public override void EnterFrom(SelectSQLParser.FromContext context)
{
var table = context.table();
var tableLockType = context.tableLockType();
if (table == null || table.IsEmpty)
throw new MissingTableNameException();
var tableName = table.GetText();
if (string.IsNullOrEmpty(tableName))
throw new MissingTableNameException();
TableReadType readType = TableReadType.NONE;
if (tableLockType != null && !tableLockType.IsEmpty)
{
var nolockOption = tableLockType.NOLOCK();
var readpastOption = tableLockType.READPAST();
if (nolockOption != null)
readType = TableReadType.NOLOCK;
else if (readpastOption != null)
readType = TableReadType.READPAST;
}
this.SelectStmt.TableDescriptor = new TableDescriptor() { TableName = tableName, TableReadType = readType };
}
public static SelectStmtInfo ParseSQL(string sql)
{
Antlr4.Runtime.AntlrInputStream input = new Antlr4.Runtime.AntlrInputStream(sql);
SelectSQLLexer lexer = new SelectSQLLexer(input);
Antlr4.Runtime.UnbufferedTokenStream tokens = new Antlr4.Runtime.UnbufferedTokenStream(lexer);
SelectSQLParser parser = new SelectSQLParser(tokens);
var tree = parser.compileUnit();
ParseTreeWalker walker = new ParseTreeWalker();
SelectSQLTreeListener lsn = new SelectSQLTreeListener();
walker.Walk(lsn, tree);
return lsn.SelectStmt;
}
public static SelectStmtInfo ParseSQL(string sql)
{
Antlr4.Runtime.AntlrInputStream input = new Antlr4.Runtime.AntlrInputStream(sql);
SelectSQLLexer lexer = new SelectSQLLexer(input);
ErrorListener errorListner = new ErrorListener();
Antlr4.Runtime.UnbufferedTokenStream tokens = new Antlr4.Runtime.UnbufferedTokenStream(lexer);
SelectSQLParser parser = new SelectSQLParser(tokens);
parser.AddErrorListener(errorListner);
var tree = parser.compileUnit();
ParseTreeWalker walker = new ParseTreeWalker();
SelectSQLTreeListener lsn = new SelectSQLTreeListener();
walker.Walk(lsn, tree);
return(lsn.SelectStmt);
}
public override void EnterColumn(SelectSQLParser.ColumnContext context)
{
Column column = new Column();
if (context.columnExpression().IsEmpty) //不存在列表达式
throw new MissingColumnExpressionException();
var functionalColumn = context.columnExpression().functionableColumn();
var columnName = context.columnExpression().columnName();
if (functionalColumn!=null&&!functionalColumn.IsEmpty)
{
column.Expression = new ColumnExpression(ExpressionType.Function);
column.Expression.Function = new FunctionDescription();
}
else if (columnName!=null&&!columnName.IsEmpty)
{
column.Expression = new ColumnExpression(ExpressionType.ColumnName);
column.Expression.ColumnName = columnName.GetText();
}
else
{
throw new MissingColumnExpressionException();
}
if (context.AS() != null) //存在别名
{
columnName = context.columnName();
if (columnName.IsEmpty) //语法错误
throw new MissingColumnAliasException();
column.HasAlias = true;
column.Alias = columnName.GetText();
}
this.SelectStmt.Columns.Add(column);
}
private static WhereCondition GenerateStatementNode(SelectSQLParser.WhereStmtContext whereStmt)
{
var andOr = whereStmt.AND_OR();
var subWhereStmts = whereStmt.whereStmt();
var whereCondition = whereStmt.whereCondition();
if (whereCondition != null && !whereCondition.IsEmpty) //普通单项where条件
return GenerateConditionNode(whereCondition);
if (subWhereStmts == null || subWhereStmts.Length<2)
throw new MissingWhereConditionException();
//父节点，非单项where条件
var stmtNode = new WhereCondition(WhereConditionNodeType.Statement);
var leftWhereStmt = subWhereStmts.First();
var rightWhereStmt = subWhereStmts.Last();
stmtNode.Statement_LeftNode = GenerateStatementNode(leftWhereStmt);
stmtNode.Statement_Operator = andOr.GetText();
stmtNode.Statement_RightNode = GenerateStatementNode(rightWhereStmt);
return stmtNode;
}
private static WhereCondition GenerateConditionNode(SelectSQLParser.WhereConditionContext whereCondition)
{
var wcInfo = new WhereCondition(WhereConditionNodeType.Condition);
wcInfo.Condition_LeftExpression = whereCondition.comparableValue().First().GetText();
wcInfo.Condition_Operator = whereCondition.operators().GetText();
wcInfo.Condition_RightExpression = whereCondition.comparableValue().Last().GetText();
return wcInfo;
}
public override void EnterWhereStmts(SelectSQLParser.WhereStmtsContext context)
{
var whereStmt = context.whereStmt();
if (whereStmt == null || whereStmt.IsEmpty)
throw new MissingWhereConditionException();
this.SelectStmt.WhereCondition = GenerateStatementNode(whereStmt);
}
public override void EnterTable(SelectSQLParser.TableContext context)
{
var tableName = context.identity().GetText();
if (string.IsNullOrEmpty(tableName))
throw new MissingTableNameException();
}
public override void EnterSelect(SelectSQLParser.SelectContext context)
{
if (context.COLUMN_PREDICT() != null)
{
this.SelectStmt.Column_PredictExists=true;
this.SelectStmt.Column_PredictWord = context.COLUMN_PREDICT().GetText();
}
}
public override void EnterOrderByStmt(SelectSQLParser.OrderByStmtContext context)
{
var orderBy = new OrderByCondition();
var expression = context.columnExpression();
if (expression == null || expression.IsEmpty)
throw new MissingOrderByException();
orderBy.Expression = expression.GetText();
if (string.IsNullOrEmpty(orderBy.Expression))
throw new MissingOrderByException();
orderBy.Direction = OrderByDirection.DESC;
var direction = context.orderByDirection();
if (direction == null || direction.IsEmpty)
orderBy.Direction = OrderByDirection.ASC;
else if(direction.GetText().Equals("asc", StringComparison.OrdinalIgnoreCase))
orderBy.Direction = OrderByDirection.ASC;
this.SelectStmt.OrderBy.Add(orderBy);
}