Cast Dialog v8
Use the Cast
dialog to define a cast. A cast specifies how to convert a value from one data type to another.
The Cast
dialog organizes the development of a cast through the following dialog tabs: General
and Definition
. The SQL
tab displays the SQL code generated by dialog selections.
Use the fields in the General
tab to identify the cast:
- The
Name
field is disabled. The name that will be displayed in theBrowser
tree control is theSource
type concatenated with theTarget
type, and is generated automatically when you make selections on theCast
dialogDefinition
tab. - Store notes about the cast in the
Comment
field.
Click the Definition
tab to continue.
Use the fields in the Definition
tab to define parameters:
- Use the drop-down listbox next to
Source type
to select the name of the source data type of the cast. - Use the drop-down listbox next to
Target type
to select the name of the target data type of the cast. - Use the drop-down listbox next to
Function
to select the function used to perform the cast. The function's result data type must match the target type of the cast. - Move the
Context
switch to theImplicit
position if the cast is implicit. By default, a cast can be invoked only by an explicit cast request. If the cast is markedImplicit
then it can be invoked implicitly in any context, whether by assignment or internally in an expression.
Click the SQL
tab to continue.
Your entries in the Cast
dialog generate a SQL command (see an example below). Use the SQL
tab for review; revisit or switch tabs to make any changes to the SQL command.
Example
The following is an example of the sql command generated by user selections in the Cast
dialog:
The cast uses a function named int4(bigint)
to convert a biginteger data type to an integer.
- Click the
Info
button (i) to access online help. View context-sensitive help in theTabbed browser
, where a new tab displays the PostgreSQL core documentation. - Click the
Save
button to save work. - Click the
Cancel
button to exit without saving work. - Click the
Reset
button to restore configuration parameters.