DBExec

数据库接口函数。

    
    
    
DBExec(sql)

示例

• 支持内存数据库。对于DBExec函数的参数，如果sql语句以:开头，则在内存数据库中执行操作，无需写入文件，执行速度更快。

  适用于无需持久化保存的数据库操作场景，例如：

  • javascript
  • python
  • cpp

  
      javascript
      
      
  function main() {
      var strSql = [
          ":CREATE TABLE TEST_TABLE(",
          "TS INT PRIMARY KEY NOT NULL,",
          "HIGH REAL NOT NULL,",
          "OPEN REAL NOT NULL,",
          "LOW REAL NOT NULL,",
          "CLOSE REAL NOT NULL,",
          "VOLUME REAL NOT NULL)"
      ].join("")
      var ret = DBExec(strSql)
      Log(ret)
  
      // 增加一条数据
      Log(DBExec(":INSERT INTO TEST_TABLE (TS, HIGH, OPEN, LOW, CLOSE, VOLUME) VALUES (1518970320000, 100, 99.1, 90, 100, 12345.6);"))
  
      // 查询数据
      Log(DBExec(":SELECT * FROM TEST_TABLE;"))
  }
  

  
      python
      
      
  def main():
      arr = [
          ":CREATE TABLE TEST_TABLE(",
          "TS INT PRIMARY KEY NOT NULL,",
          "HIGH REAL NOT NULL,",
          "OPEN REAL NOT NULL,",
          "LOW REAL NOT NULL,",
          "CLOSE REAL NOT NULL,",
          "VOLUME REAL NOT NULL)"
      ]
      strSql = ""
      for i in range(len(arr)):
          strSql += arr[i]
      ret = DBExec(strSql)
      Log(ret)
  
      # 增加一条数据
      Log(DBExec(":INSERT INTO TEST_TABLE (TS, HIGH, OPEN, LOW, CLOSE, VOLUME) VALUES (1518970320000, 100, 99.1, 90, 100, 12345.6);"))
  
      # 查询数据
      Log(DBExec(":SELECT * FROM TEST_TABLE;"))
  

  
      c++
      
      
  void main() {
      string strSql = ":CREATE TABLE TEST_TABLE(\
          TS INT PRIMARY KEY NOT NULL,\
          HIGH REAL NOT NULL,\
          OPEN REAL NOT NULL,\
          LOW REAL NOT NULL,\
          CLOSE REAL NOT NULL,\
          VOLUME REAL NOT NULL)";
      auto ret = DBExec(strSql);
      Log(ret);
  
      // 增加一条数据
      Log(DBExec(":INSERT INTO TEST_TABLE (TS, HIGH, OPEN, LOW, CLOSE, VOLUME) VALUES (1518970320000, 100, 99.1, 90, 100, 12345.6);"));
  
      // 查询数据
      Log(DBExec(":SELECT * FROM TEST_TABLE;"));
  }
  

• 创建数据表。

  • javascript
  • python
  • cpp

  
      javascript
      
      
  function main() {
      var strSql = [
          "CREATE TABLE TEST_TABLE(",
          "TS INT PRIMARY KEY NOT NULL,",
          "HIGH REAL NOT NULL,",
          "OPEN REAL NOT NULL,",
          "LOW REAL NOT NULL,",
          "CLOSE REAL NOT NULL,",
          "VOLUME REAL NOT NULL)"
      ].join("")
      var ret = DBExec(strSql)
      Log(ret)
  }
  

  
      python
      
      
  def main():
      arr = [
          "CREATE TABLE TEST_TABLE(",
          "TS INT PRIMARY KEY NOT NULL,",
          "HIGH REAL NOT NULL,",
          "OPEN REAL NOT NULL,",
          "LOW REAL NOT NULL,",
          "CLOSE REAL NOT NULL,",
          "VOLUME REAL NOT NULL)"
      ]
      strSql = ""
      for i in range(len(arr)):
          strSql += arr[i]
      ret = DBExec(strSql)
      Log(ret)
  

  
      c++
      
      
  void main() {
      string strSql = "CREATE TABLE TEST_TABLE(\
          TS INT PRIMARY KEY NOT NULL,\
          HIGH REAL NOT NULL,\
          OPEN REAL NOT NULL,\
          LOW REAL NOT NULL,\
          CLOSE REAL NOT NULL,\
          VOLUME REAL NOT NULL)";
      auto ret = DBExec(strSql);
      Log(ret);
  }
  

• 数据表记录的增删查改操作。

  • javascript
  • python
  • cpp

  
      javascript
      
      
  function main() {
      var strSql = [
          "CREATE TABLE TEST_TABLE(",
          "TS INT PRIMARY KEY NOT NULL,",
          "HIGH REAL NOT NULL,",
          "OPEN REAL NOT NULL,",
          "LOW REAL NOT NULL,",
          "CLOSE REAL NOT NULL,",
          "VOLUME REAL NOT NULL)"
      ].join("")
      Log(DBExec(strSql))
  
      // 增加一条数据
      Log(DBExec("INSERT INTO TEST_TABLE (TS, HIGH, OPEN, LOW, CLOSE, VOLUME) VALUES (1518970320000, 100, 99.1, 90, 100, 12345.6);"))
  
      // 查询数据
      Log(DBExec("SELECT * FROM TEST_TABLE;"))
  
      // 修改数据
      Log(DBExec("UPDATE TEST_TABLE SET HIGH=? WHERE TS=?", 110, 1518970320000))
  
      // 删除数据
      Log(DBExec("DELETE FROM TEST_TABLE WHERE HIGH=?", 110))
  }
  

  
      python
      
      
  def main():
      arr = [
          "CREATE TABLE TEST_TABLE(",
          "TS INT PRIMARY KEY NOT NULL,",
          "HIGH REAL NOT NULL,",
          "OPEN REAL NOT NULL,",
          "LOW REAL NOT NULL,",
          "CLOSE REAL NOT NULL,",
          "VOLUME REAL NOT NULL)"
      ]
      strSql = ""
      for i in range(len(arr)):
          strSql += arr[i]
      Log(DBExec(strSql))
  
      # 增加一条数据
      Log(DBExec("INSERT INTO TEST_TABLE (TS, HIGH, OPEN, LOW, CLOSE, VOLUME) VALUES (1518970320000, 100, 99.1, 90, 100, 12345.6);"))
  
      # 查询数据
      Log(DBExec("SELECT * FROM TEST_TABLE;"))
  
      # 修改数据
      Log(DBExec("UPDATE TEST_TABLE SET HIGH=? WHERE TS=?", 110, 1518970320000))
  
      # 删除数据
      Log(DBExec("DELETE FROM TEST_TABLE WHERE HIGH=?", 110))
  

  
      c++
      
      
  void main() {
      string strSql = "CREATE TABLE TEST_TABLE(\
          TS INT PRIMARY KEY NOT NULL,\
          HIGH REAL NOT NULL,\
          OPEN REAL NOT NULL,\
          LOW REAL NOT NULL,\
          CLOSE REAL NOT NULL,\
          VOLUME REAL NOT NULL)";
      Log(DBExec(strSql));
  
      // 增加一条数据
      Log(DBExec("INSERT INTO TEST_TABLE (TS, HIGH, OPEN, LOW, CLOSE, VOLUME) VALUES (1518970320000, 100, 99.1, 90, 100, 12345.6);"));
  
      // 查询数据
      Log(DBExec("SELECT * FROM TEST_TABLE;"));
  
      // 修改数据
      Log(DBExec("UPDATE TEST_TABLE SET HIGH=? WHERE TS=?", 110, 1518970320000));
  
      // 删除数据
      Log(DBExec("DELETE FROM TEST_TABLE WHERE HIGH=?", 110));
  }
  

返回值

            json
            
            
{"columns":["TS","HIGH","OPEN","LOW","CLOSE","VOLUME"],"values":[[1518970320000,100,99.1,90,100,12345.6]]}

参数

参考

备注

函数DBExec()通过传入参数，可以操作实盘数据库（SQLite数据库），实现对实盘数据库中数据的增、删、查、改等操作，支持SQLite语法。实盘数据库中的系统保留表包括：kvdb、cfg、log、profit、chart，请勿对这些表进行操作。目前不支持事务操作，不建议执行此类操作，以免引起系统冲突。DBExec()函数仅支持实盘环境。