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#!/usr/bin/python
# sql2dot.py
#
# Creates table graphics by parsing SQL table DML commands and
# generating DOT language output.
#
# Adapted from a post at https://energyblog.blogspot.com/2006/04/blog-post_20.html.
#
sampleSQL = """
create table student
(
student_id integer primary key,
firstname varchar(20),
lastname varchar(40),
address1 varchar(80),
address2 varchar(80),
city varchar(30),
state varchar(2),
zipcode varchar(10),
dob date
);
create table classes
(
class_id integer primary key,
id varchar(8),
maxsize integer,
instructor varchar(40)
);
create table student_registrations
(
reg_id integer primary key,
student_id integer,
class_id integer
);
alter table only student_registrations
add constraint students_link
foreign key
(student_id) references students(student_id);
alter table only student_registrations
add constraint classes_link
foreign key
(class_id) references classes(class_id);
""".upper()
from pyparsing import (
Literal,
Word,
delimitedList,
alphas,
alphanums,
OneOrMore,
ZeroOrMore,
CharsNotIn,
replaceWith,
)
skobki = "(" + ZeroOrMore(CharsNotIn(")")) + ")"
field_def = OneOrMore(Word(alphas, alphanums + "_\"':-") | skobki)
def field_act(s, loc, tok):
return ("<" + tok[0] + "> " + " ".join(tok)).replace('"', '\\"')
field_def.setParseAction(field_act)
field_list_def = delimitedList(field_def)
def field_list_act(toks):
return " | ".join(toks)
field_list_def.setParseAction(field_list_act)
create_table_def = (
Literal("CREATE")
+ "TABLE"
+ Word(alphas, alphanums + "_").setResultsName("tablename")
+ "("
+ field_list_def.setResultsName("columns")
+ ")"
+ ";"
)
def create_table_act(toks):
return (
""""%(tablename)s" [\n\t label="<%(tablename)s> %(tablename)s | %(columns)s"\n\t shape="record"\n];"""
% toks
)
create_table_def.setParseAction(create_table_act)
add_fkey_def = (
Literal("ALTER")
+ "TABLE"
+ "ONLY"
+ Word(alphanums + "_").setResultsName("fromtable")
+ "ADD"
+ "CONSTRAINT"
+ Word(alphanums + "_")
+ "FOREIGN"
+ "KEY"
+ "("
+ Word(alphanums + "_").setResultsName("fromcolumn")
+ ")"
+ "REFERENCES"
+ Word(alphanums + "_").setResultsName("totable")
+ "("
+ Word(alphanums + "_").setResultsName("tocolumn")
+ ")"
+ ";"
)
def add_fkey_act(toks):
return """ "%(fromtable)s":%(fromcolumn)s -> "%(totable)s":%(tocolumn)s """ % toks
add_fkey_def.setParseAction(add_fkey_act)
other_statement_def = OneOrMore(CharsNotIn(";")) + ";"
other_statement_def.setParseAction(replaceWith(""))
comment_def = "--" + ZeroOrMore(CharsNotIn("\n"))
comment_def.setParseAction(replaceWith(""))
statement_def = comment_def | create_table_def | add_fkey_def | other_statement_def
defs = OneOrMore(statement_def)
print("""digraph g { graph [ rankdir = "LR" ]; """)
for i in defs.parseString(sampleSQL):
if i != "":
print(i)
print("}")
|
