TkTreeCtrl is a powerfull and very fast widget, well suited to render data stored in a SQLite database.
Below is a quick and dirty example for rendering SQLite data in TkTreeCtrl + paging the recordset in a very basic way.
WARNING : the following script will create a SQLite db file "Presidents" (12 Ko) in the current working directory.
package require Tk
package require sqlite3
package require treectrl
wm withdraw .
# PART ONE : data storage
# Open connection to Presidents db file + create this file if non existent
sqlite3 db1 Presidents
# Create "Presidents" table and populate it
# (middle names/initials omited)
db1 eval {CREATE TABLE IF NOT EXISTS Presidents(\
Country VARCHAR(2) DEFAULT 'US' CHECK(Country <> ''),
FirstName TEXT NOT NULL CONSTRAINT Check_FirstName CHECK(FirstName <> ''),
LastName TEXT NOT NULL CONSTRAINT Check_FirstName CHECK(FirstName <> ''),
BirthDate VARCHAR(10) NOT NULL CONSTRAINT Check_BirthDate CHECK(length(BirthDate) = 10), /* ISO8601 format */
PRIMARY KEY (FirstName, LastName, BirthDate)\
)}
db1 eval {INSERT OR IGNORE INTO Presidents ( FirstName, LastName, BirthDate )
VALUES ( 'George' , 'Washington', '1732-02-22' ),
( 'John' , 'Adams' , '1735-10-30' ),
( 'Thomas' , 'Jefferson' , '1743-04-13' ),
( 'James' , 'Madison' , '1751-03-16' ),
( 'James' , 'Monroe' , '1758-04-28' ),
( 'Andrew' , 'Jackson' , '1767-03-15' ),
( 'John' , 'Adams' , '1767-07-11' ),
( 'William' , 'Harrison' , '1773-02-09' ),
( 'Martin' , 'Van Buren' , '1782-12-05' ),
( 'John' , 'Tyler' , '1790-03-29' ),
( 'James' , 'Polk' , '1795-11-02' ),
( 'Zachary' , 'Taylor' , '1784-11-24' ),
( 'Millard' , 'Fillmore' , '1800-01-07' ),
( 'Franklin' , 'Pierce' , '1804-11-23' ),
( 'James' , 'Buchanan' , '1791-04-23' ),
( 'Abraham' , 'Lincoln' , '1809-02-12' ),
( 'Andrew' , 'Johnson' , '1808-12-29' ),
( 'Ulysses' , 'Grant' , '1822-04-27' ),
( 'Rutherford', 'Hayes' , '1822-10-04' ),
( 'James' , 'Garfield' , '1831-11-19' ),
( 'Chester' , 'Arthur' , '1829-10-05' ),
( 'Grover' , 'Cleveland' , '1837-03-18' ),
( 'Benjamin' , 'Harrison' , '1833-08-20' ),
( 'William' , 'McKinley' , '1843-01-29' ),
( 'Theodore' , 'Roosevelt' , '1858-10-27' ),
( 'William' , 'Taft' , '1857-09-15' ),
( 'Woodrow' , 'Wilson' , '1856-12-28' ),
( 'Warren' , 'Harding' , '1865-11-02' ),
( 'Calvin' , 'Coolidge' , '1872-07-04' ),
( 'Herbert' , 'Hoover' , '1874-08-10' ),
( 'Franklin' , 'Roosevelt' , '1882-01-30' ),
( 'Harry' , 'Truman' , '1884-05-08' ),
( 'Dwight' , 'Eisenhower', '1890-10-14' ),
( 'John' , 'Kennedy' , '1917-05-29' ),
( 'Lyndon' , 'Johnson' , '1908-08-27' ),
( 'Richard' , 'Nixon' , '1913-01-09' ),
( 'Gerald' , 'Ford' , '1913-07-14' ),
( 'Jimmy' , 'Carter' , '1924-10-01' ),
( 'Ronald' , 'Reagan' , '1911-02-06' ),
( 'George' , 'Bush' , '1924-06-12' ),
( 'Bill' , 'Clinton' , '1946-08-19' ),
( 'George' , 'Bush' , '1946-07-06' ),
( 'Barack' , 'Obama' , '1961-08-04' ),
( 'Donald' , 'Trump' , '1946-06-14' )
}
# PART TWO : display the content of table Presidents in TkTreeCtrl
# Variables needed for paging the recordset, using LIMIT + OFFSET clauses :
# Remark : LIMIT + OFFSET use for recordset paging is an unefficient method on big recordset (choosed here for simplicity)
set ::_nbLigW 10 ;# nb of records, read as a whole, from SQlite and inserted in one chunk in a range of items of the TreeCtrl widget.
# A "page", materialization of this chunk, is identified by "pageW" variable
set ::pageW 0 ;# starts from page 0
# register the count of records present in table Presidents
set nbRecords [db1 eval "SELECT count(*) FROM Presidents"]
proc InitData {} {
# fill the treectrl with a subset of Presidents table
# traverse the current page of the recordset :
db1 eval "SELECT Country, FirstName, LastName, BirthDate
FROM Presidents
ORDER BY LastName, FirstName
LIMIT $::_nbLigW OFFSET $::pageW * $::_nbLigW" result {
set item [.t.frame.tree item create -parent root]
foreach col $result(*) {
.t.frame.tree item style set $item [.t.frame.tree column id $col] s1
.t.frame.tree item text $item [.t.frame.tree column id $col] $result($col)
}
}
}
# Create a toplevel treectrl
# toplevel
toplevel .t
wm protocol .t WM_DELETE_WINDOW {exit}
# treectrl + scrollbars
ttk::frame .t.frame
ttk::scrollbar .t.frame.sy -command [namespace code [list .t.frame.tree yview]] -orient vertical
ttk::scrollbar .t.frame.sx -command [namespace code [list .t.frame.tree xview]] -orient horizontal
treectrl .t.frame.tree -yscrollcommand [list .t.frame.sy set] \
-xscrollcommand [list .t.frame.sx set]
pack .t.frame.sy -side right -fill both
pack .t.frame.sx -side bottom -fill both
pack .t.frame.tree -side left -fill both -expand 1
pack .t.frame -side top -fill both -expand 1
# Create style
.t.frame.tree element create el1 text
.t.frame.tree style create s1
.t.frame.tree style elements s1 el1
.t.frame.tree style layout s1 el1 -iexpand nsew
# Create columns (Country, FirstName, LastName, BirthDate) :
foreach col [list Country FirstName LastName BirthDate] {
.t.frame.tree column create -text $col \
-tags $col
}
# Create treectrl' items with data loaded from table Presidents :
# -> call proc InitData
InitData
# buttons for navigation
ttk::frame .t.btns
# button "previous page"
ttk::button .t.btns.previous -text "previous page" \
-command {
# If already on the first page
if {$::pageW == 0} {break}
# Calculate the previous page
incr ::pageW -1
# Delete all existing items
.t.frame.tree item delete 1 [.t.frame.tree item lastchild root]
# Create new items for the new page
InitData
}
# button "next page"
ttk::button .t.btns.next -text "next page" \
-command {
# If already on the last page
if {$::_nbLigW * ($::pageW + 1) >= $nbRecords} {break}
# Calculate next page
incr ::pageW
# Delete all existing items
.t.frame.tree item delete 1 [.t.frame.tree item lastchild root]
# Create new items for the new page
InitData
}
pack .t.btns.next -side right -padx 10
pack .t.btns.previous -side right -padx 10
pack .t.btns -side bottom -pady 10
update
# Resize toplevel
wm geometry .t [winfo reqwidth .t]x[winfo reqheight .t]