Teradata各种类型Show 语句

根据上一篇中的TableKind类型可以写相应的show table 语句。

Teradata中TableKind与show语句对应

TableKind	类型	show语句
T	SET Table	show table 表名;
O	MULTISET Table	show table 表名;
V	View	show view 视图名;
M	Macro	show macro 名;
P	SQL Procedure	show procedure 名;
E	External Stored Procedure	show procedure 名;
D	JAR
R	Table function	show function 名;
F	Standard function	show function 名;
G	TRIGGER	SHOW TRIGGER trigger_name;
I	Join Index	SHOW JOIN INDEX join_index_name;
N	Hash Index	SHOW HASH INDEX hash_index_name;
其他

下面是一段示例代码，代码实现使用show语句获取各种Table（Object）的DDL（Create语句等）以及对应的Drop语句：

	/**
	 * 
	 * @param TableName : The name of Production DB's table
	 * @param TableKind : The kind of table 
	 * @return
	 * @throws SQLException
	 */
	private String showTable(String TableName, String TableKind) 
			throws SQLException {
		String sqlCREATE = "";
		PreparedStatement ps = null;
		ResultSet rs = null;
		String sql = null;
		switch(TableKind) {
		case "T":
			sql = CommonConfig.sqlShowTable + "\"" + TableName + "\"";
			this.sqlListDrop.add(CommonConfig.sqlDropTable + 
					"\"" + TableName + "\"");
			break;
		case "V":
			sql = CommonConfig.sqlShowView + "\"" + TableName + "\"";
			this.sqlListDrop.add(CommonConfig.sqlDropView + 
					"\"" + TableName + "\"");
			break;
		case "M":
			sql = CommonConfig.sqlShowMacro + "\"" + TableName + "\"";
			this.sqlListDrop.add(CommonConfig.sqlDropMacro + 
					"\"" + TableName + "\"");
			break;
		case "P":
		case "E":
			sql = CommonConfig.sqlShowProcedure + "\"" + TableName + "\"";
			this.sqlListDrop.add(CommonConfig.sqlDropProcedure + 
					"\"" + TableName + "\"");
			break;
		case "D":
			logger.info(" -- TableKind is D, SKIP. -- ");
			break;
		case "R":
		case "F":
			sql = CommonConfig.sqlShowFunction + "\"" + TableName + "\"";
			this.sqlListDrop.add(CommonConfig.sqlDropFunction + 
					"\"" + TableName + "\"");
			break;
		default:
			break;
		}
		logger.info(sql);
		if(sql == null) return null;
		ps = conn.prepareStatement(sql);
		//logger.info(sql);
		rs = ps.executeQuery();
		while(rs.next()) {
			// Be careful, replace = with +=
			sqlCREATE += rs.getString(1);
		}
		
		// Remove the DB name in the CREATE statement
		sqlCREATE = sqlCREATE.replace(DBConn.getDatabase() + ".", "");
		sqlCREATE = sqlCREATE.replace(DBConn.getDatabase().toLowerCase() + ".", "");
		sqlCREATE = sqlCREATE.replace(DBConn.getDatabase().toUpperCase() + ".", "");
		sqlCREATE = sqlCREATE.replace("\"" + DBConn.getDatabase() + "\".", "");
		sqlCREATE = sqlCREATE.replace("\"" + DBConn.getDatabase().toLowerCase() + "\".", "");
		sqlCREATE = sqlCREATE.replace("\"" + DBConn.getDatabase().toUpperCase() + "\".", "");
		rs.close();
		ps.close();
		
		return sqlCREATE;
	}

注意：

1. CommonConfig.sqlShowTable是字符串"show table "，其他类似。

2. 最值得注意的情况是

sqlCREATE += rs.getString(1);

这句必须使用+=，而不能使用=；因为存在show procedure的结果集（ResultSet）有可能是当作多行返回的。即如下图的情况（使用=时的返回值）：

 INFO [main] (DDLTransfer.java:93) - show procedure "wikiproc"
**************************************
replace procedure 
**************************************
wikiproc
**************************************
(IN RUNID INTEGER)
dynamic result sets 1
main:begin

  declare cur_report cursor with return only for
  sel *
  from pct_run r 
  where r.run_id=RUNID;

  open cur_report;
end;

每行用一行星号隔开，可见返回了三行。