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DBCon

function DBCon: TvxDBCon;

Example​

procedure ScriptEvent(var Value: variant);
var
  Connection: TvxDBCon;
begin
  Connection := DBCon;
  if Connection <> nil then
    Value := Connection.ModuleName
  else
    Value := Null;
end;

Usage​

DBCon returns the first database connection currently attached to the script's Source definition.

Value and availability

The result is FSource.DBCons[0].DBCon when FSource is assigned and DBConCount > 0; otherwise it is nil. The function does not search later links, choose by name or create a connection.

Ownership, errors and performance

Velox owns the returned TvxDBCon; never free it or retain it beyond the current execution. The getter is constant-time and performs no database I/O. Its explicit absent-context path returns nil. Errors from later connection operations follow the called member and propagate as documented there.

Additional Technical Info​

DBCon is a function-backed context value that returns the current Source data definition's first database connection object. It re-evaluates the Source on each call rather than returning a connection cached when the script compiled.

Implementation

EngineCompile registers TvxScripter.DBCon as a method in the Modules variable category. Its body checks the current FSource and its connection count every time. The source comment explains that this avoids retaining stale database objects when the database changes for each action execution.

Behaviour and edge cases

  • The result can be nil. Check once and retain the local reference for the immediate operation, as in the example.
  • Only index zero is returned when Source has multiple database connections. Use APIs on the data definition when another link is required.
  • A non-nil result does not prove that the connection is open, reachable, authorized or correctly configured.
  • Repeated DBCon calls can observe a different current object if host context changes; do not assume identity across executions.
  • Calling the accessor does not connect to the database by itself, but methods/properties used on the returned object can perform database work.

Related entries

  • Source is the data definition inspected by this accessor.
  • FileCon returns a separately injected file connection and does not inspect Source.
Created 2026-07-15