एक डेटाबेस से जुड़ना //Connecting to a Database

import (
  "gorm.io/driver/mysql"
  "gorm.io/gorm"
)

func main() {
  // refer https://github.com/go-sql-driver/mysql#dsn-data-source-name for details
  dsn := "user:pass@tcp(127.0.0.1:3306)/dbname?charset=utf8mb4&parseTime=True&loc=Local"
  db, err := gorm.Open(mysql.Open(dsn), &gorm.Config{})
}

db, err := gorm.Open(mysql.New(mysql.Config{
  DSN: "gorm:gorm@tcp(127.0.0.1:3306)/gorm?charset=utf8&parseTime=True&loc=Local", // data source name //डेटा स्रोत का नाम
  DefaultStringSize: 256, // default size for string fields //स्ट्रिंग फ़ील्ड के लिए डिफ़ॉल्ट आकार
  DisableDatetimePrecision: true, // disable datetime precision, which not supported before MySQL 5.6 /डेटाटाइम परिशुद्धता अक्षम करें, जो MySQL 5.6 से पहले समर्थित नहीं है
  DontSupportRenameIndex: true, // drop & create when rename index, rename index not supported before MySQL 5.7, MariaDB //
निर्दिष्ट का नाम बदलने पर बनाएँ, MySQL 5.7, MariaDB से पहले संगति का नाम परिवर्तन नहीं होता है
  DontSupportRenameColumn: true, // `change` when rename column, rename column not supported before MySQL 8, MariaDB 
// // `परिवर्तन` जब स्तंभ का नाम बदलें, नाम बदलें कॉलम MySQL 8, MariaDB से पहले समर्थित नहीं है
  SkipInitializeWithVersion: false, // auto configure based on currently MySQL version //वर्तमान में MySQL संस्करण के आधार पर ऑटो कॉन्फ़िगर करें
}), &gorm.Config{})

import (
  _ "example.com/my_mysql_driver"
  "gorm.io/driver/mysql"
  "gorm.io/gorm"
)

db, err := gorm.Open(mysql.New(mysql.Config{
  DriverName: "my_mysql_driver",
  DSN: "gorm:gorm@tcp(localhost:9910)/gorm?charset=utf8&parseTime=True&loc=Local", // data source name, refer https://github.com/go-sql-driver/mysql#dsn-data-source-name
}), &gorm.Config{})

import (
  "database/sql"
  "gorm.io/driver/mysql"
  "gorm.io/gorm"
)

sqlDB, err := sql.Open("mysql", "mydb_dsn")
gormDB, err := gorm.Open(mysql.New(mysql.Config{
  Conn: sqlDB,
}), &gorm.Config{})

import (
  "gorm.io/driver/postgres"
  "gorm.io/gorm"
)

dsn := "host=localhost user=gorm password=gorm dbname=gorm port=9920 sslmode=disable TimeZone=Asia/Shanghai"
db, err := gorm.Open(postgres.Open(dsn), &gorm.Config{})

// https://github.com/go-gorm/postgres
db, err := gorm.Open(postgres.New(postgres.Config{
  DSN: "user=gorm password=gorm dbname=gorm port=9920 sslmode=disable TimeZone=Asia/Shanghai",
  PreferSimpleProtocol: true, // disables implicit prepared statement usage
}), &gorm.Config{})

import (
  _ "github.com/GoogleCloudPlatform/cloudsql-proxy/proxy/dialers/postgres"
  "gorm.io/gorm"
)

db, err := gorm.Open(postgres.New(postgres.Config{
  DriverName: "cloudsqlpostgres",
  DSN: "host=project:region:instance user=postgres dbname=postgres password=password sslmode=disable",
})

import (
  "database/sql"
  "gorm.io/driver/postgres"
  "gorm.io/gorm"
)

sqlDB, err := sql.Open("pgx", "mydb_dsn")
gormDB, err := gorm.Open(postgres.New(postgres.Config{
  Conn: sqlDB,
}), &gorm.Config{})

import (
  "gorm.io/driver/gaussdb"
  "gorm.io/gorm"
)

dsn := "host=localhost user=gorm password=gorm dbname=gorm port=8000 sslmode=disable TimeZone=Asia/Shanghai"
db, err := gorm.Open(gaussdb.Open(dsn), &gorm.Config{})

// https://github.com/go-gorm/gaussdb
db, err := gorm.Open(gaussdb.New(gaussdb.Config{
  DSN: "user=gorm password=gorm dbname=gorm port=8000 sslmode=disable TimeZone=Asia/Shanghai",
  PreferSimpleProtocol: true, // disables implicit prepared statement usage
}), &gorm.Config{})

import (
  _ "github.com/GoogleCloudPlatform/cloudsql-proxy/proxy/dialers/gaussdb"
  "gorm.io/gorm"
)

db, err := gorm.Open(gaussdb.New(gaussdb.Config{
  DriverName: "cloudsqlgaussdb",
  DSN: "host=project:region:instance user=gaussdb dbname=gaussdb password=password sslmode=disable",
})

import (
  "database/sql"
  "gorm.io/driver/gaussdb"
  "gorm.io/gorm"
)

sqlDB, err := sql.Open("gaussdbgo", "mydb_dsn")
gormDB, err := gorm.Open(gaussdb.New(gaussdb.Config{
  Conn: sqlDB,
}), &gorm.Config{})

dataSourceName := `user="scott" password="tiger" 
                   connectString="dbhost:1521/orclpdb1"
                   libDir="/Path/to/your/instantclient_23_26"`

dataSourceName := `user="scott" password="tiger" 
                   connectString="dbhost:1521/orclpdb1"`

import (
  "github.com/oracle-samples/gorm-oracle/oracle"
  "gorm.io/gorm"
)

dataSourceName := `user="scott" password="tiger"
                   connectString="dbhost:1521/orclpdb1"`
db, err := gorm.Open(oracle.Open(dataSourceName), &gorm.Config{})

import (
  "gorm.io/driver/sqlite" // Sqlite driver based on CGO
  // "github.com/glebarez/sqlite" // Pure-Go SQLite driver, checkout https://github.com/glebarez/sqlite for details
  // "github.com/libtnb/sqlite" // Pure-Go SQLite driver, checkout https://github.com/libtnb/sqlite for details
  "gorm.io/gorm"
)

// github.com/mattn/go-sqlite3
db, err := gorm.Open(sqlite.Open("gorm.db"), &gorm.Config{})

import (
  "gorm.io/driver/sqlserver"
  "gorm.io/gorm"
)

// github.com/denisenkom/go-mssqldb
dsn := "sqlserver://gorm:LoremIpsum86@localhost:9930?database=gorm"
db, err := gorm.Open(sqlserver.Open(dsn), &gorm.Config{})

import (
  "fmt"
  "gorm.io/driver/mysql"
  "gorm.io/gorm"
)

type Product struct {
  ID    uint `gorm:"primaryKey;default:auto_random()"`
  Code  string
  Price uint
}

func main() {
  db, err := gorm.Open(mysql.Open("root:@tcp(127.0.0.1:4000)/test"), &gorm.Config{})
  if err != nil {
    panic("failed to connect database")
  }

  db.AutoMigrate(&Product{})

  insertProduct := &Product{Code: "D42", Price: 100}

  db.Create(insertProduct)
  fmt.Printf("insert ID: %d, Code: %s, Price: %d\n",
    insertProduct.ID, insertProduct.Code, insertProduct.Price)

  readProduct := &Product{}
  db.First(&readProduct, "code = ?", "D42") // find product with code D42

  fmt.Printf("read ID: %d, Code: %s, Price: %d\n",
    readProduct.ID, readProduct.Code, readProduct.Price)
}

import (
  "gorm.io/driver/clickhouse"
  "gorm.io/gorm"
)

func main() {
  dsn := "tcp://localhost:9000?database=gorm&username=gorm&password=gorm&read_timeout=10&write_timeout=20"
  db, err := gorm.Open(clickhouse.Open(dsn), &gorm.Config{})

  // Auto Migrate
  db.AutoMigrate(&User{})
  // Set table options
  db.Set("gorm:table_options", "ENGINE=Distributed(cluster, default, hits)").AutoMigrate(&User{})

  // Insert
  db.Create(&user)

  // Select
  db.Find(&user, "id = ?", 10)

  // Batch Insert
  var users = []User{user1, user2, user3}
  db.Create(&users)
  // ...
}

sqlDB, err := db.DB()

//SetMaxIdleConns idle कनेक्शन पूल में अधिकतम संख्या में कनेक्शन सेट करता है।
sqlDB.SetMaxIdleConns(10)

//SetMaxOpenConns डेटाबेस के लिए खुले कनेक्शन की अधिकतम संख्या सेट करता है।
sqlDB.SetMaxOpenConns(100

// SetConnMaxLifetime एक कनेक्शन के पुन: उपयोग किए जा सकने वाले अधिकतम समय को सेट करता है।
sqlDB.SetConnMaxLifetime(time.Hour)