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5.13 PLVgen: PL/SQL Code Generator

The PLVgen (PL/Vision GENerator) package provides a set of procedure you can use to generate your own PL/SQL code. See Chapter 16, PLVgen: Generating PL/SQL Programs for details.

5.13.1 Package constants

c_indent CONSTANT INTEGER := 0;

The default initial indentation of generated code.

c_incr_indent CONSTANT INTEGER := 3;

The default incremental indentation of generated code.

c_literal CONSTANT CHAR(1) := '=';

The character used to indicate that the default value for the string function is not to be evaluated before placing in the function definition.

c_def_length CONSTANT INTEGER := 100;

The default length for a string function's local variable.

c_none CONSTANT VARCHAR2(1) := 'N';

Indicates that no blank lines are to be placed before or after the current line of code.

c_before CONSTANT VARCHAR2(1) := 'B';

Indicates that a blank line is to be placed before the current line of code.

c_after CONSTANT VARCHAR2(1) := 'A';

Indicates that a blank line is to be placed after the current line of code.

c_both CONSTANT VARCHAR2(2) := 'BA';

Indicates that a blank line is to be placed both before and after the current line of code.

5.13.2 Setting the indentation

PROCEDURE set_indent
(indent_in IN NUMBER,
incr_indent_in IN NUMBER := c_incr_indent);

Sets the initial and incremental indentation.

FUNCTION indent RETURN NUMBER;

Returns the current value for initial indentation.

FUNCTION incr_indent RETURN NUMBER;

Returns the current value for incremental indentation.

5.13.3 Setting the author

PROCEDURE set_author (author_in IN VARCHAR2);

Assigns a value for the author string used in program headers.

FUNCTION author RETURN VARCHAR2;

Returns the current author string.

5.13.4 Toggles affecting generated code

PLVgen offers a large selection of toggles or on-off switches, which you can use to modify the content of code generated by this package. Each toggle has a "turn on" procedure, a "turn off" procedure, and a function returning the current state of the toggle (on or off).

PROCEDURE usetrc;
PROCEDURE nousetrc;
FUNCTION using_trc RETURN BOOLEAN;

Controls inclusion of the PLVtrc startup and terminate procedures.

PROCEDURE useexc;
PROCEDURE nouseexc;
FUNCTION using_exc RETURN BOOLEAN;

Controls inclusion of PLVexc exception handlers in exception sections of programs.

PROCEDURE usehdr;
PROCEDURE nousehdr;
FUNCTION using_hdr RETURN BOOLEAN;

Controls inclusion of program headers in packages, procedures, and functions.

PROCEDURE usecmnt;
PROCEDURE nousecmnt;
FUNCTION using_cmnt RETURN BOOLEAN;

Controls inclusion of comment lines in generated code.

PROCEDURE usehlp;
PROCEDURE nousehlp;
FUNCTION using_hlp RETURN BOOLEAN;

Controls inclusion of help text stubs and generation of the help procedure in packages.

PROCEDURE usecor;
PROCEDURE nousecor;
FUNCTION using_cor RETURN BOOLEAN;

Controls inclusion of code required to CREATE OR REPLACE program units.

PROCEDURE useln;
PROCEDURE nouseln;
FUNCTION usingln RETURN BOOLEAN;

Controls inclusion of line numbers in prefix of generated code.

PROCEDURE usemin;

Turns off all the above toggles.

PROCEDURE usemax;

Turns on all the above toggles.

5.13.5 Help generators

PROCEDURE helpproc
(prog_in IN VARCHAR2 := NULL, indent_in IN INTEGER := 0);

Generates a procedure that gives main-topic help for the specified program unit.

PROCEDURE helptext (context_in IN VARCHAR2 := PLVhlp.c_main);

Generates a comment block in the correct format to be used as online help text with the PLVhlp package.

5.13.6 Generating a package

PROCEDURE pkg (name_in IN VARCHAR2);

Generates the skeleton structure for a package's specification and body.

5.13.7 Generating a procedure

PROCEDURE proc
(name_in IN VARCHAR2,
params_in IN VARCHAR2 := NULL,
exec_in IN VARCHAR2 := NULL,
incl_exc_in IN BOOLEAN := TRUE,
indent_in IN INTEGER := 0,
blank_lines_in IN VARCHAR2 := c_before);

Generates a procedure of the specified name. You can also provide a parameter list and one or more executable lines. Finally, you can decide to include an exception section, indent the code, and perform blank-line processing.

5.13.8 Generating functions

A function has a RETURN datatype. PLVgen allows you to generate string, numeric, date, and Boolean functions. You can also supply literal and symbol default values. As a result, the func procedure is overloaded as shown:

PROCEDURE func
(name_in IN VARCHAR2,
datadesc_in VARCHAR2,
defval_in IN VARCHAR2 := NULL,
length_in IN INTEGER := c_def_length,
incl_exc_in IN BOOLEAN := TRUE);

Generates a string function (since the datatype for the datdesc_in parameter is VARCHAR2).

PROCEDURE func
(name_in IN VARCHAR2,
datadesc_in datatype ,
defval_in IN datatype := NULL,
incl_exc_in IN BOOLEAN := TRUE);

Generates a function of the specified datatype , which is either NUMBER, DATE, or BOOLEAN. Notice that the default has the same datatype as the datadesc_in parameter. This is a default value that is evaluated as a literal.

PROCEDURE func
(name_in IN VARCHAR2,
datadesc_in datatype ,
defval_in IN VARCHAR2,
incl_exc_in IN BOOLEAN := TRUE);

Generates a function of the specified datatype , which is either NUMBER, DATE, or BOOLEAN. Notice that the default in this version is a string. When you use this format, the default value is treated as an expression that is not evaluated.

5.13.9 Generating get-and-set routines

Get-and-set routines provide a programmatic layer of code around a private data structure. As a result, the get-and-sets or "gas" generators have associated with them a datatype. PLVgen allows you to generate string, numeric, date, and Boolean get-and-sets. You can also supply literal and symbol default values. As a result, the gas procedure is overloaded with the following flavors:

PROCEDURE gas
(name_in IN VARCHAR2,
valtype_in VARCHAR2,
defval_in IN VARCHAR2 := NULL,
length_in IN INTEGER := c_def_length);

Generates a string function (since the datatype for the datdesc_in parameter is VARCHAR2).

PROCEDURE gas
(name_in IN VARCHAR2,
valtype_in datatype ,
defval_in IN datatype := NULL);

Generates get-and-sets of the specified datatype , which is either NUMBER, DATE, or BOOLEAN. Notice that the default has the same datatype as the datadesc_in parameter. This is a default value that is evaluated as a literal.

PROCEDURE gas
(name_in IN VARCHAR2, valtype_in datatype ,
defval_in IN VARCHAR2);

Generates get-and-sets of the specified datatype , which is either NUMBER, DATE, or BOOLEAN. Notice that the default in this version is a string. When you use this format, the default value is an expression that is not evaluated.

PROCEDURE toggle (name_in IN VARCHAR2 := NULL);

Generates a variation of get-and-set based on a Boolean toggle. If you do not give a name, turn_on and turn_off are used as the on-off procedure names.

5.13.10 Miscellaneous code generators

PROCEDURE curdecl
(cur_in IN VARCHAR2,
ind_in IN INTEGER := 0,
table_in IN VARCHAR2 := NULL,
collist_in IN VARCHAR2 := NULL,
gen_rec_in IN BOOLEAN := TRUE);

Generates a cursor declaration with the SQL statement formatted for maximum readability.

PROCEDURE cfloop (table_in IN VARCHAR2);

Generates a cursor FOR loop and framework for a cursor declaration.

PROCEDURE recfnd (table_in IN VARCHAR2);

Generates a function that returns TRUE if a record is found, FALSE otherwise.

PROCEDURE timer (plsql_in IN VARCHAR2);

Generates a function that returns TRUE if a record is found, FALSE otherwise.


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