sqlite: Functions thats returns the values resulting from a 'SELECT' query and name of column - Feature ISSUE #20565

vlib/db/sqlite/sqlite.c.v

@@ -1,5 +1,7 @@
 module sqlite
 
+import regex { regex_opt }
+
 $if freebsd || openbsd {
  #flag -I/usr/local/include
  #flag -L/usr/local/lib
@@ -85,6 +87,11 @@ pub mut:
  vals []string
 }
 
+pub struct QuerySet {
+pub mut:
+ vals map[string]string
+}
+
 //
 fn C.sqlite3_open(&char, &&C.sqlite3) int
 
@@ -248,6 +255,101 @@ pub fn (db &DB) exec(query string) ![]Row {
  return rows
 }
 
+// get_queryset returns the values resulting from a 'SELECT' query and the name of each column. If an alias is provided either through the 'as' command or not, the returned value becomes the alias.
+@[manualfree]
+pub fn (db &DB) get_queryset(query string) ![]QuerySet {
+ query_lower := query.to_lower()
+
+ // 'select' syntax verified on: https://www.sqlite.org/lang_select.html and
+ // https://www.sqlite.org/syntax/join-clause.html
+ mut select_header := regex_opt(r'select((\s)+(all)|(distinct)(\s)+)|(\s)+')!
+ mut from := regex_opt(r'(\s)+from(\s)+')!
+
+ // or do not include 'FROM', just like 'SELECT 1 + 1'
+ if query_lower.count('select') == 1 && query_lower.contains('from') {
+ // The execution of this function indicates that the passed
+ // query is syntactically correct, which is why no additional verification
+ rows := db.exec(query)!
+
+ defer {
+ unsafe { rows.free() }
+ }
+
+ if rows.len == 0 {
+ return []QuerySet{}
+ } else {
+ // Finding final index of select((\s)+(all)|(distinct)(\s)+)|(\s)+ inside query_lower string
+ _, end_select := select_header.match_string(query_lower)
+
+ // Finding initial and final index of (\s)+from(\s)+ inside query_lower string
+ init_from, end_from := from.find(query_lower)
+
+ // Get fields possibly separated by ',' like: select field_1, field_2 as f2, from table_name
+ fields := query.substr(end_select, init_from).split(',')
+
+ mut query_set := []QuerySet{}
+ mut tuple := map[string]string{}
+
+ if fields[0] == '*' {
+ table_name := query.substr(end_from, query.len).replace(';', '').split(' ')[0]
+
+ // Get all fields
+ all_columns_name := db.exec('pragma table_info(${table_name})')!
+
+ defer {
+ unsafe { all_columns_name.free() }
+ }
+
+ mut i := 0
+
+ for row in rows {
+ for i < row.vals.len {
+ // position 1 has a database column attribute
+ tuple[all_columns_name[i].vals[1]] = row.vals[i]
+ i++
+ }
+ i = 0
+
+ query_set << QuerySet{tuple}
+ tuple = map[string]string{}
+ }
+ } else {
+ mut i := 0
+
+ for row in rows {
+ for field in fields {
+ // verifying formats like:
+ // select column_1 as alias_column_1 from table_name -> alias creation with 'as'
+ // select column_1 alias_column_1 from table_name -> alias creationg without 'as'
+ // select column_1 from table_name -> with alias being column_1
+ all_field_alias := if field.contains('as') {
+ field.split('as')
+ } else {
+ field.split(' ')
+ }
+
+ alias := all_field_alias[all_field_alias.len - 1].replace(' ',
+ '')
+ tuple[alias] = row.vals[i]
+ i++
+ }
+
+ i = 0
+ query_set << QuerySet{tuple}
+ tuple = map[string]string{}
+ }
+ }
+
+ return query_set
+ }
+ } else {
+ return &SQLError{
+ msg: 'This is not a selection query or contains subqueries'
+ code: sqlite.sqlite_done
+ }
+ }
+}
+
 // exec_one executes a query on the given `db`.
 // It returns either the first row from the result, if the query was successful, or an error.
 @[manualfree]

vlib/db/sqlite/sqlite_test.v

@@ -61,7 +61,7 @@ fn test_sqlite() {
  assert users.len == 4
  code := db.exec_none('vacuum')
  assert code == 101
- user := db.exec_one('select * from users where id = 3') or { panic(err) }
+ user := db.exec_one('select * from users where id = 3')!
  println(user)
  assert user.vals.len == 2
 
@@ -79,7 +79,73 @@ fn test_sqlite() {
  db.exec("delete from users where name='Sam'")!
  assert db.get_affected_rows_count() == 1
 
- db.close() or { panic(err) }
+ db.get_queryset('SELECT * FROM users')!
+ assert db.get_affected_rows_count() == 1
+
+ db.get_queryset('Select * From users')!
+ assert db.get_affected_rows_count() == 1
+
+ db.get_queryset('select * from users')!
+ assert db.get_affected_rows_count() == 1
+
+ db.get_queryset('SELECT * FROM users')!
+ assert db.get_affected_rows_count() == 1
+
+ db.get_queryset('Select * From users')!
+ assert db.get_affected_rows_count() == 1
+
+ db.get_queryset('select * from users')!
+ // assert db.get_affected_rows_count() == 1
+
+ db.get_queryset('SELECT name, id FROM users WHERE id = 3')!
+ assert db.get_affected_rows_count() == 1
+
+ db.get_queryset('Select name as n From users WHERE id = 3')!
+ assert db.get_affected_rows_count() == 1
+
+ db.get_queryset('select name n from users WHERE id = 3')!
+ assert db.get_affected_rows_count() == 1
+
+ db.get_queryset('SELECT name, id FROM users WHERE id = 3')!
+ assert db.get_affected_rows_count() == 1
+
+ db.get_queryset('Select name as name From users WHERE id = 3')!
+ assert db.get_affected_rows_count() == 1
+
+ db.get_queryset('select name n from users WHERE id = 3')!
+ assert db.get_affected_rows_count() == 1
+
+ db.get_queryset('SELECT * FROM users WHERE id = 3')!
+ assert db.get_affected_rows_count() == 1
+
+ db.get_queryset('select id from users WHERE id = 3')!
+ assert db.get_affected_rows_count() == 1
+
+ db.get_queryset('select id as i, name as n from users WHERE id = 3')!
+ assert db.get_affected_rows_count() == 1
+
+ db.get_queryset('select id _id, name _n from users WHERE id = 3')!
+ assert db.get_affected_rows_count() == 1
+
+ db.get_queryset('select max(id), name from users WHERE id = 3')!
+ assert db.get_affected_rows_count() == 1
+
+ db.get_queryset('select max(id) as max, name from users WHERE id = 3')!
+ assert db.get_affected_rows_count() == 1
+
+ db.get_queryset('select max(id) from users WHERE id = 3')!
+ assert db.get_affected_rows_count() == 1
+
+ db.get_queryset('select max(id) max, name n from users WHERE id = 3')!
+ assert db.get_affected_rows_count() == 1
+
+ db.get_queryset('select * from users;')!
+ assert db.get_affected_rows_count() == 1
+
+ db.get_queryset('select * from users ;')!
+ assert db.get_affected_rows_count() == 1
+
+ db.close()!
  assert !db.is_open
 }