sql.java

用JAVA实现的miniSQL

import java.io.*;
public class SQL {

    public SQL() {
    }
    
    public static void main(String[] args) throws Exception{
    	Interpreter interpreter = new Interpreter("quit;");
    	Catalog catalog = new Catalog();
    	BufferManager buffer = new BufferManager();
    	IndexManager index = new IndexManager(buffer);
    	RecordManager record = new RecordManager(buffer, index);
     	API api = new API(index, record, catalog);
    	String command = new String("");
    	System.out.print("SQL>");
    	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    	while(true){
    		String com= br.readLine();
    		while(com!=null){    	
    		    int pos=0;
    		    while(com!=null){
    			    pos = com.indexOf(";");
    			    if(pos>=0){
    				    command = command+"\n"+com.substring(0,pos+1);
    				    interpreter.init(command);
    				    if(catalog.test(interpreter)){
    				    	if(api.exec(interpreter))
    				    		System.out.println("execute successfully");
    				    	else{
    				    		System.out.println("execute failed");
    				    	}
    				    }
    				    else{
    				    	if(interpreter.mean == 0)
    				    		;
    				    	else
    				    	  System.out.println("出错啦，请确保各属性和表名正确");
    				    }
    				    System.out.print("SQL>");
    				    if(pos!=com.length()-1){
    					    command = com.substring(pos,com.length());
    				    }
    				    else 
    				    	command = new String("");
    				    break;
    			    }
    			    System.out.print("SQL>");
    			    command = command + "\n"+com;
    			    com = br.readLine();
    		    }
    	    	com = br.readLine();
    	    }
    	}
    }
}