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Blocks & Variables
Anonymous block DECLARE section Variable assignment Constants Anchored %TYPE Anchored %ROWTYPE Nested blocks Labels NULL statement DBMS_OUTPUT
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Procedures & Functions
CREATE PROCEDURE IN parameter OUT parameter IN OUT parameter CREATE FUNCTION RETURN statement Default parameters Named notation Local subprogram Overloading
Packages
Package specification Package body Public procedure Private procedure Package variable Package initialization Package constant Package cursor Package overloading Forward declaration
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PL/SQL / Packages

Forward declaration

Learn Forward declaration in PL/SQL through a focused explanation, a dedicated construct-specific example, an engineering boundary, and a mastery check.

10 min read • Intermediate

Forward declaration is an atomic PL/SQL topic inside Packages. This lesson focuses on how the Forward declaration construct is written, what it changes, and when it is the right tool.

Trace the example line by line. Identify the exact syntax for Forward declaration, the input state before it runs, and the resulting value, control flow, database state, hardware behavior, or runtime effect afterward. Neighboring lessons use different constructs rather than renamed copies of this one.

Topic-specific example

plsql-06-10-forward-declaration.sql
plsql Try It Live 
DECLARE PROCEDURE second; PROCEDURE first IS BEGIN second; END; PROCEDURE second IS BEGIN DBMS_OUTPUT.PUT_LINE('second'); END; BEGIN first; END; /
Edge case / engineering note

For Forward declaration, test the boundary that belongs to this exact feature rather than a generic failure case. Check invalid or empty input, NULL/unknown state, numeric limits, transaction or exception behavior, synthesis/runtime constraints, ownership/permission rules, or backtracking/control-flow effects where they apply.

Content source & attribution
Original Syntaxis Content · Original Syntaxis Content

Lesson quizzes

Forward declaration Mastery Check →
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