简介
FreeSql 是一个功能强大的 .NETStandard 库，用于对象关系映射程序(O/RM)，支持 .NETCore 2.1+ 或 .NETFramework 4.6.1+。
定义
IFreeSql fsql = new FreeSql.FreeSqlBuilder()
.UseConnectionString(FreeSql.DataType.Sqlite,
@"Data Source=|DataDirectory|/test.db;Pooling=true;Max Pool Size=10")
.UseAutoSyncStructure(true) //自动同步实体结构到数据库
.Build();入门篇
查询
1、查询一条
fsql.Select.Where(a => a.Id == 1).First(); 2、分页：第1页，每页20条
fsql.Select.Page(1, 20).ToList(); 细节说明：SqlServer 2012 以前的版本，使用 row_number 分页；SqlServer 2012+ 版本，使用最新的 fetch next rows 分页；
3、IN
fsql.Select.Where(a => new { 1,2,3 }.Contains(a.Id)).ToList(); 4、联表
fsql.Select.LeftJoin((a, b) => a.YyyId == b.Id).ToList(); 5、Exists子表
fsql.Select.Where(a => fsql.Select(b => b.Id == a.YyyId).Any()).ToList(); 6、GroupBy & Having
fsql.Select.GroupBy(a => new { a.CategoryId }).Having(a => a.Count > 2).ToList(a => new { a.Key, a.Count() }); 7、指定字段查询
fsql.Select.Limit(10).ToList(a => a.Id);
fsql.Select.Limit(10).ToList(a => new { a.Id, a.Name });
fsql.Select.Limit(10).ToList(a => new Dto()); 8、执行SQL返回实体
fsql.Ado.Query("select * from xxx");
fsql.Ado.Query<(int, string, string)>("select * from xxx");
fsql.Ado.Query("select * from xxx"); 插入
1、单条
fsql.Insert().AppendData(new Xxx()).ExecuteAffrows(); 2、单条，返回自增值
fsql.Insert().AppendData(new Xxx()).ExecuteIdentity(); 3、单条，返回插入的行（SqlServer 的 output 特性）
fsql.Insert().AppendData(new Xxx()).ExecuteInserted(); 4、批量
fsql.Insert().AppendData(数组).ExecuteAffrows(); 5、批量，返回插入的行（SqlServer 的 output 特性）
fsql.Insert().AppendData(数组).ExecuteInserted(); 6、指定列
fsql.Insert().AppendData(new Xxx()).InsertColumns(a => a.Title).ExecuteAffrows();
fsql.Insert().AppendData(new Xxx()).InsertColumns(a => new { a.Id, a.Title}).ExecuteAffrows(); 7、忽略列
fsql.Insert().AppendData(new Xxx()).IgnoreColumns(a => a.Title).ExecuteAffrows();
fsql.Insert().AppendData(new Xxx()).IgnoreColumns(a => new { a.Id, a.Title}).ExecuteAffrows(); 8、事务
fsql.Insert().AppendData(new Xxx()).WithTransaction(事务对象).ExecuteAffrows(); 更新
1、指定列
fsql.Update(1).Set(a => a.CreateTime, DateTime.Now).ExecuteAffrows(); 2、累加，set clicks = clicks + 1
fsql.Update(1).Set(a => a.Clicks + 1).ExecuteAffrows(); 3、保存
fsql.Update().SetSource(单个实体).ExecuteAffrows(); 4、批量保存
fsql.Update().SetSource(数组).ExecuteAffrows(); 5、忽略列
fsql.Update().SetSource(数组).IgnoreColumns(a => new { a.Clicks, a.CreateTime }).ExecuteAffrows(); 6、更新条件
fsql.Update().SetSource(数组).Where(a => a.Clicks > 100).ExecuteAffrows(); 7、事务
fsql.Update(1).Set(a => a.Clicks + 1).WithTransaction(事务对象).ExecuteAffrows(); 删除
1、dywhere
- 主键值
- new[] { 主键值1, 主键值2 }
- Xxx对象
- new[] { Xxx对象1, Xxx对象2 }
- new { id = 1 }
fsql.Delete(new[] { 1, 2 }).ExecuteAffrows();
//DELETE FROM `xxx` WHERE (`Id` = 1 OR `Id` = 2)
fsql.Delete(new Xxx { Id = 1, Title = "test" }).ExecuteAffrows();
//DELETE FROM `xxx` WHERE (`Id` = 1)
fsql.Delete(new[] { new Xxx { Id = 1, Title = "test" }, new Xxx { Id = 2, Title = "test" } }).ExecuteAffrows();
//DELETE FROM `xxx` WHERE (`Id` = 1 OR `Id` = 2)
fsql.Delete(new { id = 1 }).ExecuteAffrows();
//DELETE FROM `xxx` WHERE (`Id` = 1) 2、条件
fsql.Delete().Where(a => a.Id == 1).ExecuteAffrows();
//DELETE FROM `xxx` WHERE (`Id` = 1)
fsql.Delete().Where("id = ?id", new { id = 1 }).ExecuteAffrows();
//DELETE FROM `xxx` WHERE (id = ?id)
var item = new Xxx { Id = 1, Title = "newtitle" };
var t7 = fsql.Delete().Where(item).ExecuteAffrows();
//DELETE FROM `xxx` WHERE (`Id` = 1)
var items = new List();
for (var a = 0; a < 10; a++) items.Add(new Xxx { Id = a + 1, Title = $"newtitle{a}", Clicks = a * 100 });
fsql.Delete().Where(items).ExecuteAffrows();
//DELETE FROM `xxx` WHERE (`Id` IN (1,2,3,4,5,6,7,8,9,10)) 3、事务
fsql.Delete().Where(a => a.Id == 1).WithTransaction(事务对象).ExecuteAffrows(); 初级篇
表达式
支持功能丰富的表达式函数解析，方便程序员在不了解数据库函数的情况下编写代码。这是 FreeSql 非常特色的功能之一，深入细化函数解析尽量做到满意，所支持的类型基本都可以使用对应的表达式函数，例如 日期、字符串、IN查询、数组（PostgreSQL的数组）、字典（PostgreSQL HStore)等等。
1、查找今天创建的数据
fsql.Delete().Where(a => a.CreateTime.Date == DateTime.Now.Date).ToList(); 2、SqlServer 下随机获取记录
fsql.Delete().OrderBy(a => Guid.NewGuid()).Limit(1).ToSql(); 4、表达式函数全览
| 表达式 | MySql | SqlServer | PostgreSQL | Oracle | 功能说明 |
|---|---|---|---|---|---|
| a ? b : c | case when a then b else c end | case when a then b else c end | case when a then b else c end | case when a then b else c end | a成立时取b值，否则取c值 |
| a ?? b | ifnull(a, b) | isnull(a, b) | coalesce(a, b) | nvl(a, b) | 当a为null时，取b值 |
| 数字 + 数字 | a + b | a + b | a + b | a + b | 数字相加 |
| 数字 + 字符串 | concat(a, b) | cast(a as varchar) + cast(b as varchar) | case(a as varchar) + b | a+b | 字符串相加，a或b任意一个为字符串时 |
| a - b | a - b | a - b | a - b | a - b | 减 |
| a * b | a * b | a * b | a * b | a * b | 乘 |
| a / b | a / b | a / b | a / b | a / b | 除 |
| a % b | a % b | a % b | a % b | mod(a,b) | 模 |
等等...
5、数组
| 表达式 | MySql | SqlServer | PostgreSQL | Oracle | 功能说明 |
|---|---|---|---|---|---|
| a.Length | - | - | case when a is null then 0 else array_length(a,1) end | - | 数组长度 |
| 常量数组.Length | - | - | array_length(array[常量数组元素逗号分割],1) | - | 数组长度 |
| a.Any() | - | - | case when a is null then 0 else array_length(a,1) end > 0 | - | 数组是否为空 |
| 常量数组.Contains(b) | b in (常量数组元素逗号分割) | b in (常量数组元素逗号分割) | b in (常量数组元素逗号分割) | b in (常量数组元素逗号分割) | IN查询 |
| a.Contains(b) | - | - | a @> array[b] | - | a数组是否包含b元素 |
| a.Concat(b) | - | - | a + b | - | 数组相连 |
| a.Count() | - | - | 同 Length | - | 数组长度 |
一个细节证明 FreeSql 匠心制作
通用的 in 查询 select.Where(a => new []{ 1,2,3 }.Contains(a.xxx))
假设 xxxs 是 pgsql 的数组字段类型，其实会与上面的 in 查询起冲突，FreeSql 解决了这个矛盾 select.Where(a => a.xxxs.Contains(1))
6、字典 Dictionary
| 表达式 | MySql | SqlServer | PostgreSQL | Oracle | 功能说明 |
|---|---|---|---|---|---|
| a.Count | - | - | case when a is null then 0 else array_length(akeys(a),1) end | - | 字典长度 |
| a.Keys | - | - | akeys(a) | - | 返回字典所有key数组 |
| a.Values | - | - | avals(a) | - | 返回字典所有value数组 |
| a.Contains(b) | - | - | a @> b | - | 字典是否包含b |
| a.ContainsKey(b) | - | - | a? b | - | 字典是否包含key |
| a.Concat(b) | - | - | a + b | - | 字典相连 |
| a.Count() | - | - | 同 Count | - | 字典长度 |
7、JSON JToken/JObject/JArray
| 表达式 | MySql | SqlServer | PostgreSQL | Oracle | 功能说明 |
|---|---|---|---|---|---|
| a.Count | - | - | jsonb_array_length(coalesce(a, '[])) | - | json数组类型的长度 |
| a.Any() | - | - | jsonb_array_length(coalesce(a, '[])) > 0 | - | json数组类型，是否为空 |
| a.Contains(b) | - | - | coalesce(a, '{}') @> b::jsonb | - | json中是否包含b |
| a.ContainsKey(b) | - | - | coalesce(a, '{}') ? b | - | json中是否包含键b |
| a.Concat(b) | - | - | coalesce(a, '{}') + b::jsonb | - | 连接两个json |
| Parse(a) | - | - | a::jsonb | - | 转化字符串为json类型 |
8、字符串
| 表达式 | MySql | SqlServer | PostgreSQL | Oracle | Sqlite |
|---|---|---|---|---|---|
| string.Empty | '' | '' | '' | '' | |
| string.IsNullOrEmpty(a) | (a is null or a = '') | (a is null or a = '') | (a is null or a = '') | (a is null or a = '') | (a is null or a = '') |
| a.CompareTo(b) | strcmp(a, b) | - | case when a = b then 0 when a > b then 1 else -1 end | case when a = b then 0 when a > b then 1 else -1 end | case when a = b then 0 when a > b then 1 else -1 end |
| a.Contains('b') | a like '%b%' | a like '%b%' | a ilike'%b%' | a like '%b%' | a like '%b%' |
| a.EndsWith('b') | a like '%b' | a like '%b' | a ilike'%b' | a like '%b' | a like '%b' |
| a.IndexOf(b) | locate(a, b) - 1 | locate(a, b) - 1 | strpos(a, b) - 1 | instr(a, b, 1, 1) - 1 | instr(a, b) - 1 |
| a.Length | char_length(a) | len(a) | char_length(a) | length(a) | length(a) |
| a.PadLeft(b, c) | lpad(a, b, c) | - | lpad(a, b, c) | lpad(a, b, c) | lpad(a, b, c) |
| a.PadRight(b, c) | rpad(a, b, c) | - | rpad(a, b, c) | rpad(a, b, c) | rpad(a, b, c) |
| a.Replace(b, c) | replace(a, b, c) | replace(a, b, c) | replace(a, b, c) | replace(a, b, c) | replace(a, b, c) |
| a.StartsWith('b') | a like 'b%' | a like 'b%' | a ilike'b%' | a like 'b%' | a like 'b%' |
| a.Substring(b, c) | substr(a, b, c + 1) | substring(a, b, c + 1) | substr(a, b, c + 1) | substr(a, b, c + 1) | substr(a, b, c + 1) |
| a.ToLower | lower(a) | lower(a) | lower(a) | lower(a) | lower(a) |
| a.ToUpper | upper(a) | upper(a) | upper(a) | upper(a) | upper(a) |
| a.Trim | trim(a) | trim(a) | trim(a) | trim(a) | trim(a) |
| a.TrimEnd | rtrim(a) | rtrim(a) | rtrim(a) | rtrim(a) | rtrim(a) |
| a.TrimStart | ltrim(a) | ltrim(a) | ltrim(a) | ltrim(a) | ltrim(a) |
使用字符串函数可能会出现性能瓶颈，虽然不推荐使用，但是作为功能库这也是不可缺少的功能之一。
9、日期
| 表达式 | MySql | SqlServer | PostgreSQL | Oracle |
|---|---|---|---|---|
| DateTime.Now | now() | getdate() | current_timestamp | systimestamp |
| DateTime.UtcNow | utc_timestamp() | getutcdate() | (current_timestamp at time zone 'UTC') | sys_extract_utc(systimestamp) |
| DateTime.Today | curdate | convert(char(10),getdate(),120) | current_date | trunc(systimestamp) |
| DateTime.MaxValue | cast('9999/12/31 23:59:59' as datetime) | '9999/12/31 23:59:59' | '9999/12/31 23:59:59'::timestamp | to_timestamp('9999-12-31 23:59:59','YYYY-MM-DD HH24:MI:SS.FF6') |
| DateTime.MinValue | cast('0001/1/1 0:00:00' as datetime) | '1753/1/1 0:00:00' | '0001/1/1 0:00:00'::timestamp | to_timestamp('0001-01-01 00:00:00','YYYY-MM-DD HH24:MI:SS.FF6') |
| DateTime.Compare(a, b) | a - b | a - b | extract(epoch from a::timestamp-b::timestamp) | extract(day from (a-b)) |
| DateTime.DaysInMonth(a, b) | dayofmonth(last_day(concat(a, '-', b, '-1'))) | datepart(day, dateadd(day, -1, dateadd(month, 1, cast(a as varchar) + '-' + cast(b as varchar) + '-1'))) | extract(day from (a | |
| DateTime.Equals(a, b) | a = b | a = b | a = b | a = b |
| DateTime.IsLeapYear(a) | a%4=0 and a%100<>0 or a%400=0 | a%4=0 and a%100<>0 or a%400=0 | a%4=0 and a%100<>0 or a%400=0 | mod(a,4)=0 AND mod(a,100)<>0 OR mod(a,400)=0 |
| DateTime.Parse(a) | cast(a as datetime) | cast(a as datetime) | a::timestamp | to_timestamp(a,'YYYY-MM-DD HH24:MI:SS.FF6') |
| a.Add(b) | date_add(a, interval b microsecond) | dateadd(millisecond, b / 1000, a) | a::timestamp+(b | |
| a.AddDays(b) | date_add(a, interval b day) | dateadd(day, b, a) | a::timestamp+(b | |
| a.AddHours(b) | date_add(a, interval b hour) | dateadd(hour, b, a) | a::timestamp+(b | |
| a.AddMilliseconds(b) | date_add(a, interval b*1000 microsecond) | dateadd(millisecond, b, a) | a::timestamp+(b | |
| a.AddMinutes(b) | date_add(a, interval b minute) | dateadd(minute, b, a) | a::timestamp+(b | |
| a.AddMonths(b) | date_add(a, interval b month) | dateadd(month, b, a) | a::timestamp+(b | |
| a.AddSeconds(b) | date_add(a, interval b second) | dateadd(second, b, a) | a::timestamp+(b | |
| a.AddTicks(b) | date_add(a, interval b/10 microsecond) | dateadd(millisecond, b / 10000, a) | a::timestamp+(b | |
| a.AddYears(b) | date_add(a, interval b year) | dateadd(year, b, a) | a::timestamp+(b | |
| a.Date | cast(date_format(a, '%Y-%m-%d') as datetime) | convert(char(10),a,120) | a::date | trunc(a) |
| a.Day | dayofmonth(a) | datepart(day, a) | extract(day from a::timestamp) | cast(to_char(a,'DD') as number) |
| a.DayOfWeek | dayofweek(a) | datepart(weekday, a) - 1 | extract(dow from a::timestamp) | case when to_char(a)='7' then 0 else cast(to_char(a) as number) end |
| a.DayOfYear | dayofyear(a) | datepart(dayofyear, a) | extract(doy from a::timestamp) | cast(to_char(a,'DDD') as number) |
| a.Hour | hour(a) | datepart(hour, a) | extract(hour from a::timestamp) | cast(to_char(a,'HH24') as number) |
| a.Millisecond | floor(microsecond(a) / 1000) | datepart(millisecond, a) | extract(milliseconds from a::timestamp)-extract(second from a::timestamp)*1000 | cast(to_char(a,'FF3') as number) |
| a.Minute | minute(a) | datepart(minute, a) | extract(minute from a::timestamp) | cast(to_char(a,'MI') as number) |
| a.Month | month(a) | datepart(month, a) | extract(month from a::timestamp) | cast(to_char(a,'FF3') as number) |
| a.Second | second(a) | datepart(second, a) | extract(second from a::timestamp) | cast(to_char(a,'SS') as number) |
| a.Subtract(b) | timestampdiff(microsecond, b, a) | datediff(millisecond, b, a) * 1000 | (extract(epoch from a::timestamp-b::timestamp)*1000000) | a - b |
| a.Ticks | timestampdiff(microsecond, '0001-1-1', a) * 10 | datediff(millisecond, '1970-1-1', a) * 10000 + 621355968000000000 | extract(epoch from a::timestamp)*10000000+621355968000000000 | cast(to_char(a,'FF7') as number) |
| a.TimeOfDay | timestampdiff(microsecond, date_format(a, '%Y-%m-%d'), a) | '1970-1-1 ' + convert(varchar, a, 14) | extract(epoch from a::time)*1000000 | a - trunc(a) |
| a.Year | year(a) | datepart(year, a) | extract(year from a::timestamp) | 年 |
| a.Equals(b) | a = b | a = b | a = b | a = b |
| a.CompareTo(b) | a - b | a - b | a - b | a - b |
| a.ToString() | date_format(a, '%Y-%m-%d %H:%i:%s.%f') | convert(varchar, a, 121) | to_char(a, 'YYYY-MM-DD HH24:MI:SS.US') | to_char(a,'YYYY-MM-DD HH24:MI:SS.FF6') |
10、时间
| 表达式 | MySql(微秒) | SqlServer(秒) | PostgreSQL(微秒) | Oracle(Interval day(9) to second(7)) |
|---|---|---|---|---|
| TimeSpan.Zero | 0 | 0 | - | 0微秒 |
| TimeSpan.MaxValue | 922337203685477580 | 922337203685477580 | - | numtodsinterval(233720368.5477580,'second') |
| TimeSpan.MinValue | -922337203685477580 | -922337203685477580 | - | numtodsinterval(-233720368.5477580,'second') |
| TimeSpan.Compare(a, b) | a - b | a - b | - | extract(day from (a-b)) |
| TimeSpan.Equals(a, b) | a = b | a = b | - | a = b |
| TimeSpan.FromDays(a) | a * 1000000 * 60 * 60 * 24 | a * 1000000 * 60 * 60 * 24 | - | numtodsinterval(a*86400,'second') |
| TimeSpan.FromHours(a) | a * 1000000 * 60 * 60 | a * 1000000 * 60 * 60 | - | numtodsinterval(a*3600,'second') |
| TimeSpan.FromMilliseconds(a) | a * 1000 | a * 1000 | - | numtodsinterval(a/1000,'second') |
| TimeSpan.FromMinutes(a) | a * 1000000 * 60 | a * 1000000 * 60 | - | numtodsinterval(a*60,'second') |
| TimeSpan.FromSeconds(a) | a * 1000000 | a * 1000000 | - | numtodsinterval(a,'second') |
| TimeSpan.FromTicks(a) | a / 10 | a / 10 | - | numtodsinterval(a/10000000,'second') |
| a.Add(b) | a + b | a + b | - | a + b |
| a.Subtract(b) | a - b | a - b | - | a - b |
| a.CompareTo(b) | a - b | a - b | - | extract(day from (a-b)) |
| a.Days | a div (1000000 * 60 * 60 * 24) | a div (1000000 * 60 * 60 * 24) | - | extract(day from a) |
| a.Hours | a div (1000000 * 60 * 60) mod 24 | a div (1000000 * 60 * 60) mod 24 | - | extract(hour from a) |
| a.Milliseconds | a div 1000 mod 1000 | a div 1000 mod 1000 | - | cast(substr(extract(second from a)-floor(extract(second from a)),2,3) as number) |
| a.Seconds | a div 1000000 mod 60 | a div 1000000 mod 60 | - | extract(second from a) |
| a.Ticks | a * 10 | a * 10 | - | (extract(day from a)86400+extract(hour from a)3600+extract(minute from a)60+extract(second from a))10000000 |
| a.TotalDays | a / (1000000 * 60 * 60 * 24) | a / (1000000 * 60 * 60 * 24) | - | extract(day from a) |
| a.TotalHours | a / (1000000 * 60 * 60) | a / (1000000 * 60 * 60) | - | (extract(day from a)*24+extract(hour from a)) |
| a.TotalMilliseconds | a / 1000 | a / 1000 | - | (extract(day from a)86400+extract(hour from a)3600+extract(minute from a)60+extract(second from a))1000 |
| a.TotalMinutes | a / (1000000 * 60) | a / (1000000 * 60) | - | |
| a.TotalSeconds | a / 1000000 | a / 1000000 | - | (extract(day from a)86400+extract(hour from a)3600+extract(minute from a)*60+extract(second from a)) |
| a.Equals(b) | a = b | a = b | - | a = b |
| a.ToString() | cast(a as varchar) | cast(a as varchar) | - | to_char(a) |
11、数学函数
| 表达式 | MySql | SqlServer | PostgreSQL | Oracle |
|---|---|---|---|---|
| Math.Abs(a) | abs(a) | abs(a) | abs(a) | |
| Math.Acos(a) | acos(a) | acos(a) | acos(a) | acos(a) |
| Math.Asin(a) | asin(a) | asin(a) | asin(a) | asin(a) |
| Math.Atan(a) | atan(a) | atan(a) | atan(a) | atan(a) |
| Math.Atan2(a, b) | atan2(a, b) | atan2(a, b) | atan2(a, b) | - |
| Math.Ceiling(a) | ceiling(a) | ceiling(a) | ceiling(a) | ceil(a) |
| Math.Cos(a) | cos(a) | cos(a) | cos(a) | cos(a) |
| Math.Exp(a) | exp(a) | exp(a) | exp(a) | exp(a) |
| Math.Floor(a) | floor(a) | floor(a) | floor(a) | floor(a) |
| Math.Log(a) | log(a) | log(a) | log(a) | log(e,a) |
| Math.Log10(a) | log10(a) | log10(a) | log10(a) | log(10,a) |
| Math.PI(a) | 3.1415926535897931 | 3.1415926535897931 | 3.1415926535897931 | 3.1415926535897931 |
| Math.Pow(a, b) | pow(a, b) | power(a, b) | pow(a, b) | power(a, b) |
| Math.Round(a, b) | round(a, b) | round(a, b) | round(a, b) | round(a, b) |
| Math.Sign(a) | sign(a) | sign(a) | sign(a) | sign(a) |
| Math.Sin(a) | sin(a) | sin(a) | sin(a) | sin(a) |
| Math.Sqrt(a) | sqrt(a) | sqrt(a) | sqrt(a) | sqrt(a) |
| Math.Tan(a) | tan(a) | tan(a) | tan(a) | tan(a) |
| Math.Truncate(a) | truncate(a, 0) | floor(a) | trunc(a, 0) | trunc(a, 0) |
12、类型转换
| 表达式 | MySql | SqlServer | PostgreSQL | Oracle | Sqlite |
|---|---|---|---|---|---|
| Convert.ToBoolean(a), bool.Parse(a) | a not in ('0','false') | a not in ('0','false') | a::varchar not in ('0','false','f','no') | - | a not in ('0','false') |
| Convert.ToByte(a), byte.Parse(a) | cast(a as unsigned) | cast(a as tinyint) | a::int2 | cast(a as number) | cast(a as int2) |
| Convert.ToChar(a) | substr(cast(a as char),1,1) | substring(cast(a as nvarchar),1,1) | substr(a::char,1,1) | substr(to_char(a),1,1) | substr(cast(a as character),1,1) |
| Convert.ToDateTime(a), DateTime.Parse(a) | cast(a as datetime) | cast(a as datetime) | a::timestamp | to_timestamp(a,'YYYY-MM-DD HH24:MI:SS.FF6') | datetime(a) |
| Convert.ToDecimal(a), decimal.Parse(a) | cast(a as decimal(36,18)) | cast(a as decimal(36,19)) | a::numeric | cast(a as number) | cast(a as decimal(36,18)) |
| Convert.ToDouble(a), double.Parse(a) | cast(a as decimal(32,16)) | cast(a as decimal(32,16)) | a::float8 | cast(a as number) | cast(a as double) |
| Convert.ToInt16(a), short.Parse(a) | cast(a as signed) | cast(a as smallint) | a::int2 | cast(a as number) | cast(a as smallint) |
| Convert.ToInt32(a), int.Parse(a) | cast(a as signed) | cast(a as int) | a::int4 | cast(a as number) | cast(a as smallint) |
| Convert.ToInt64(a), long.Parse(a) | cast(a as signed) | cast(a as bigint) | a::int8 | cast(a as number) | cast(a as smallint) |
| Convert.ToSByte(a), sbyte.Parse(a) | cast(a as signed) | cast(a as tinyint) | a::int2 | cast(a as number) | cast(a as smallint) |
| Convert.ToString(a) | cast(a as decimal(14,7)) | cast(a as decimal(14,7)) | a::float4 | to_char(a) | cast(a as character) |
| Convert.ToSingle(a), float.Parse(a) | cast(a as char) | cast(a as nvarchar) | a::varchar | cast(a as number) | cast(a as smallint) |
| Convert.ToUInt16(a), ushort.Parse(a) | cast(a as unsigned) | cast(a as smallint) | a::int2 | cast(a as number) | cast(a as unsigned) |
| Convert.ToUInt32(a), uint.Parse(a) | cast(a as unsigned) | cast(a as int) | a::int4 | cast(a as number) | cast(a as decimal(10,0)) |
| Convert.ToUInt64(a), ulong.Parse(a) | cast(a as unsigned) | cast(a as bigint) | a::int8 | cast(a as number) | cast(a as decimal(21,0)) |
| Guid.Parse(a) | substr(cast(a as char),1,36) | cast(a as uniqueidentifier) | a::uuid | substr(to_char(a),1,36) | substr(cast(a as character),1,36) |
| Guid.NewGuid() | - | newid() | - | - | - |
| new Random().NextDouble() | rand() | rand() | random() | dbms_random.value | random() |
CodeFirst
| 参数选项 | 说明 |
|---|---|
| IsAutoSyncStructure | 【开发环境必备】自动同步实体结构到数据库，程序运行中检查实体表是否存在，然后创建或修改 |
| IsSyncStructureToLower | 转小写同步结构 |
| IsSyncStructureToUpper | 转大写同步结构，适用 Oracle |
| IsConfigEntityFromDbFirst | 使用数据库的主键和自增，适用 DbFirst 模式，无须在实体类型上设置 [Column(IsPrimary)] 或者 ConfigEntity。此功能目前可用于 mysql/sqlserver/postgresql。 |
| IsNoneCommandParameter | 不使用命令参数化执行，针对 Insert/Update，调试神器 |
| IsLazyLoading | 延时加载导航属性对象，导航属性需要声明 virtual |
1、配置实体（特性）
public class Song {
[Column(IsIdentity = true)]
public int Id { get; set; }
public string Title { get; set; }
public string Url { get; set; }
public virtual ICollection Tags { get; set; }
[Column(IsVersion = true)]
public long versionRow { get; set; }
} 2、在外部配置实体
fsql.CodeFirst
.ConfigEntity(a => {
a.Property(b => b.Id).IsIdentity(true);
a.Property(b => b.versionRow).IsVersion(true);
}); DbFirst
1、获取所有数据库
fsql.DbFirst.GetDatabases();
//返回字符串数组, ["cccddd", "test"]2、获取指定数据库的表信息
fsql.DbFirst.GetTablesByDatabase(fsql.DbFirst.GetDatabases()[0]);
//返回包括表、列详情、主键、唯一键、索引、外键、备注等信息3、生成实体
new FreeSql.Generator.TemplateGenerator()
.Build(fsql.DbFirst,
@"C:\Users\28810\Desktop\github\FreeSql\Templates\MySql\simple-entity",
//模板目录（事先下载）
@"C:\Users\28810\Desktop\你的目录",
//生成后保存的目录
"cccddd"
//数据库
);高级篇
Repository 仓储实现
1、单个仓储
var curd = fsql.GetRepository();
//curd.Find(1);
var item = curd.Get(1);
curd.Update(item);
curd.Insert(item);
curd.Delete(1);
curd.Select.Limit(10).ToList(); 工作单元
using (var uow = fsql.CreateUnitOfWork()) {
var songRepos = uow.GetRepository();
var userRepos = uow.GetRepository();
//上面两个仓储，由同一UnitOfWork uow 创建
//在此执行仓储操作
//这里不受异步方便影响
uow.Commit();
} 局部过滤器 + 数据验证
var topicRepository = fsql.GetGuidRepository(a => a.UserId == 1); 之后在使用 topicRepository 操作方法时：
- 查询/修改/删除时附过滤条件，从而达到不会修改其他用户的数据；
- 添加时，使用过滤条件验证合法性，若不合法则抛出异常；如以下方法就会报错：
topicRepository.Insert(new Topic { UserId = 2 })乐观锁
更新实体数据，在并发情况下极容易造成旧数据将新的记录更新。FreeSql 核心部分已经支持乐观锁。
乐观锁的原理，是利用实体某字段，如：long version，更新前先查询数据，此时 version 为 1，更新时产生的 SQL 会附加 where version = 1，当修改失败时（即 Affrows == 0）抛出异常。
每个实体只支持一个乐观锁，在属性前标记特性：[Column(IsVersion = true)] 即可。
无论是使用 FreeSql/FreeSql.Repository/FreeSql.DbContext，每次更新 version 的值都会增加 1
DbContext
dotnet add package FreeSql.DbContext
实现类似 EFCore 使用方法，跟踪对象状态，最终通过 SaveChanges 方法以事务的方式提交整段操作。
using (var ctx = new SongContext()) {
var song = new Song { BigNumber = "1000000000000000000" };
ctx.Songs.Add(song);
song.BigNumber = (BigInteger.Parse(song.BigNumber) + 1).ToString();
ctx.Songs.Update(song);
var tag = new Tag {
Name = "testaddsublist",
Tags = new[] {
new Tag { Name = "sub1" },
new Tag { Name = "sub2" },
new Tag {
Name = "sub3",
Tags = new[] {
new Tag { Name = "sub3_01" }
}
}
}
};
ctx.Tags.Add(tag);
ctx.SaveChanges();
}
public class Song {
[Column(IsIdentity = true)]
public int Id { get; set; }
public string BigNumber { get; set; }
[Column(IsVersion = true)] //乐观锁
public long versionRow { get; set; }
}
public class Tag {
[Column(IsIdentity = true)]
public int Id { get; set; }
public int? Parent_id { get; set; }
public virtual Tag Parent { get; set; }
public string Name { get; set; }
public virtual ICollection Tags { get; set; }
}
public class SongContext : DbContext {
public DbSet Songs { get; set; }
public DbSet Tags { get; set; }
protected override void OnConfiguring(DbContextOptionsBuilder builder) {
builder.UseFreeSql(fsql);
}
} 导航属性
支持 1对1、1对多、多对1、多对多 的约定导航属性配置，主要用于表达式内部查询；
//OneToOne、ManyToOne
var t0 = fsql.Select().Where(a => a.Parent.Parent.Name == "粤语").ToList();
//OneToMany
var t1 = fsql.Select().Where(a => a.Tags.AsSelect().Any(t => t.Parent.Id == 10)).ToList();
//ManyToMany
var t2 = fsql.Select().Where(s => s.Tags.AsSelect().Any(t => t.Name == "国语")).ToList(); 不朽篇
读写分离
数据库读写分离，本功能是客户端的读写分离行为，数据库服务器该怎么配置仍然那样配置，不受本功能影响，为了方便描术后面讲到的【读写分离】都是指客户端的功能支持。
各种数据库的读写方案不一，数据库端开启读写分离功能后，读写分离的实现大致分为以下几种：
1、nginx代理，配置繁琐且容易出错；
2、中件间，如MyCat，MySql可以其他数据库怎么办？
3、在client端支持；
FreeSql 实现了第3种方案，支持一个【主库】多个【从库】，【从库】的查询策略为随机方式。
若某【从库】发生故障，将切换到其他可用【从库】，若已全部不可用则使用【主库】查询。
出现故障【从库】被隔离起来间隔性的检查可用状态，以待恢复。
IFreeSql fsql = new FreeSql.FreeSqlBuilder()
.UseConnectionString(FreeSql.DataType.MySql, connstr)
.UseSlave("connectionString1", "connectionString2")
//使用从数据库，支持多个
.Build();
select.Where(a => a.Id == 1).ToOne();
//读【从库】（默认）
select.Master().WhereId(a => a.Id == 1).ToOne();
//强制读【主库】下面是以前某项目的测试图片，以供参考，整个过程无感切换和恢复：
分区分表
FreeSql 提供 AsTable 分表的基础方法，GuidRepository 作为分存式仓储将实现了分表与分库（不支持跨服务器分库）的封装。
var logRepository = fsql.GetGuidRepository(null, oldname => $"{oldname}_{DateTime.Now.ToString("YYYYMM")}"); 上面我们得到一个日志仓储按年月分表，使用它 CURD 最终会操作 Log_201903 表。
合并两个仓储，实现分表下的联表查询：
fsql.GetGuidRepository().Select.FromRepository(logRepository)
.LeftJoin(b => b.UserId == a.Id)
.ToList(); 租户
1、按租户字段区分
FreeSql.Repository 现实了 filter（过滤与验证）功能，如：
var topicRepos = fsql.GetGuidRepository(t => t.TerantId == 1); 使用 topicRepos 对象进行 CURD 方法：
- 在查询/修改/删除时附加此条件，从而达到不会修改 TerantId != 1 的数据；
- 在添加时，使用表达式验证数据的合法性，若不合法则抛出异常；
利用这个功能，我们可以很方便的实现数据分区，达到租户的目的。
2、按租户分表
FreeSql.Repository 现实了 分表功能，如：
var tenantId = 1;
var reposTopic = orm.GetGuidRepository(null, oldname => $"{oldname}{tenantId}"); 上面我们得到一个仓储按租户分表，使用它 CURD 最终会操作 Topic_1 表。
3、按租户分库
与方案二相同，只是表存储的位置不同。
4、全局设置
通过注入的方式设置仓储类的全局过滤器。
public void ConfigureServices(IServiceCollection services) {
services.AddMvc();
services.AddSingleton(Fsql);
services.AddFreeRepository(filter => {
var tenantId = 求出当前租户id;
filter
.Apply("softdelete", a => a.IsDeleted == false)
.Apply("tenant", a => a.TenantId == tenantId)
}, this.GetType().Assembly
);
} 结束语
这次全方位介绍 FreeSql 的功能，只抽取了重要内容发布，由于功能实在太多不方便在一篇文章介绍祥尽。
我个人是非常想展开编写，将每个功能的设计和实现放大来介绍，但还是先希望得到更多人的关注，不然就是一台独角戏了。
gayhub: https://github.com/2881099/FreeSql，肯请献上宝贵的一星，谢谢！