After I try to insert a row into database and it fails due to duplicate (not primary key collision - another key), how do I get the primary key of the colliding row that prevented the insert?
Example:
The table:
CREATE TABLE `my_table` (
`id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`unique_value` varchar(60) NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `unique_data` (`unique_values`),
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
Some initial data:
INSERT INTO `my_table`(`unique_value`) VALUES ('unique string 1');
INSERT INTO `my_table`(`unique_value`) VALUES ('unique string 2');
And now, this will fail because of the collision in the index:
MySqlConnection conn = new MySqlConnection(connString);
conn.Open();
MySqlCommand comm = conn.CreateCommand();
comm.CommandText = "INSERT INTO `my_table`(`unique_value`) VALUES 'unique string 2'";
comm.ExecuteNonQuery();
conn.Close();
Can I get the primary key of the colliding row without making another query?
while creating the table you can use "Identity" keyword which will do all the "not null and Auto Increment" Stuff.
But this is for MsSQL
Try this:
create table my_table
(
ID int Primary key identity,
unique_value varchar(60) NOT NULL
)
As you said this that you are not worry about PK hence you can check the value of the column which has unique index.If there is already a raw with the value that you passing in new row then you are trying to insert duplicate otherwise not.
Related
I have the following simple SQLite script to create a new database with a versioning table:
BEGIN TRANSACTION;
CREATE TABLE IF NOT EXISTS `db_versions` (
`version` integer NOT NULL PRIMARY KEY AUTOINCREMENT UNIQUE,
`name` varchar ( 50 ) DEFAULT NULL UNIQUE,
`date_defined` datetime DEFAULT NULL,
`comments` text
);
INSERT INTO `db_versions` VALUES (0,'initial-create','2017-12-02 14:41:56',NULL);
COMMIT;
Running this script in the DB Browser for SQLite logs correctly logs that only 1 row is affected (inserted). However, when I try to execute this script in code with Mono (Mono.Data.Sqlite), the script apparently affects 2 rows. Here is that code:
using (var conn = new SqliteConnection(_connStr)) {
await conn.OpenAsync(cancellationToken);
using (SqliteCommand comm = conn.CreateCommand()) {
comm.CommandType = CommandType.Text;
comm.CommandText = #"
BEGIN TRANSACTION;
CREATE TABLE IF NOT EXISTS `db_versions` (
`version` integer NOT NULL PRIMARY KEY AUTOINCREMENT UNIQUE,
`name` varchar ( 50 ) DEFAULT NULL UNIQUE,
`date_defined` datetime DEFAULT NULL,
`comments` text
);
INSERT INTO `db_versions` VALUES (0,'initial-create','2017-12-02 14:41:56',NULL);
COMMIT;
";
int rowsAffected = await comm.ExecuteNonQueryAsync(cancellationToken);
if (rowsAffected > 1) {
// Why is this code running??
}
}
}
Does anyone know why I'm getting these different results?
Gah, I figured it out. The integer version field was being defined AUTOINCREMENT, which also adds the largest ROWID to an internal sqlite_sequence table. So there was a 2nd row being added.
I'm developing a WinForm desktop application for users to input employees retirement data, using SQL Server 2008 as DB.
One of the tables that gets part of the user data has a reference to another table whose records were defined at design time, adding a Foreign Key constraint for consistency.
CREATE TABLE tbCongedo (
ID int IDENTITY(0,1) PRIMARY KEY,
ID_ANAGRAFICA int NOT NULL,
ID_TIPOLOGIA int NOT NULL,
DECORRENZA datetime NOT NULL,
PROT_NUM nvarchar(7) NOT NULL,
PROT_DATA datetime NOT NULL
);
CREATE TABLE tbTipologia (
ID int IDENTITY(0,1) PRIMARY KEY,
TIPOLOGIA nvarchar(20)
);
INSERT INTO tbTipologia VALUES ('CONGEDO'), ('POSTICIPO'), ('ANTICIPO'), ('REVOCA'), ('DECESSO')
ALTER TABLE tbCongedo
ADD CONSTRAINT FK_tbCongedo_tbTipologia
FOREIGN KEY (ID_TIPOLOGIA) REFERENCES tbTipologia(ID)
Then, I have this code that should execute the INSERT statement
public int Insert(SqlConnection Connessione)
{
using (SqlCommand Comando = new SqlCommand("INSERT INTO tbCongedo VALUES (#ID_ANAGRAFICA, #PROT_NUM, #PROT_DATA, #DECORRENZA, #ID_TIPOLOGIA); SELECT SCOPE_IDENTITY()", Connessione))
{
Comando.Parameters.AddWithValue("#ID_ANAGRAFICA", ID_ANAGRAFICA);
Comando.Parameters.AddWithValue("#PROT_NUM", PROT_NUM);
Comando.Parameters.AddWithValue("#PROT_DATA", PROT_DATA);
Comando.Parameters.AddWithValue("#DECORRENZA", DECORRENZA);
Comando.Parameters.AddWithValue("#ID_TIPOLOGIA", ID_TIPOLOGIA);
ID = Int32.Parse(Comando.ExecuteScalar().ToString());
}
return ID;
}
but I'm given this SqlException:
The INSERT statement conflicted with the FOREIGN KEY constraint "FK_tbCongedo_tbTipologia". The conflict occurred in database "Scadenziario_ver4_TEST", table "dbo.tbTipologia", column 'ID'
These are the data that I was trying to get inserted in the table:
ID_ANAGRAFICA = 2
ID_TIPOLOGIA = 0
PROT_DATA = {16/03/2018 00:00:00}
DECORRENZA = {16/03/2018 00:00:00}
PROT_NUM = 123456
Funny thing is that when I try to insert those same data manually through SQL Server Management Studio, I'm given no error at all.
Thanks.-
Try specifying fields: (col_name1, col_name2, ...).
Without that the VALUES may not be applied as how you might hope. Variable names are NOT automagically matched with similarly-named columns.
So like this:
... new SqlCommand
(
"INSERT INTO tbCongedo " +
" (ID_ANAGRAFICA, PROT_NUM, PROT_DATA, DECORRENZA, ID_TIPOLOGIA) "
"VALUES (#ID_ANAGRAFICA, #PROT_NUM, #PROT_DATA, #DECORRENZA, #ID_TIPOLOGIA); " +
"SELECT SCOPE_IDENTITY()", Connessione
)
...
I think the problem isn't in the data but in the INSERT statement itself. You are trying to insert the values to the wrong columns using the wrong order. To solve the issue you should either specify the columns in the INSERT statement or correct the order of the values. In your case the query will try to insert the value of #PROT_NUM in the ID_TIPOLOGIA instead.
I want to create insert and update sql statements in single statement. But insert statement is for one table and update statement for another table...
this is Appliance_Location table
CREATE TABLE [dbo].[Appliance_Location] (
[Appliance_Id] NCHAR (10) NOT NULL,
[RoomId] NVARCHAR (20) NOT NULL,
[ApplianceName] NCHAR (10) NOT NULL,
[AddDate] DATE NULL,
CONSTRAINT [PK_Appliance_Location] PRIMARY KEY CLUSTERED ([Appliance_Id] ASC)
);
and this is Appliance_Count table
CREATE TABLE [dbo].[Appliance_Count] (
[RoomId] NVARCHAR (20) NOT NULL,`enter code here`
[Bulb] INT NOT NULL,
[Fan] INT NOT NULL,
[AC] INT NOT NULL,
[Computer] INT NOT NULL,
CONSTRAINT [PK_Appliance_Count] PRIMARY KEY CLUSTERED ([RoomId] ASC)
);
when I insert an appliance to the Appliance_Location table then count of that particular appliance in Appliance_Count table should be updated
It is not possible to insert and update in single query. But You have one option for this task. You can create trigger to inserting of one table. And trigger through update value in other table.
Not sure how about other SQL servers, but you are allowed to execute multiple queries using the same syntax in MS SQL.
using (SqlConnection connection = CreateConnection())
{
SqlCommand command = connection.CreateCommand();
command.CommandText = #"INSERT INTO `TableA` VALUES (1, 2, 3);
UPDATE `TableB` SET [Val] = 'value' WHERE [Id] > 10";
command.CommandType = CommandType.Text;
// ... other initializations
return command.ExecuteNonQuery();
}
You even can return values:
INSERT INTO `TableC` VALUES (1, 'value');
SELECT SCOPE_IDENTITY() AS Id;
After this query you can get SQL reader and read "Id" value from the response.
Why don't you just try before asking?
I have a database connection where i insert data into the table having 2 columns i.e. id,first_name,last_name.
Following is the code:
private void Insert_Click(object sender, EventArgs e)
{
try
{
String query = "INSERT INTO data_table (first_name,last_name) VALUES (#f_name,#l_name)";
using (SqlConnection connection1 = new SqlConnection(
Properties.Settings.Default.DatabaseConnection))
using (SqlCommand insertCommand = new SqlCommand(query, connection1))
{
//a shorter syntax to adding parameters
// insertCommand.Parameters.Add("#id", SqlDbType.Int).Value = 1;
insertCommand.Parameters.Add("#f_name", SqlDbType.NChar).Value = "JAVED";
insertCommand.Parameters.Add("#l_name", SqlDbType.NChar).Value = "GHAMJN";
//make sure you open and close(after executing) the connection
connection1.Open();
insertCommand.ExecuteNonQuery();
connection1.Close();
MessageBox.Show("Record inserted. Please check your table data. :)");
}
}
catch (Exception err)
{
MessageBox.Show(err.Message);
}
}
Following is T-SQL script:
CREATE TABLE [dbo].[data_table] (
[Id] INT NOT NULL IDENTITY,
[first_name] NCHAR (10) NULL,
[last_name] NCHAR (10) NULL,
PRIMARY KEY CLUSTERED ([Id] ASC)
);
The issue is created by id: I have set it auto-increment.
When i click insert button a MessageBox pops saying:
Cannot insert the value NULL into column 'Id',table 'C:\Users.......\Database1.MDF.dbo.data_table;column doesn't allows null.INSERT fails
Add identity seed and increment values to your table...
CREATE TABLE [dbo].[data_table] (
[Id] INT NOT NULL IDENTITY(1,1),
[first_name] NCHAR (10) NULL,
[last_name] NCHAR (10) NULL,
PRIMARY KEY CLUSTERED ([Id] ASC)
);
Your Id field should be modified as shown below
Deleting that table alongwith all the old copies of old table and creating a new table with suggested Identity(1,1) resolved the issue
try this. The behaviour of Identity Columns can be selectively enabled or disabled with this statement.
If your Identity Column is configured correctly, then this is the only logical explanation for it not behaving as expected
SET IDENTITY_INSERT [dbo].[data_table] ON;
However, it is more likely that your assertion of correctness is flawed and you have not configured the Identity Column correctly.
This question already has answers here:
Is there AUTO INCREMENT in SQLite?
(9 answers)
Closed last month.
I'm new to SQLite and I'm trying to run the following code:
using (var cn = new SQLiteConnection("Data Source=:memory:;Version=3;")) {
cn.Open();
var cmd = cn.CreateCommand();
cmd.CommandText = "CREATE TABLE [ContentItems] ([Id] [int] IDENTITY(1,1) NOT NULL, [Title] [nvarchar](100) NOT NULL, CONSTRAINT [PK_ContentItems] PRIMARY KEY ([Id]))";
cmd.ExecuteNonQuery();
var cmd2 = cn.CreateCommand();
cmd2.CommandText = "INSERT INTO [ContentItems] (Title) VALUES ('Test 1')";
cmd2.ExecuteNonQuery();
}
But this gives the error:
Abort due to constraint violation ContentItems.Id may not be NULL
I've had a look through the documentation but based on my past SQL experience I cannot see why this doesn't work. I'd appreciate the help. Thanks
SQLite creates what you're thinking of as an IDENTITY column using the AUTOINCREMENT keyword. In your example, the ID column is not created with AUTOINCREMENT and, since it is declared NOT NULL, you must supply a value.
The CREATE statement you're after is:
CREATE TABLE [ContentItems] (
[Id] INTEGER AUTOINCREMENT NOT NULL,
[Title] TEXT NOT NULL,
CONSTRAINT [PK_ContentItems] PRIMARY KEY ([Id])
)
Note that SQLite uses the TEXT data type (although it will map anything containing "CHAR" to that datatype) and doesn't need or respect maximum field lengths.