Initial commit

Author: gernest

dialect.go

@@ -0,0 +1,159 @@
+package gorm
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+	"time"
+
+	"github.com/ngorm/common"
+	"github.com/ngorm/ngorm/model"
+)
+
+type postgres struct {
+	common.Dialect
+}
+
+func (postgres) GetName() string {
+	return "postgres"
+}
+
+func (postgres) BindVar(i int) string {
+	return fmt.Sprintf("$%v", i)
+}
+
+func (postgres) DataTypeOf(field *model.StructField) (string, error) {
+	dataValue, sqlType, size, additionalType :=
+		model.ParseFieldStructForDialect(field)
+	if sqlType == "" {
+		switch dataValue.Kind() {
+		case reflect.Bool:
+			sqlType = "boolean"
+		case reflect.Int, reflect.Int8,
+			reflect.Int16, reflect.Int32,
+			reflect.Uint, reflect.Uint8,
+			reflect.Uint16, reflect.Uint32,
+			reflect.Uintptr:
+			if _, ok := field.TagSettings["AUTO_INCREMENT"]; ok || field.IsPrimaryKey {
+				field.TagSettings["AUTO_INCREMENT"] = "AUTO_INCREMENT"
+				sqlType = "serial"
+			} else {
+				sqlType = "integer"
+			}
+		case reflect.Int64, reflect.Uint64:
+			if _, ok := field.TagSettings["AUTO_INCREMENT"]; ok || field.IsPrimaryKey {
+				field.TagSettings["AUTO_INCREMENT"] = "AUTO_INCREMENT"
+				sqlType = "bigserial"
+			} else {
+				sqlType = "bigint"
+			}
+		case reflect.Float32, reflect.Float64:
+			sqlType = "numeric"
+		case reflect.String:
+			if _, ok := field.TagSettings["SIZE"]; !ok {
+				size = 0 // if SIZE haven't been set, use `text` as the default type, as there are no performance different
+			}
+
+			if size > 0 && size < 65532 {
+				sqlType = fmt.Sprintf("varchar(%d)", size)
+			} else {
+				sqlType = "text"
+			}
+		case reflect.Struct:
+			if _, ok := dataValue.Interface().(time.Time); ok {
+				sqlType = "timestamp with time zone"
+			}
+		case reflect.Map:
+			if dataValue.Type().Name() == "Hstore" {
+				sqlType = "hstore"
+			}
+		default:
+			if isByteArrayOrSlice(dataValue) {
+				sqlType = "bytea"
+			} else if isUUID(dataValue) {
+				sqlType = "uuid"
+			}
+		}
+	}
+
+	if sqlType == "" {
+		return "", fmt.Errorf("invalid sql type %s (%s) for postgres",
+			dataValue.Type().Name(), dataValue.Kind().String())
+	}
+
+	if strings.TrimSpace(additionalType) == "" {
+		return sqlType, nil
+	}
+	return fmt.Sprintf("%v %v", sqlType, additionalType), nil
+}
+
+func (s postgres) HasIndex(tableName string, indexName string) bool {
+	var count int
+	s.DB.QueryRow(
+		"SELECT count(*) FROM pg_indexes WHERE tablename = $1 AND indexname = $2",
+		tableName, indexName).Scan(&count)
+	return count > 0
+}
+
+func (s postgres) HasForeignKey(tableName string, foreignKeyName string) bool {
+	var count int
+	query := `
+SELECT Count(con.conname)
+FROM   pg_constraint con
+WHERE  $1 :: regclass :: oid = con.conrelid
+       AND con.conname = $2
+       AND con.contype = 'f'
+	`
+	s.DB.QueryRow(query, tableName, foreignKeyName).Scan(&count)
+	return count > 0
+}
+
+func (s postgres) HasTable(tableName string) bool {
+	var count int
+	query := `
+SELECT Count(*)
+FROM   information_schema.tables
+WHERE  table_name = $1
+       AND table_type = 'BASE TABLE'
+	`
+	s.DB.QueryRow(query, tableName).Scan(&count)
+	return count > 0
+}
+
+func (s postgres) HasColumn(tableName string, columnName string) bool {
+	var count int
+	query := `
+SELECT Count(*)
+FROM   information_schema.columns
+WHERE  table_name = $1
+       AND column_name = $2
+	`
+	s.DB.QueryRow(query, tableName, columnName).Scan(&count)
+	return count > 0
+}
+
+func (s postgres) CurrentDatabase() (name string) {
+	s.DB.QueryRow("SELECT CURRENT_DATABASE()").Scan(&name)
+	return
+}
+
+func (s postgres) LastInsertIDReturningSuffix(tableName, key string) string {
+	return fmt.Sprintf("RETURNING %v.%v", tableName, key)
+}
+
+func (postgres) SupportLastInsertID() bool {
+	return false
+}
+
+func isByteArrayOrSlice(value reflect.Value) bool {
+	return (value.Kind() == reflect.Array || value.Kind() == reflect.Slice) && value.Type().Elem() == reflect.TypeOf(uint8(0))
+}
+
+func isUUID(value reflect.Value) bool {
+	if value.Kind() != reflect.Array || value.Type().Len() != 16 {
+		return false
+	}
+	typename := value.Type().Name()
+	lower := strings.ToLower(typename)
+	return "uuid" == lower || "guid" == lower
+}