static async Task RemoveDbAsync()
{
using (var ctx = new NameAgeContext())
{
bool deleted = await ctx.Database.EnsureDeletedAsync();
string deletion = deleted ? "deleted" : "non-existence";
Console.WriteLine($"database deletion: {deletion}");
}
}
static async Task NewDbAsync()
{
using (var ctx = new NameAgeContext())
{
bool created = await ctx.Database.EnsureCreatedAsync();
string creation = created ? "created" : "exists";
Console.WriteLine($"database creation: {creation}");
}
}
// await NewDbAsync();// 当表不存在的时候，可以重新建表。
// await RemoveDbAsync();
// alter table nameage drop constraint PK_NameAge
// set IDENTITY_INSERT NameAge ON
// await AddRecordAsync("efcore11", 23); // TODO, no record inserted.
static async Task QueryUpdateDeleteBooks()
{
using (var ctx = new NameAgeContext())
{
// tested
List <NameAge> list = await ctx.DbRows.ToListAsync();
foreach (var na in list)
{
Console.WriteLine($"{na.NameAgeId}, {na.Name}, {na.Age}");
}
Console.WriteLine();
// tested
List <NameAge> list2 = await ctx.DbRows
.Where(r => r.Name == "duke").ToListAsync();
foreach (var na in list2)
{
Console.WriteLine($"{na.NameAgeId}, {na.Name}, {na.Age}");
}
// tested
NameAge record = await ctx.DbRows
.Where(r => r.Name == "selves").FirstOrDefaultAsync();
if (record != null)
{
record.Age += 1;
// record.Name = "selves";
int c = await ctx.SaveChangesAsync(); // update statement
Console.WriteLine($"{c} records updated");
}
// tested
var toRemove = await ctx.DbRows
.Where(r => r.Name == "myname").ToListAsync();
ctx.DbRows?.RemoveRange(toRemove);
int count = await ctx.SaveChangesAsync();
Console.WriteLine($"{count} records deleted");
}
// QueryUpdateDeleteBooks();
}
public static async Task AddRecordAsync(string name, int age)
{
using (var ctx = new NameAgeContext())
{
using (var tx = ctx.Database.BeginTransaction())
{
// ctx.Database.ExecuteSqlRaw("SET IDENTITY_INSERT dbo.NameAge ON");
// ctx.Database.ExecuteSqlRaw("SET IDENTITY_INSERT dbo.NameAge OFF");
var nameAge = new NameAge {
Name = name, Age = age
};
/*await*/ ctx.DbRows?.Add(nameAge);
int rows = await ctx.SaveChangesAsync();
// ctx.Database.ExecuteSqlRaw("SET IDENTITY_INSERT dbo.NameAge OFF");
Console.WriteLine($"{rows} row(s) inserted");
tx.Commit();
}
}
}