NAME

SQL::Steno - Short hand for SQL and compact output

SYNOPSIS

Type some short-hand, see the corresponding SQL and its output:

 steno> TABLE1;somecolumn > 2    -- ; after tables means where
 select * from TABLE1 where somecolumn > 2;
 prepare: 0.000s   execute: 0.073s   rows: 14
   id|column1                                    |column2
     |                                           |    |column3
     |                                           |    | |somecolumn
 ----|-------------------------------------------|----|-|-|
   27|foo                                        |    |a|7|
   49|bar                                        |abcd|a|3|
   81|baz\nbazinga\nbazurka                      |jk  |b|9|
 1984|bla bla bla bla bla bla bla bla bla bla bla|xyz |c|5|
 ...
 steno> /abc|foo/#TBL1;.socol > 2    -- /regexp/ grep, #tableabbrev, .columnabbrev
 select * from TABLE1 where somecolumn > 2;
 prepare: 0.000s   execute: 0.039s   rows: 14
 id|column1
   |   |column2
   |   |    |[column3=a]
   |   |    |somecolumn
 --|---|----|-|
 27|foo|    |7|
 49|bar|abcd|3|
 steno> .c1,.c2,.some;#TE1#:ob2d3    -- ; before tables means from, 2nd # alias, :macro
 select column1,column2,somecolumn from TABLE1 TE1 order by 2 desc, 3;
 ...
 steno> n(), yr(), cw(,1,2,3)    -- functionabbrev before (, can have initial default arg
 select count(*), year(now()), concat_ws(',',1,2,3);
 ...
 steno> .col1,.clm2,.sn;#TBL1:jTBL2 u(id);mydate :b :m+3d and :d-w    -- :jTABLEABBREV and :+/- family
 select column1,column2,somecolumn from TABLE1 join TABLE2 using(id) where mydate
 between date_format(now(),"%Y-%m-01")+interval 3 day and curdate()-interval 1 week;
 ...

DESCRIPTION

You're the command-line type, but are tired of typing select * from TABLE where CONDITION, always forgetting the final ;? Output always seems far too wide and at least mysql cli messes up the format when it includes newlines?

This module consists of the function convert which implements a configurable ultra-compact language that maps to SQL. Then there is run which performs normal SQL queries but has various tricks for narrowing the output. It can also grep on whole rows, rather than having to list all fields that you expect to match. They get combined by the function shell which converts and runs in an endless loop.

This is work in progress, only recently isolated from a monolithic script. Language elements and API may change as the need arises, e.g. :macro used to be @macro, till the day I wanted to use an SQL-variable and noticed the collision. In this early stage, you are more than welcome to propose ammendments, especially if they make the language more powerful and/or more consistent. Defaults are for MariaDB/MySQL, though the mechanism also works with other DBs.

convert

This function takes a short-hand query in $_ and transforms it to SQL. See "shell" for more run time oriented features.

:\namespec(strings)   or   :\namespec%join(strings)

This is a special macro that transforms odd lists to SQL syntax. It takes a list of unquoted strings and quotes each one of them in various ways. The syntax is inspired by the Shell single character quote and Perl's \(...) syntax. The namespec is a combination of an optional name (set up with the Perl function Quote), followed by an optional spec that extends the named spec. The strings can get split on a variety of one or even simultaneously various characters, which you can give in any order in the spec:

\ (backslash)

This one isn't a character to split on, but rather prevents trimming the whitespace of both ends of the resulting strings.

, (comma), the default

You only need to specify it, if you want to split on commas, as well as other characters, at the same time. Where the \ (backslash) syntax is also used, when given a list, there is no default splitting of list members: :\{Perl code} and canned query's $\* & $\>. In that case you must specify it, if needed, e.g. $\,*.

  (space)

This one stands for any single whitespace. Since strings are normally trimmed, it's the equivalent of what the Shell does. But, if you combine it with \, which prevents trimming, you will get an empty string between each of multiple whitespaces.

- (minus)
: (colon)
; (semicolon)
. (period)
/ (slash)

The spec can also contain several of these characters to prevent certain strings from being quoted:

# (hash)

All numbers, including signed, floats, binary and hexadecimal stay literal. If you use - as a separator, there can be no negative numbers.

? (question mark)

The boolean values true and false stay literal.

ω (omega)   or   ^ (caret)

The value null stays literal. Note that ω is also a word character, that would be part of a name at the beginning of namespec. It is only the null-symbol following some non-word character, e.g. , (comma).

@ (at sign)

Variables @name stay literal.

! (exclamation mark)

Everything, presumed valid sql syntax, stays literal.

And you can give at most one spec for the quotes to use:

' (quote), the default
" (double quote)
` (backquote)
[] (brackets)
{} (braces)

In the latter two cases, the closing quotes are optional, for decoration only, or if code completion adds them.

The results are joined by comma, unless join is given. E.g. :\(a,b, c,NULL,true,-1.2) gives 'a','b','c','NULL','true','-1.2', while :\:"/\#?0(a:b/ c:NULL:true/-1.2) gives "a","b"," c",NULL,true,-1.2 and :\ !%&&(a b  c) gives a&&b&&c.

:macro

These are mostly simple text-replacements stored in %Macros. Unlike :\ these do not take arguments. There are also some dynamic macros. Those starting with :j (join) or :lj (left join) may continue into a table spec without the leading #. E.g. :ljtbl#t might expand to left join table t.

Those starting with :gb (group by) or :ob (order by) may be followed by result columns numbers from 1-9, each optionally followed by a or d for asc or desc. E.g. :ob2d3 gives order by 2 desc, 3.

:+interval   or   :time+interval   or   :-interval   or   :time-interval

These are time calculation macros, where an optional leading letter indicates a base time, and an optional trailing letter with an optional count means the offset. The letters are:

y

(this) year(start). E.g. :y+2m is march this year.

q

(this) quarter(start). E.g. :q+0 is this quarter, :q+q is next quarter.

m

(this) month(start). E.g. :-3m is whatever precedes, minus 3 months.

w

(this) week(start). E.g. :w+3d is this week thursday (or wednesday if you set $weekstart to not follow ISO 8601 and the bible).

d

(this) day(start). E.g. :d-w is midnight one week ago.

h

(this) hour(start). E.g. :h+30M is half past current hour.

M

(this) minute(start). E.g. :+10M is whatever precedes, plus 10min.

s

(this) second. E.g. :s-2h is exactly 2h ago.

:{Perl code}   or   :\namespec{Perl code}   or   :\namespec%join{Perl code}

This gets replaced by what it returns in list context. Undefined elements get rendered as NULL and they all get joined by join or else , (comma). They can become quoted like :\. Since the result is already a list, the elements don't get split by default. If you want that, you must specify it as in :\,{Perl code}.

#tbl   or   #tbl#   or   #tbl#alias

Here tbl is a key of %Tables or any abbreviation of known tables in @Tables. If followed by #, the abbreviation is used as an alias, unless an alias directly follows, in which case that is used.

.col   or   .col.   or   .col.alias

Here col is a key of %Columns or any abbreviation of columns of any table recognized in the query. If followed by ., the abbreviation is used as an alias, unless an alias directly follows, in which case that is used. It tries to be clever about whether the 1st . needs to be preserved, i.e. following a table name.

func(   or   func\namespec(strings)   or   func\namespec%join(strings)

Here func is a key of %Functions or any abbreviation of known functions in @Functions, which includes words typically followed by an opening parenthesis, such as u( for using(. i( becomes in(, whereas in( becomes ifnull(.

If the 2nd or 3rd form is used, the strings inside of the parentheses are treated just like :\namespec(strings), but in this case preserving the parentheses.

If the 1st argument of a function is empty and the abbrev or function is found in %DefaultArguments the value becomes the 1st argument. E.g. cw(,'a','b','c') or cw(,:\(a,b,c)) both become concat_ws(',','a','b','c').

Abbreviated Keyword

Finally it picks on the structure of the statement: These keywords can be abbreviated: se(lect), ins(ert), upd(ate) or del(ete). If none of these or set is present, select is assumed as default (more keywords need to be recognized in the future).

For select, semicolons are alternately replaced by from (the 1st being optional if it starts with a table name) and where. If no result columns are given, they default to *, see "SYNOPSIS". For update, semicolons are frst replaced by set and then where.

shell

This function reads, converts and (if $dbh is set) runs in an end-less loop (i.e. till end of file or ^D). Reading is a single line affair, unless you request otherwise. This can happen either, as in Unix Shell, by using continuation lines as long as you put a backslash at the end of your lines. Or there is a special case, if the 1st line starts with \\, then everything up to \\ at the end of one of the next lines, constitutes one entry.

In addition to converting, it offers a few extra features, performed in this order (i.e. &xyz can return /regexp/=literal sql etc.):

&{Perl code} following text

Run Perl code. It sees the optional following text in $_ and may modify it. If it returns undef, this statement is skipped. If it returns a DBI statement handle, run that instead of this statement. Else replace with what it returns.

Reprocess result as a shell entry (i.e. it may return another &query).

&query arg; ...   or   &query( arg; ... ) following text

These allow canned entries and are more complex than macros, in that they take arguments and replacement can depend on the argument.

Reprocess result as a shell entry (i.e. it may return another &query).

You can define your own canned queries with:

&{ Query name => 'doc', 'query' }

Here query becomes the replacement string for &name. It may contain arguments a bit like the Shell: $0 (name), $* (all arguments), $1, $2, ..., $10, ... (individual arguments) and $> (all arguments not adressed individually). They can become quoted like :\ as $\namespecarg or $\namespec%joinarg. Here arg is *, > or a number directly tacked on to spec or join. E.g.: $\-"1 splits the 1st (semi-colon separated from the 2nd) argument itself on - (minus), quotes the pieces with " (double quote) and joins them with , (comma). The two list variables $\* & $\> don't get split individually unless explicitly specified, e.g. $\,*. Putting the quotes inside the argument like this, eliminates them, if no argument is given.

/regexp/ statement   or   /regexp/i statement   or   !/regexp/ statement   or   !/regexp/i statement

This will treat the statement normally, but will join each output row into a ~ (tilde) separated string for matching. NULL fields are rendered as that string. E.g. to return only rows starting with a number 1-5, followed by a NULL field, you could write: /^[1-5]~NULL~/.

With a suffix i, matching becomes case insensitive. This is why the mostly optional space before statement is shown above. Without an i, but if the statement starts with the word i (e.g. your first column name), you must separate it with a space. With an i, if the statement starts with an alphanumeric caracter, you must separate it with a space.

Only matching rows are considered unless there is a preceding ! (exclamation mark), in which case only non-matching rows are considered.

You can provide your own formatting of the row by setting $regexp_fail to a Perl sub that returns a Perl expression as a string. That expression takes the row in @_ and shall be true if the row fails to match.

Caveat: the whole result set of the statement gets generated and transferred to the client. This is definitely much more expensive than doing the equivalent filtering in the where clause. But it is not a big deal for tens or maybe hundreds of thousands or rows, probably still faster than writing the corresponding SQL. And Perl's regexps are so much more powerful.

{Perl code}statement

Call Perl code for every output row returned by the statement with the array of column names as zeroth argument and the values after that (i.e. numbered from 1 like in SQL). It may modify individual values. If it returns false, the row is skipped.

You may combine /regexp/{Perl code} in any order and as many of them as you want.

The same caveat as for regexps applies here. But again Perl is far more powerful than any SQL functions.

=literal sql

A preceding = prevents conversion, useful for hitherto untreated keywords or where the conversion doesn't play well with your intention.

?

Help prefix. Alone it will give an overview. You can follow up with any of the special syntaxes, with or without an abbreviation. E.g. ?( will show all function abbreviations, whereas ?abbrev( will show only those functions matching abbrev or ?#abbrev only those tables matching abbrev.

??statement

Will convert and show, but not perform statement. If $dbh is not set, this is the default behaviour.

!System Shell code

Run System Shell code.

>filename   or   >>filename

Redirect or append next statement's output to filename. For known suffixes and options, see the next section.

|System Shell code

Pipe next statement's output through System Shell code.

Output Formats

The output format for the next SQL statement that is run, is chosen from the suffix of a redirection or a special suffix query. In both cases comma-separated options may be passed:

>filename.suffix
>filename.suffix( opt; ... )
>>filename.suffix
>>filename.suffix( opt; ... )
&.suffix opt; ...
&.suffix( opt; ... ) following text

The known suffixes and their respective options are:

.csv

This writes Comma Separated Values with one subtle trick: NULL and empty strings are distinguished by quoting the latter. Some tools like Perl's file DB DBD::CSV or rather its underlying Text::CSV_XS can pick that up. CSV can take one of these options:

semi

Use a semicolon as a separator. This is a common format in environments where the comma is the decimal separator. However if you want decimal commas, you must provide such formatting yourself.

tab

Use tabulators as column separators. Apart from that you get the full CSV formatting, so this is not the primitive .tsv format some tools may have.

.table

This is the default table format. But you need to name it, if you want to set options.

all

This is a shorthand for outputting everything in the long form, equivalent to ( NULL, crlf, date ).

crlf

Do not shorten \r\n to \R.

date

Output ISO dates fully instead of shortening 0000-00-00 to 0000- and yyyy-01-01 to yyyy- or yyyy-mm-01 to yyyy-mm-.

time

Output times fully instead of shortening 23:59(:59) to 24: and hh:00(:00) to hh: or hh:mm(:00) to hh:mm.

NULL
null

Output this keyword instead of the shorter ω from DB theory (or whatever you assigned to $NULL).

.yaml
.yml

Format output as YAML. This format has no options. Because its every value on a new line format can be more readable, there is a shorthand query &- for it.

YOUR SCRIPT

    package SQL::Steno;         # doesn't export yet, so get the functions easily
    use SQL::Steno;
    use DBI;
    our $dbh = DBI->connect( ... ); # preferably mysql, but other DBs should work (with limitations).
    # If you want #tbl and .col to work, (only) one of:
    init_from_query;            # fast, defaults to mysql information_schema, for which you need read permission
    init;                       # slow, using DBI dbh methods.
    # Set any of the variables mentioned above to get you favourite abbreviations.
    shell;

LICENSE

This program is free software; you may redistribute it and/or modify it under the same terms as Perl itself.

SEE ALSO

DBI, SQL::Interp, SQL::Preproc, SQL::Yapp, Jade

AUTHOR

(C) 2015, 2016 by Daniel Pfeiffer <occitan@esperanto.org>.