Table creation
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You are encouraged to solve this task according to the task description, using any language you may know.
In this task, the goal is to create a table to exemplify most commonly used data types and options.
PostgreSQL
Postgres developers, please feel free to add additional data-types you commonly use to this example.
-- This is a comment CREATE SEQUENCE account_seq start 100; CREATE TABLE account ( account_id int4 PRIMARY KEY DEFAULT nextval('account_seq'), created date not null default now(), active bool not null default 't', username varchar(16) unique not null, balance float default 0, age int2, notes text ); CREATE TABLE account_note ( account_id int4 not null REFERENCES account, created timestamp not null default now(), note text not null, unique(account_id, note) ); -- bool: 't', 'f' or NULL -- int2: -32768 to +32767 -- int4: -2147483648 to +2147483647 -- float: decimal -- date: obvious -- timestamp: date time -- char(#): space padded text field with length of # -- varchar(#): variable length text field up to # -- text: not limited
Tcl
Tables, as used in relational databases, seem far away conceptually from Tcl. However, the following code demonstrates how a table (implemented as a list of lists, the first being the header line) can be type-checked and rendered: <lang Tcl>proc table_update {_tbl row args} {
upvar $_tbl tbl set heads [lindex $tbl 0] if {$row eq "end+1"} { lappend tbl [lrepeat [llength $heads] {}] set row [expr [llength $tbl]-1] } foreach {key val} $args { set col [lsearch $heads $key*] foreach {name type} [split [lindex $heads $col] |] break if {$type eq "float"} {set type double} if {$type eq "date"} { if [catch {clock scan $val}] { error "bad date value $val" } } elseif {$type ne ""} { if ![string is $type -strict $val] { error "bad $type value $val" } } lset tbl $row $col $val }
} proc table_format table {
set maxs {} foreach item [lindex $table 0] { set item [lindex [split $item |] 0] lappend maxs [string length $item] } foreach row [lrange $table 1 end] { set i 0 foreach item $row max $maxs { if {[string length $item]>$max} {lset maxs $i [string length $item]} incr i } } set head + foreach max $maxs {append head -[string repeat - $max]-+} set res $head\n foreach row $table { if {$row eq [lindex $table 0]} { regsub -all {\|[^ ]+} $row "" row } append res | foreach item $row max $maxs { append res [format " %-${max}s |" $item] } append res \n if {$row eq [lindex $table 0]} { append res $head \n } } append res $head
}
- ------------------------------------- Test and demo:
set mytbl [list [list \
account_id|int \ created|date \ active|bool \ username \ balance|float \ ]]
table_update mytbl end+1 \
account_id 12345 \ username "John Doe" \ balance 0.0 \ created 2009-05-13
table_update mytbl end+1 \
account_id 12346 \ username "Jane Miller" \ balance 0.0 \ created 2009-05-14
puts [table_format $mytbl]</lang> Output:
+------------+------------+--------+-------------+---------+ | account_id | created | active | username | balance | +------------+------------+--------+-------------+---------+ | 12345 | 2009-05-13 | | John Doe | 0.0 | | 12346 | 2009-05-14 | | Jane Miller | 0.0 | +------------+------------+--------+-------------+---------+