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执行SQL语句，操作实盘数据库的数据库接口函数。


    
    
    
DBExec(sql)

    
    
    
DBExec(sql, ...args)

示例

  • 支持内存数据库：调用DBExec函数时，如果sql语句以:开头，则在内存数据库中执行操作。由于不写入文件，执行速度更快，适用于无需持久化保存的数据库操作，例如：

    
    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)

    // 插入一条数据
    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)

    # 插入一条数据
    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;"))
    
    rust
    
    
    fn main() {
    let 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)",
    ];
    let strSql = arr.join("");
    let ret = DBExec(&strSql);
    Log!(format!("{:?}", ret));

    // 插入一条数据
    Log!(format!("{:?}", 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!(format!("{:?}", DBExec(":SELECT * FROM TEST_TABLE;")));
}

  • 使用DBExec()函数在数据库中创建数据表。

    
    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)
    
    rust
    
    
    fn main() {
    let 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)",
    ];
    let strSql = arr.join("");
    let ret = DBExec(&strSql);
    Log!(format!("{:?}", ret));
}

  • 对表中记录执行增、删、查、改操作。

    
    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))

    // 插入一条记录
    Log(DBExec("INSERT INTO TEST_TABLE (TS, HIGH, OPEN, LOW, CLOSE, VOLUME) VALUES (1518970320000, 100, 99.1, 90, 100, 12345.6);"))

    // 查询记录
    Log(DBExec("SELECT * FROM TEST_TABLE;"))

    // 更新记录
    Log(DBExec("UPDATE TEST_TABLE SET HIGH=? WHERE TS=?", 110, 1518970320000))

    // 删除记录
    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))

    # 插入一条记录
    Log(DBExec("INSERT INTO TEST_TABLE (TS, HIGH, OPEN, LOW, CLOSE, VOLUME) VALUES (1518970320000, 100, 99.1, 90, 100, 12345.6);"))

    # 查询记录
    Log(DBExec("SELECT * FROM TEST_TABLE;"))

    # 更新记录
    Log(DBExec("UPDATE TEST_TABLE SET HIGH=? WHERE TS=?", 110, 1518970320000))

    # 删除记录
    Log(DBExec("DELETE FROM TEST_TABLE WHERE HIGH=?", 110))
    
    rust
    
    
    fn main() {
    let 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)",
    ];
    let strSql = arr.join("");
    Log!(format!("{:?}", DBExec(&strSql)));

    // 插入一条记录
    Log!(format!("{:?}", DBExec("INSERT INTO TEST_TABLE (TS, HIGH, OPEN, LOW, CLOSE, VOLUME) VALUES (1518970320000, 100, 99.1, 90, 100, 12345.6);")));

    // 查询记录
    Log!(format!("{:?}", DBExec("SELECT * FROM TEST_TABLE;")));

    // 更新记录：Rust 版 DBExec() 函数仅接受单个 SQL 语句字符串参数，不支持 ? 占位符传参，参数值需直接写入语句中
    Log!(format!("{:?}", DBExec("UPDATE TEST_TABLE SET HIGH=110 WHERE TS=1518970320000;")));

    // 删除记录
    Log!(format!("{:?}", DBExec("DELETE FROM TEST_TABLE WHERE HIGH=110;")));
}

返回值

类型描述

object

SQL语句的执行结果：columns为列名数组，values为由各行数据组成的二维数组，例如{"columns":["TS","CLOSE"],"values":[[1518970320000,100]]}；结构详见DBExec-return。

参数

名称类型必填描述

sql

string

是

要执行的sql语句字符串。

arg

string / number / bool / 空值

否

sql语句中?占位符对应的参数值，按顺序传入，可传入多个arg参数。仅JavaScript、Python支持该参数，Rust的DBExec()只接受sql语句这一个参数。

参考

_G

备注

  • 函数DBExec()通过传入参数来操作实盘数据库（SQLite数据库）。
  • 支持对实盘数据库中的数据进行增、删、查、改等操作，支持SQLite语法。
  • 非查询语句可一次写入多条，以分号分隔（例如一次创建多张表及其索引），并按顺序逐条执行；?占位符的参数按顺序依次分配给各条语句，函数返回最后一条语句的执行结果。若某条语句执行出错，函数会报错，但该语句之前的语句已执行完成。
  • 实盘数据库中的系统保留表包括：kvdb、cfg、log、profit、chart，切勿对这些表进行操作。
  • 目前不支持事务，不建议执行事务相关操作，否则会引起系统冲突。
  • DBExec()函数仅支持实盘。