Support Oracle dialect (#995)

* feat: support Oracle dialect

* feat: update README.md

README.md

@@ -1,4 +1,4 @@
-# SQL-first Golang ORM for PostgreSQL, MySQL, MSSQL, and SQLite
+# SQL-first Golang ORM for PostgreSQL, MySQL, MSSQL, SQLite and Oracle
 
 [![build workflow](https://github.com/uptrace/bun/actions/workflows/build.yml/badge.svg)](https://github.com/uptrace/bun/actions)
 [![PkgGoDev](https://pkg.go.dev/badge/github.com/uptrace/bun)](https://pkg.go.dev/github.com/uptrace/bun)
@@ -19,6 +19,7 @@
   [MySQL](https://bun.uptrace.dev/guide/drivers.html#mysql) (including MariaDB),
   [MSSQL](https://bun.uptrace.dev/guide/drivers.html#mssql),
   [SQLite](https://bun.uptrace.dev/guide/drivers.html#sqlite).
+  [Oracle](https://bun.uptrace.dev/guide/drivers.html#oracle).
 - [ORM-like](/example/basic/) experience using good old SQL. Bun supports structs, map, scalars, and
   slices of map/structs/scalars.
 - [Bulk inserts](https://bun.uptrace.dev/guide/query-insert.html).

dialect/dialect.go

@@ -12,6 +12,8 @@ func (n Name) String() string {
 		return "mysql"
 	case MSSQL:
 		return "mssql"
+	case Oracle:
+		return "oracle"
 	default:
 		return "invalid"
 	}
@@ -23,4 +25,5 @@ const (
 	SQLite
 	MySQL
 	MSSQL
+	Oracle
 )

dialect/oracledialect/dialect.go

@@ -0,0 +1,126 @@
+package oracledialect
+
+import (
+	"database/sql"
+	"encoding/hex"
+	"fmt"
+	"time"
+
+	"github.com/uptrace/bun"
+	"github.com/uptrace/bun/dialect"
+	"github.com/uptrace/bun/dialect/feature"
+	"github.com/uptrace/bun/dialect/sqltype"
+	"github.com/uptrace/bun/schema"
+)
+
+func init() {
+	if Version() != bun.Version() {
+		panic(fmt.Errorf("oracledialect and Bun must have the same version: v%s != v%s",
+			Version(), bun.Version()))
+	}
+}
+
+type Dialect struct {
+	schema.BaseDialect
+
+	tables   *schema.Tables
+	features feature.Feature
+}
+
+func New() *Dialect {
+	d := new(Dialect)
+	d.tables = schema.NewTables(d)
+	d.features = feature.CTE |
+		feature.WithValues |
+		feature.Returning |
+		//feature.InsertReturning | // TODO
+		//feature.Output | // TODO
+		feature.InsertOnConflict |
+		//feature.TableNotExists |
+		feature.SelectExists |
+		feature.AutoIncrement |
+		feature.CompositeIn
+	return d
+}
+
+func (d *Dialect) Init(*sql.DB) {}
+
+func (d *Dialect) Name() dialect.Name {
+	return dialect.Oracle
+}
+
+func (d *Dialect) Features() feature.Feature {
+	return d.features
+}
+
+func (d *Dialect) Tables() *schema.Tables {
+	return d.tables
+}
+
+func (d *Dialect) OnTable(table *schema.Table) {
+	for _, field := range table.FieldMap {
+		d.onField(field)
+	}
+}
+
+func (d *Dialect) onField(field *schema.Field) {
+	field.DiscoveredSQLType = fieldSQLType(field)
+}
+
+func (d *Dialect) IdentQuote() byte {
+	return '"'
+}
+
+func (*Dialect) AppendBytes(b, bs []byte) []byte {
+	if bs == nil {
+		return dialect.AppendNull(b)
+	}
+
+	b = append(b, "0x"...)
+
+	s := len(b)
+	b = append(b, make([]byte, hex.EncodedLen(len(bs)))...)
+	hex.Encode(b[s:], bs)
+
+	return b
+}
+
+func (d *Dialect) DefaultVarcharLen() int {
+	return 255
+}
+
+func (d *Dialect) AppendSequence(b []byte, table *schema.Table, field *schema.Field) []byte {
+	return append(b, " GENERATED BY DEFAULT AS IDENTITY"...)
+}
+
+func fieldSQLType(field *schema.Field) string {
+	switch field.DiscoveredSQLType {
+	case sqltype.SmallInt, sqltype.BigInt:
+		// INTEGER PRIMARY KEY is an alias for the ROWID.
+		// It is safe to convert all ints to INTEGER, because SQLite types don't have size.
+		return sqltype.Integer
+	case sqltype.Boolean:
+		return "number(1,0)"
+	default:
+		return field.DiscoveredSQLType
+	}
+}
+
+func (*Dialect) AppendTime(b []byte, tm time.Time) []byte {
+	if tm.IsZero() {
+		b = append(b, "NULL"...)
+		return b
+	}
+	b = append(b, "TO_TIMESTAMP('"...)
+	b = tm.AppendFormat(b, "2006-01-02 15:04:05.999999")
+	b = append(b, "', 'YYYY-MM-DD HH24:MI:SS.FF')"...)
+	return b
+}
+
+func (*Dialect) AppendBool(b []byte, v bool) []byte {
+	if v {
+		return append(b, '1')
+	}
+
+	return append(b, '0')
+}

dialect/oracledialect/scan.go

@@ -0,0 +1,11 @@
+package oracledialect
+
+import (
+	"reflect"
+
+	"github.com/uptrace/bun/schema"
+)
+
+func scanner(typ reflect.Type) schema.ScannerFunc {
+	return schema.Scanner(typ)
+}

dialect/oracledialect/version.go

@@ -0,0 +1,6 @@
+package oracledialect
+
+// Version is the current release version.
+func Version() string {
+	return "1.2.1"
+}

query_base.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"time"
 
+	"github.com/uptrace/bun/dialect"
 	"github.com/uptrace/bun/dialect/feature"
 	"github.com/uptrace/bun/internal"
 	"github.com/uptrace/bun/schema"
@@ -418,7 +419,11 @@ func (q *baseQuery) _appendTables(
 		} else {
 			b = fmter.AppendQuery(b, string(q.table.SQLNameForSelects))
 			if withAlias && q.table.SQLAlias != q.table.SQLNameForSelects {
-				b = append(b, " AS "...)
+				if q.db.dialect.Name() == dialect.Oracle {
+					b = append(b, ' ')
+				} else {
+					b = append(b, " AS "...)
+				}
 				b = append(b, q.table.SQLAlias...)
 			}
 		}

query_table_create.go

@@ -9,6 +9,7 @@ import (
 	"strconv"
 	"strings"
 
+	"github.com/uptrace/bun/dialect"
 	"github.com/uptrace/bun/dialect/feature"
 	"github.com/uptrace/bun/dialect/sqltype"
 	"github.com/uptrace/bun/internal"
@@ -165,7 +166,7 @@ func (q *CreateTableQuery) AppendQuery(fmter schema.Formatter, b []byte) (_ []by
 		b = append(b, field.SQLName...)
 		b = append(b, " "...)
 		b = q.appendSQLType(b, field)
-		if field.NotNull {
+		if field.NotNull && q.db.dialect.Name() != dialect.Oracle {
 			b = append(b, " NOT NULL"...)
 		}
 
@@ -246,7 +247,11 @@ func (q *CreateTableQuery) appendSQLType(b []byte, field *schema.Field) []byte {
 		return append(b, field.CreateTableSQLType...)
 	}
 
-	b = append(b, sqltype.VarChar...)
+	if q.db.dialect.Name() == dialect.Oracle {
+		b = append(b, "VARCHAR2"...)
+	} else {
+		b = append(b, sqltype.VarChar...)
+	}
 	b = append(b, "("...)
 	b = strconv.AppendInt(b, int64(q.varchar), 10)
 	b = append(b, ")"...)