v/compiler/query.v

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// Copyright (c) 2019 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
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module main
import strings
// `db.select from User where id == 1 && nr_bookings > 0`
fn (p mut Parser) select_query(fn_ph int) string {
mut q := 'select '
p.check(.key_select)
n := p.check_name()
if n == 'count' {
q += 'count(*) from '
p.check_name()
}
table_name := p.check_name()
// Register this type's fields as variables so they can be used in where expressions
typ := p.table.find_type(table_name)
if typ.name == '' {
p.error('unknown type `$table_name`')
}
// 'select id, name, age from...'
if n == 'from' {
for i, field in typ.fields {
q += field.name
if i < typ.fields.len - 1 {
q += ', '
}
}
q += ' from '
}
for field in typ.fields {
//println('registering sql field var $field.name')
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p.cur_fn.register_var({ field | is_used:true })
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}
q += table_name
// `where` statement
if p.tok == .name && p.lit == 'where' {
p.next()
p.cgen.start_tmp()
p.is_sql = true
p.bool_expression()
p.is_sql = false
q += ' where ' + p.cgen.end_tmp()
}
// limit?
mut query_one := false
if p.tok == .name && p.lit == 'limit' {
p.next()
p.cgen.start_tmp()
p.is_sql = true
p.bool_expression()
p.is_sql = false
limit := p.cgen.end_tmp()
q += ' limit ' + limit
// `limit 1` means we are getting `User`, not `[]User`
if limit.trim_space() == '1' {
query_one = true
}
}
//println('sql query="$q"')
if n == 'count' {
p.cgen.set_placeholder(fn_ph, 'pg__DB_q_int(')
p.gen(', tos2("$q"))')
} else {
// Build an object, assign each field.
tmp := p.get_tmp()
mut obj_gen := strings.new_builder(100)
for i, field in typ.fields {
mut cast := ''
if field.typ == 'int' {
cast = 'string_int'
}
obj_gen.writeln('$tmp . $field.name = $cast( *(string*)array__get(row.vals, $i) );')
}
// One object
if query_one {
p.cgen.insert_before('
pg__Row row = pg__DB_exec_one(db, tos2("$q"));
$table_name $tmp;
${obj_gen.str()}
')
p.cgen.resetln(tmp)
}
// Array
else {
p.cgen.insert_before('
array_pg__Row rows = pg__DB_exec(db, tos2("$q"));
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//printf("ROWS LEN=%d\\n", rows.len);
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// TODO preallocate
array arr_$tmp = new_array(0, 0, sizeof($table_name));
for (int i = 0; i < rows.len; i++) {
pg__Row row = *(pg__Row*)array__get(rows, i);
$table_name $tmp;
${obj_gen.str()}
_PUSH(&arr_$tmp, $tmp, ${tmp}2, $table_name);
}
')
p.cgen.resetln('arr_$tmp')
}
}
if n == 'count' {
return 'int'
} else if query_one {
return table_name
} else {
p.register_array('array_$table_name')
return 'array_$table_name'
}
}
// `db.insert(user)`
fn (p mut Parser) insert_query(fn_ph int) {
p.check_name()
p.check(.lpar)
var_name := p.check_name()
p.check(.rpar)
var := p.cur_fn.find_var(var_name)
typ := p.table.find_type(var.typ)
table_name := var.typ
mut fields := '' // 'name, city, country'
mut params := '' // params[0] = 'bob'; params[1] = 'Vienna';
mut vals := '' // $1, $2, $3...
mut nr_vals := 0
for i, field in typ.fields {
if field.name == 'id' {
continue
}
fields += field.name
vals += '$' + i.str()
nr_vals++
params += 'params[${i-1}] = '
if field.typ == 'string' {
params += '$var_name . $field.name .str;\n'
} else if field.typ == 'int' {
params += 'int_str($var_name . $field.name).str;\n'
} else {
p.error('V ORM: unsupported type `$field.typ`')
}
if i < typ.fields.len - 1 {
fields += ', '
vals += ', '
}
}
p.cgen.insert_before('char* params[$nr_vals];' + params)
p.cgen.set_placeholder(fn_ph, 'PQexecParams( ')
p.genln('.conn, "insert into $table_name ($fields) values ($vals)", $nr_vals,
0, params, 0, 0, 0)')
}