Make an SQL interpreter by yourself

In some small applications, you do not need to use large database software. You can use the database to manage your own SQL interpreter. This interpreter can explain commonly used SQL commands. You can add other functions on your own. & Lt ;? Php (as the mainstream development language) classDB_SyntaxHighlighter makes an SQL interpreter
In some small applications, there is no need to use large database software. You can use the database to manage your own SQL interpreter.
This interpreter can explain commonly used SQL commands. You can add other functions on your own.

Class DB_text {
Var $ conn;
Var $ classname = "db_text ";
Var $ database;
Function on_create (){
}
Function connect ($ database_name ){
$ This-> database = $ database_name;
If (! File_exists ($ database_name )){
$ This-> conn = array ();
$ This-> _ close ();
}
$ Fp = fopen ($ this-> database, "r ");
$ This-> conn = unserialize (fread ($ fp, filesize ($ this-> database )));
Fclose ($ fp );
}
Function & query ($ query ){
If (eregi ("select", $ query) return $ this-> _ select ($ query );
If (eregi ("insert", $ query) return $ this-> _ insert ($ query );
If (eregi ("delete", $ query) return $ this-> _ delete ($ query );
If (eregi ("update", $ query) return $ this-> _ update ($ query );
Return array ();
}
Function fetch_row (& $ result ){
If (list ($ key, $ value) = each ($ result ))
Return $ value;
Return false;
}
Function num_rows ($ result ){
Return count ($ result );
}

/**
* Auxiliary query functions
*/
Function _ select ($ query ){
If (eregi ("(order by (. +)", $ query, $ regs )){
$ Order = $ regs [2];
$ Query = eregi_replace ($ regs [1], "", $ query );
}
If (eregi ("(group by (. +)", $ query, $ regs )){
$ Group = $ regs [2];
$ Query = eregi_replace ($ regs [1], "", $ query );
}
Eregi ("select. * from ([0-9a-z _] +) * (where + (. + ))? ", $ Query, $ regs );
If ($ regs [3]! = ""){
$ Keys = $ this-> _ where ($ regs [3], "$ this-> conn [$ regs [1]");
While (list ($ key, $ value) = each ($ keys )){
$ Rs [] = $ this-> conn [$ regs [1] [$ value];
}
} Else {
$ Rs = $ this-> conn [$ regs [1];
}
If ($ order ){
Sscanf ($ order, "% s", $ key, $ type );
If (empty ($ type) $ type = "asc ";
$ This-> _ sort ($ rs, $ key, $ type );
}
Return $ rs;
}