语法指南 | 优宽量化

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，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)

    // 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;"))


    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));

    // 增加一条数据
    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;")));
}

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));
}

对数据表中记录进行增、删、改、查（增删改查）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))

    // 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))


    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)));

    // 增加一条数据
    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;")));

    // 修改数据，Rust 的 DBExec() 函数只接受单个 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;")));

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

返回值

类型描述

object

包含 sql 语句执行结果的对象，例如：


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

参数

名称	类型	必填	描述
sql	string	是	sql 语句字符串。

参考

_G

备注

函数 DBExec() 通过传入参数操作实盘数据库（SQLite 数据库），可对实盘数据库中的数据执行增、删、查、改等操作，并支持 SQLite 语法。实盘数据库中的系统保留表包括 kvdb、cfg、log、profit、chart，请勿对这些表进行任何操作。目前不支持事务，不建议执行此类操作，否则会引发系统冲突。
DBExec() 函数仅支持实盘。