⭐ 欢迎来到虫虫下载站! | 📦 资源下载 📁 资源专辑 ℹ️ 关于我们
⭐ 虫虫下载站

📄 tinysqlparser.java

📁 TinySQL是一个轻量级的纯java数据库引擎
💻 JAVA
📖 第 1 页 / 共 2 页
字号:
            if ( ft2.countFields() != 2 ) throwException(4);
            columnList.addElement(ft2.getField(0));
            contextList.addElement(inputKeyWord);
            valueList.addElement(UtilString.removeQuotes(ft2.getField(1)));
         } else if ( inputKeyWord.equals("WHERE") ) {
            whereClause = new tinySQLWhere(nextField,tables);
         } else if ( !inputKeyWord.equals("TABLE") ) {
            throwException(10);
         }
      }
      lastKeyWord = inputKeyWord;
   }
   public void validateTable(String tableSpec) throws tinySQLException
   {
      validateTable(tableSpec,false);
   }
   public void validateTable(String tableSpec,boolean closeTable) 
      throws tinySQLException
   {
/*
 *    Create a table object for each table used in the SELECT statement
 *    and store these objects in the tables Hashtable.  Save the original
 *    list of table names to set the default selection order.
 *
 *    If closeTable is true the table object will be closed after it is
 *    validated (for DROP TABLE and ALTER TABLE commands).
 */
      String tableName,tableAlias,tableNameAndAlias,sortName;
      tinySQLTable addTable,sortTable;
      boolean tableAdded;
      FieldTokenizer ftTable;
      int i,addRowCount,sortRowCount;
      ftTable = new FieldTokenizer(tableSpec,' ',false);
      tableName = ftTable.getField(0);
      tableAlias = (ftTable.getField(1,tableName)).toUpperCase();
      tableNameAndAlias = tableName + "->" + tableAlias;
      addTable = dbEngine.getTable(tableNameAndAlias);
      addTable.GoTop();
      addRowCount = addTable.GetRowCount();
      if ( closeTable ) addTable.close();
      if ( tinySQLGlobals.PARSER_DEBUG )
         System.out.println("Add table " + tableNameAndAlias + " to tables");
      tables.put(tableNameAndAlias,addTable);
      tableAdded = false;
      for (i = 0; i < tableList.size(); i++)
      {
         sortName = (String)tableList.elementAt(i);
         sortTable = (tinySQLTable)tables.get(sortName);
         sortRowCount = sortTable.GetRowCount();
/*
 *       Sort the table selections from smallest to largest table to 
 *       enhance the query performance.
 */
         if ( addRowCount > sortRowCount ) continue;
         tableList.insertElementAt(tableNameAndAlias,i);
         tableAdded = true;
         break;
      }
      if ( !tableAdded ) tableList.addElement(tableNameAndAlias);
      if ( tinySQLGlobals.PARSER_DEBUG ) 
      {
         System.out.println("Table selection order");
         for ( i = 0; i < tableList.size(); i++ )
         {
            sortName = (String)tableList.elementAt(i);
            sortTable = (tinySQLTable)tables.get(sortName);
            sortRowCount = sortTable.GetRowCount();
            System.out.println(sortName + " " + sortRowCount);
         }
      }
   }
/*
 * Validate the column specifications by checking against the tables.
 */
   public void validateColumns() throws tinySQLException
   {
      String columnName,columnAlias,columnContext;
      tsColumn columnObject;
      boolean selectStar;
      tinySQLTable jtbl;
      int i,j;
/*
 *    Check for a column named *
 */
      selectStar = false;
      for (i = 0; i < columnList.size(); i++)
      {
         columnName = (String)columnList.elementAt(i);
         columnContext = (String)contextList.elementAt(i);
         if ( columnName.equals("*") )
         {
            if ( !columnContext.equals("SELECT") )
               throw new tinySQLException("* must be a SELECT column.");
            selectStar = true;
            break;
         }
      }
      if ( selectStar) 
      {
/*
 *       A column * has been found.  Delete the existing list of SELECT
 *       columns and replace by using an enumeration variable to cycle through 
 *       the columns in the tables Hashtable.
 */
         for ( i = 0; i < columnList.size(); i++ )
         {
            columnContext = (String)contextList.elementAt(i);
            if ( columnContext.equals("SELECT") )
            {
               columnList.removeElementAt(i);
               contextList.removeElementAt(i);
               columnAliasList.removeElementAt(i);
            }
         }
         for ( i = 0; i < tableList.size(); i++ )
         {
            jtbl = (tinySQLTable)tables.get((String)tableList.elementAt(i));
/*
 *          Expand to all columns.
 */
            for ( j = 0; j < jtbl.columnNameKeys.size(); j++ )
            {
               columnName = (String)jtbl.columnNameKeys.elementAt(j);
               columnList.addElement(jtbl.table + "->" + jtbl.tableAlias
                        + "." + columnName);
               columnAliasList.addElement(columnName);
               contextList.addElement("SELECT");
            }
         }
      }
/*
 *    Build a column object for each selected column.
 */
      if ( tables == (Hashtable)null )
         System.out.println("*****Column validation - no tables defined.");
      for (i = 0; i < columnList.size(); i++)
      {
         columnName = (String)columnList.elementAt(i);
         columnContext = (String)contextList.elementAt(i);
         columnAlias = (String)null;
         if ( i < columnAliasList.size() )
            columnAlias = (String)columnAliasList.elementAt(i);
         columnObject = new tsColumn(columnName,tables,columnContext);
         columnObject.alias = UtilString.removeQuotes(columnAlias);
         columns.addElement(columnObject);
      }
   }
/*
 * Parse out the column definition for a CREATE statement.
 */
   public tsColumn parseColumnDefn(String columnDefn) throws tinySQLException
   {
      tsColumn createColumn;
      int i;
      FieldTokenizer ft;
      String columnName,fieldString,tempString,colTypeStr,colTypeSpec;
      ft = new FieldTokenizer(columnDefn.toUpperCase(),' ',false);
/*
 *    A column definition must consist of a column name followed by a 
 *    column specification.
 */
      if ( ft.countFields() < 2 ) throwException(2);
      columnName = ft.getField(0);
/*
 *    Check for quotes around a column name that may contain blanks.
 */
      if ( columnName.charAt(0) == '"' &
           columnName.charAt(columnName.length() - 1) == '"' )
         columnName = columnName.substring(1,columnName.length() - 1);
      if ( columnName.length() > 11 )
      {
         columnName = tinySQLGlobals.getShortName(columnName);
      }
      createColumn = new tsColumn(columnName);
      colTypeStr = "";
      for ( i = 1; i < ft.countFields(); i++ )
         colTypeStr += ft.getField(1);
      ft = new FieldTokenizer(colTypeStr,'(',false);
      colTypeStr = ft.getField(0);
      createColumn.size = 10;
      createColumn.decimalPlaces = 0;
      if ( colTypeStr.equals("FLOAT") ) 
      {
         createColumn.size = 12;
         createColumn.decimalPlaces = 2;
      }
      colTypeSpec = ft.getField(1);
      if ( !colTypeSpec.equals("NULL") )
      {
/*
 *       Parse out the scale and precision if supplied.
 */
         ft = new FieldTokenizer(colTypeSpec,',',false);
         createColumn.size = ft.getInt(0,8);
         createColumn.decimalPlaces = ft.getInt(1,0);
      }
      createColumn.type = Integer.MIN_VALUE;
      for ( i = 0; i < colTypeNames.length; i++ )
         if ( colTypeStr.equals(colTypeNames[i]) )
             createColumn.type = colTypes[i]; 
      if ( createColumn.type == Integer.MIN_VALUE ) throwException(8);
      if ( tinySQLGlobals.PARSER_DEBUG )
         System.out.println("Column " + createColumn.name 
         + ", type is " + createColumn.type + ",size is " + createColumn.size 
         + ",precision is " + createColumn.decimalPlaces);
      return createColumn;
   }
/*
 * This method is used to identify SQL key words, and the order in which they
 * should appear in the SQL statement.
 */
   public int getKeywordIndex(String inputContext,String inputWord)
   {
      String[][] sqlSyntax = {{"SELECT","FROM","WHERE","GROUP","ORDER","BY"},
        {"INSERT","INTO","VALUES"},
        {"DROP","TABLE"},
        {"DELETE","FROM","WHERE"},
        {"CREATE","TABLE"},
        {"UPDATE","SET","WHERE"},
        {"ALTER","TABLE","DROP","MODIFY","ADD","RENAME"}};
      int i,j;
      for ( i = 0; i < sqlSyntax.length; i++ )
      {
         for ( j = 0; j < sqlSyntax[i].length; j++ )
         {
            if ( sqlSyntax[i][0].equals(inputContext) &
                 sqlSyntax[i][j].equals(inputWord) )
               return j;
         }
      }
      return Integer.MIN_VALUE;
   }
/*
 * Add an action Hashtable to the list of actions
 */
   public void addAction () throws tinySQLException, CloneNotSupportedException
   {
      int i,columnCount;
      tsColumn checkColumn,orderColumn;
      Hashtable newAction =  new Hashtable();
      newAction.put("TYPE", statementType);
      if ( statementType.equals("SELECT") )
      {
         newAction.put("TABLES",tables);
         if ( whereClause != (tinySQLWhere)null )
            newAction.put("WHERE",whereClause);
/*
 *       Validate the column specifications and expand * if present
 */
         validateColumns();
/*
 *       If no ORDER BY clause was specified, default to the list of
 *       SELECT columns.
 */
         if ( defaultOrderBy ) 
         {
            columnCount = columns.size();
            for ( i = 0; i < columnCount; i++ ) 
            {
               orderColumn = (tsColumn)(columns.elementAt(i));
               if ( orderColumn.getContext("SELECT") )
               {
                  orderColumn.addContext("ORDER");
               }
            }
         }
         newAction.put("COLUMNS",columns);
         if ( orderType != (String)null ) newAction.put("ORDER_TYPE",orderType);
         if ( distinct ) newAction.put("DISTINCT","TRUE");
      } else if ( statementType.equals("DROP_TABLE") ) {
         newAction.put("TABLE",tableName);
      } else if ( statementType.equals("CREATE_TABLE") ) {
         newAction.put("TABLE",tableName);
         newAction.put("COLUMN_DEF",columnList);
      } else if ( statementType.equals("ALTER_RENAME") ) {
         newAction.put("TABLE",tableName);
         newAction.put("OLD_COLUMN",oldColumnName);
         newAction.put("NEW_COLUMN",newColumnName);
      } else if ( statementType.equals("ALTER_ADD") ) {
         newAction.put("TABLE",tableName);
         newAction.put("COLUMN_DEF",columnList);
      } else if ( statementType.equals("ALTER_DROP") ) {
         newAction.put("TABLE",tableName);
         newAction.put("COLUMNS",columnList);
      } else if ( statementType.equals("DELETE") ) {
         newAction.put("TABLE",tableName);
         if ( whereClause != (tinySQLWhere)null )
            newAction.put("WHERE",whereClause);
      } else if ( statementType.equals("INSERT") |
                  statementType.equals("UPDATE") ) {
         newAction.put("TABLE",tableName);
         if ( columnList.size() != valueList.size() ) throwException(5);
         newAction.put("COLUMNS",columnList);
         newAction.put("VALUES",valueList);
         if ( whereClause != (tinySQLWhere)null )
            newAction.put("WHERE",whereClause);
      }
      actionList.addElement(newAction);
   }
   public void throwException(int exceptionNumber) throws tinySQLException
   {
      throwException(exceptionNumber,(String)null);
   }
   public void throwException(int exceptionNumber, String parameter)
      throws tinySQLException
   {
      String exMsg = (String)null;
      if ( exceptionNumber == 1 )
         exMsg = "CREATE TABLE must be followed by a table name and a list"
         + " of column specifications enclosed in brackets.";
      else if ( exceptionNumber == 2 )
         exMsg = "A column specification must consist of a column name"
         + " followed by a column type specification.";
      else if ( exceptionNumber == 3 )
         exMsg = "INTO should be followed by a table name and "
         + "a list of columns enclosed in backets.";
      else if ( exceptionNumber == 4 )
         exMsg = "SET must be followed by assignments in the form"
         + " <columnName>=<value>.";
      else if ( exceptionNumber == 5 )
         exMsg = "INSERT statement number of columns and values provided"
         + " do not match.";
      else if ( exceptionNumber == 6 )
         exMsg = "BY cannot be the first keyword.";
      else if ( exceptionNumber == 7 )
         exMsg = "ORDER BY can only be followed by the ASC or DESC directives";
      else if ( exceptionNumber == 8 )
         exMsg = "Supported column types are INT,CHAR,FLOAT,DATE";
      else if ( exceptionNumber == 9 )
         exMsg = "Expecting SELECT, INSERT, ALTER, etc. in " + statementType;
      else if ( exceptionNumber == 10 )
         exMsg = "Unrecognized keyword ";
      throw new tinySQLException(exMsg);
   }
   public Vector getActions()
   {
      return actionList;
   }
}

⌨️ 快捷键说明

复制代码 Ctrl + C
搜索代码 Ctrl + F
全屏模式 F11
切换主题 Ctrl + Shift + D
显示快捷键 ?
增大字号 Ctrl + =
减小字号 Ctrl + -