DBExec

Database interface function.

    
    
    
DBExec(sql)

Examples

• Supports in-memory database. For the DBExec function parameters, if the SQL statement starts with :, it operates in the in-memory database without writing to files, which is faster. Suitable for database operations that don't require persistent storage, for example:

  • 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(\n        TS INT PRIMARY KEY NOT NULL,\n        HIGH REAL NOT NULL,\n        OPEN REAL NOT NULL,\n        LOW REAL NOT NULL,\n        CLOSE REAL NOT NULL,\n        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;"));
  }
  

• Use the DBExec() function to create a table.

  • 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);
  }
  

• CRUD operations on table records.

  • 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));
  }
  

Returns

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

Arguments

See Also

Remarks

• The function DBExec() can operate on the live trading database (SQLite database) through passed parameters.

• Implements operations such as insert, delete, query, and update on data in the live trading database, supporting SQLite syntax.

• System reserved tables in the live trading database: kvdb, cfg, log, profit, chart. Please do not operate on these tables.

• Currently does not support transactions. Such operations are not recommended as they may cause system conflicts.

• The DBExec() function only supports live trading environment.