1、数据库链接(打开数据库)->传统方式创建表
let path = Bundle.main.path(forResource: "test", ofType:".db")
print(path!)
let db = try! Connection(path!)
try! db.execute("create table t_teacher(name text, email text)")
2、构建创建表SQL
let users = Table("users")
let id = Expression<Int>("id")
let name = Expression<String>("name")
let email = Expression<String?>("email")
let sql = users.create { (t) in
t.column(id)
t.column(name)
t.column(email)
}
print(sql)
3、执行动态SQL(主键，唯一，不能够为空)
try! db.run(sql)
4、插入数据
let insert = users.insert(id <- 2, name <- "NSError", email <- "nserror@qq.com")
try! db.run(insert)
5、更新数据 + 删除数据
- 更新所有行
let update = users.update(email <- "dream@qq.com", name <- "andy")
print(update.asSQL())
try! db.run(update)
- 条件更新
let filter = users.filter(name == "andy")
try! db.run(filter.update(email <- "dream@qq.com"))
- 内容替换
let filter1 = users.filter(id == 1)
try! db.run(filter1.update(name <- name.replace("r", with: "i")))
- 删除所有
try! db.run(users.delete())
- 条件删除->where条件
let alice = users.filter(id == 1)
let delete = alice.delete()
print(delete.asSQL())
try! db.run(delete)
6、查询数据
- 查询所有
let seq:AnySequence = try! db.prepare(users)
for user in seq {
//user->Row->表示一行数据
print("name: \(user[name]), email: \(user[email])")
}
- 条件查询->子段查询->只查询某些字段
for user in try! db.prepare(users.select(name)) {
print("name: \(user[name])")
}
- 条件查询->"*"查询(所有字段)->通配符
//查询所有特殊方法"*"->特殊字符
for user in try! db.prepare(users.select(*)) {
print("name: \(user[name])")
}
查询子句
- 查询子句->filter->where条件
let query = users.select(email).filter(name == "NSLog")
print(query.asSQL())
let rows = try! db.prepare(query)
for user in rows {
print("name: \(user[email])")
}
- 查询子句->排序"order"
let query = users.select(email, name).order(name.desc)
print(query.asSQL())
let rows = try! db.prepare(query)
for user in rows {
print("name: \(user[email]), phone:\(user[name])")
}
- 查询子句->LIMIT->查询多条->指定查询数据行数
let query = users.select(email).limit(50)
print(query.asSQL())
for user in try! db.prepare(query) {
print("name: \(user[email])")
}
- 查询子句->LIMIT->查询多条->指定查询数据开始位置行数
let query = users.select(email).limit(1, offset: 1)
print(query.asSQL())
for user in try! db.prepare(query) {
print("name: \(user[email])")
}
- 查询子句->LIMIT->查询一条(根据表)->不能指定数量->只有一条
//注意：表中的第一条数据
if let user = try! db.pluck(users) {
print("phone: \(user[name])")
}
- 查询子句->过滤数据->contains
//注意：必需是属性值全称(作为选项)
let filter2 = users.filter(["Andy"].contains(name))
print(filter2.asSQL())
for user in try! db.prepare(filter2) {
print("name: \(user[name])")
}
- 查询子句->过滤数据->模糊查询->like
//后缀：查询以".com"结尾的行数据
//前缀：查询以"andy@"开头的行数据
//中缀：查询以"@"中间条件的行数据
//模糊查询：特殊表示符号"%"
let filter3 = users.filter(name.like("%n%"))
print(filter3.asSQL())
for user in try! db.prepare(filter3) {
print("name: \(user[name]), email: \(user[email])")
}
- 查询子句->过滤数据->多条件查询->重载运算符->"&&"
//例如：sql语句->select * from t_user where name = "Dream" and phone = 3
//数据库框架中表示：&&->and
let filter4 = users.filter( id == "1" && name == "NSError")
print(filter4.asSQL())
for user in try! db.prepare(filter4) {
print("email: \(user[email])")
}
- 查询子句->过滤数据->多条件查询->重载运算符->"||"
//||->"或"满足其中之一即可->对应数据库->"or"
let filter5 = users.filter(name == "love" || name == "NSLog")
print(filter5.asSQL())
for user in try! db.prepare(filter5) {
print("email: \(user[email])")
}
- 查询子句->过滤数据->多条件查询->重载运算符->">="
let filter6 = users.filter(id >= "3")
print(filter6.asSQL())
for user in try! db.prepare(filter6) {
print("email: \(user[email])")
}
- 查询子句->过滤数据->多条件查询->重载运算符->"<="
let filter7 = users.filter(id <= "2")
print(filter7.asSQL())
for user in try! db.prepare(filter7) {
print("email: \(user[email])")
}
- 查询子句->过滤数据->多条件查询->重载运算符->">"
let filter8 = users.filter(name > "2")
print(filter8.asSQL())
for user in try! db.prepare(filter8) {
print("email: \(user[email])")
}
- 查询子句->过滤数据->多条件查询->重载运算符->"<"
let filter9 = users.filter(name < "2")
print(filter9.asSQL())
for user in try! db.prepare(filter9) {
print("email: \(user[email])")
}
- 查询子句->过滤数据->多条件查询->重载运算符->"!="
let filter10 = users.filter(name != "2")
print(filter10.asSQL())
for user in try! db.prepare(filter10) {
print("email: \(user[email])")
}
- 查询子句->过滤数据->大小写转换
// name.lowercaseString == "DREAM"->结果->hello
// uppercaseString->大小->小写
let filter11 = users.filter(name.uppercaseString == "LOVE")
print(filter11.asSQL())
for user in try! db.prepare(filter11) {
print("email: \(user[email])")
}
- 查询子句->过滤数据->Table->where条件
let filter12 = users.where(name == "love")
print(filter12.asSQL())
for user in try! db.prepare(filter12) {
print("email: \(user[email])")
}
- 查询子句->过滤数据->group分组
let filter13 = users.group(name)
print(filter13.asSQL())
for user in try! db.prepare(filter13) {
print("email: \(user[name])")
}
查询函数->scalar
- count->当前表有多少行数据
//获取行数方法
//scalar->执行查询函数
let c = users.count
print(c.asSQL())
let count = try! db.scalar(c)
- count->查询指定条件对应的数据行数
let count = try! db.scalar(users.select(name.count))
print(count)
- max/min->最大值/最小值
let max = try! db.scalar(users.select(name.max))
print(max!)
let min = try! db.scalar(users.select(name.min))
print(min!)
- avg/sum(动态类型)/total->平均值/总和/总和
let average = try! db.scalar(users.select(id.average))
print(average!)
- distinct->有几个分类(不同个数)
let count = try! db.scalar(users.select(name.distinct.count))
print(count)
7、表管理 + 表约束条件 + 事务处理
- 重命名表名->首先：给Table增加rename方法
try! db.run(users.rename(Table("t_user")))
- 添加表字段
//1、第一步：新增添加字段方法
let sex = Expression<String?>("sex")
try! db.run(users.addColumn(sex))
//表约束条件(国外开源项目->牛逼->借鉴了FMDB->演变过来的)
let students = Table("students")
//备注：查询增加
let sid = Expression<Int>("sid")
let sname = Expression<String>("sname")
let semail = Expression<String>("semail")
//1、添加主键
//做一个模版->然后根据我的模版自己尝试去实现其他约束条件
//什么是主键？->核心：唯一性，不能够存在相同的值->自动增长
let ssql = students.create { (t) in
t.column(sid, primaryKey: true)
t.column(sname)
t.column(semail)
}
try! db.run(ssql)
- 事务处理
try! db.transaction {
let insert = users.insert(id <- 5, name <- "efly", email <- "efly@qq.com")
try! db.run(insert)
try! db.run(users.insert(email <- "fan@qq.com"))
//测试一下
//思路
//第一步：设置一个属性不能够为空->null->例如：name属性
//提示：之前讲解添加约束条件方法
//第二步：插入数据->事务管理->报错了
}
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