, relishes, spreads, and seasonings	<Binary Data>
3	Confections	Desserts, candies, and sweet breads	<Binary Data>
4	Dairy Products	Cheeses	<Binary Data>
5	Grains/Cereals	Breads, crackers, pasta, and cereal	<Binary Data>
6	Meat/Poultry	Prepared meats	<Binary Data>
7	Produce	Dried fruit and bean curd	<Binary Data>
8	Seafood	Seaweed and fish	<Binary Data>

?cn.execute("select * from categories where true = false")
= .T.

?cn.resultset.nextrow()
= .F.

?cn.resultset.tostring()
= ""

Properties

ActiveLinkDBFRowSyntaxCharacter

ActiveLinkDBFRowSyntax property

CallResultSQL::CallResult

Detailed status of the result of the call.

ColumnCountNumeric

Default = 0. The number of columns in the result set.

ColumnInfoSQL::DataTypeInfo[]

An array of SQL::DataTypeInfo column descriptions.

CurrentRowSQL::Row

Returns the current row as an object.

CurrentRowIndexNumeric

Default = 0. The number of the current row.

DBFRowSyntaxCharacter

Default = "". The syntax required to create an Alpha Anywhere .DBF table with the same columns.

RowCountNumeric

Default = 0. The number of rows in the result set. -1 If not known. Do not rely on this value, as not all drivers support it. Walk the ResultSet with .NextRow() instead.

SizeToFitLogical

When set to true, DBFRowSyntax will return lengths adjusted based on the actual data.

Notes:

1. Call UpdateStatistics before getting the DBFRowSyntax.

2. If the longest column is zero length, the default length is 15.

Size to fit will limit the size of inserted or updated fields on imported or linked tables to the maximum size of the previous values.

StreamingModeLogical

When set to true, fetches will NOT populate internal data values.

Notes:

1. This is an advanced feature and should be used only in combination with streaming functions such as ToString and ToOpenTable to turn off autofetching of values.

2. Many of the streaming functions will reset the value of this property to false after completion. Set this property before calling any function that requires it to be set to .t.

See "Using the StreamingMode property" for more information.

TableInfoSQL::TableInfo[]

Not always available. An array of SQL::TableInfo table descriptions returned by the query.

TableInfoCountNumeric

The number of elements in .TableInfo.

QuerySourceCharacter

QuerySource property

QueryArgumentsCharacter

QueryArguments property

Methods

ColumnNumber Method: Get the number of the column named.
Data Method: Get the data for the column name or index specified.
DataAsGeography Method: Takes data retrieved from a database and returns a .NET Geography object.
DataIsNull Method: Determine whether a given element is Null.
ExecutePostProcess Method: Execute portable SQL against a SQL::ResultSet, Allows for filtering after fetching a result set.
FetchPage Method: Fetch a block of one or more rows into a local cache table. Note: This function is an advanced user feature and requires some understanding of caching for SQL.
FormatData Method: Format the data for the column name, index or definition specified.
GoToRow Method: Position to the row requested (backward movement is not supported by all databases).
NextResult Method: Position to the next set of rows in the ResultSet (applies only when multiple results are returned).
NextRow Method: The NextRow() method fetches the next row in the SQL::ResultSet.
ToCSV Method: Convert a ResultSet to Comma Separated Variable format.
ToCSVFile Method: Write a ResultSet to a file in Comma Separated Variable (CSV) format.
ToDBF Method: Create a local copy of the result set in a .DBF table
ToExcel Method: Convert ResultSet to an Excel 2003 format (.xls) or 2007 format (.xlsx) file.
ToFormattedString Method: Copy the ResultSet to a string.
ToGridComponentDataObject Method: Convert the ResultSet to a Grid Component DataObject data and field arrays.
ToJSON Method: Convert a ResultSet to a JSON formatted string.
ToJSONFile Method: Convert a ResultSet to JSON object and store in TargetFile
ToJSONObjectSyntax Method: Convert a ResultSet to JSON object syntax.
ToOpenTable Method: Fetch data from a result set to an open .DBF table
ToPropertyArray Method: Convert the ResultSet to a property array.
ToString Method: Copy the ResultSet to a string.
ToTableInfo Method: Return the column definitions as a single SQL::TableInfo.
ToXML Method: Convert ResultSet an XML formatted string.