You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: session_schema.go
    path of file: ./repos/grafana/pkg/util/xorm
    
    the code of the file until where you have to start completion: // Copyright 2016 The Xorm Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package xorm

import (
	"database/sql"
	"fmt"
	"strings"

	"xorm.io/core"
)

// Ping test if database is ok
func (session *Session) Ping() error {
	if session.isAutoClose {
		defer session.Close()
	}

	session.engine.logger.Infof("PING DATABASE %v", session.engine.DriverName())
	return session.DB().PingContext(session.ctx)
}

// CreateTable create a table according a bean
func (session *Session) CreateTable(bean any) error {
	if session.isAutoClose {
		defer session.Close()
	}

	return session.createTable(bean)
}

func (session *Session) createTable(bean any) error {
	if err := session.statement.setRefBean(bean); err != nil {
		return err
	}

	sqlStr := session.statement.genCreateTableSQL()
	_, err := session.exec(sqlStr)
	return err
}

// CreateIndexes create indexes
func (session *Session) CreateIndexes(bean any) error {
	if session.isAutoClose {
		defer session.Close()
	}

	return session.createIndexes(bean)
}

func (session *Session) createIndexes(bean any) error {
	if err := session.statement.setRefBean(bean); err != nil {
		return err
	}

	sqls := session.statement.genIndexSQL()
	for _, sqlStr := range sqls {
		_, err := session.exec(sqlStr)
		if err != nil {
			return err
		}
	}
	return nil
}

// CreateUniques create uniques
func (session *Session) CreateUniques(bean any) error {
	if session.isAutoClose {
		defer session.Close()
	}
	return session.createUniques(bean)
}

func (session *Session) createUniques(bean any) error {
	if err := session.statement.setRefBean(bean); err != nil {
		return err
	}

	sqls := session.statement.genUniqueSQL()
	for _, sqlStr := range sqls {
		_, err := session.exec(sqlStr)
		if err != nil {
			return err
		}
	}
	return nil
}

// DropIndexes drop indexes
func (session *Session) DropIndexes(bean any) error {
	if session.isAutoClose {
		defer session.Close()
	}

	return session.dropIndexes(bean)
}

func (session *Session) dropIndexes(bean any) error {
	if err := session.statement.setRefBean(bean); err != nil {
		return err
	}

	sqls := session.statement.genDelIndexSQL()
	for _, sqlStr := range sqls {
		_, err := session.exec(sqlStr)
		if err != nil {
			return err
		}
	}
	return nil
}

// DropTable drop table will drop table if exist, if drop failed, it will return error
func (session *Session) DropTable(beanOrTableName any) error {
	if session.isAutoClose {
		defer session.Close()
	}

	return session.dropTable(beanOrTableName)
}

func (session *Session) dropTable(beanOrTableName any) error {
	tableName := session.engine.TableName(beanOrTableName)
	var needDrop = true
	if !session.engine.dialect.SupportDropIfExists() {
		sqlStr, args := session.engine.dialect.TableCheckSql(tableName)
		results, err := session.queryBytes(sqlStr, args...)
		if err != nil {
			return err
		}
		needDrop = len(results) > 0
	}

	if needDrop {
		sqlStr := session.engine.Dialect().DropTableSql(session.engine.TableName(tableName, true))
		_, err := session.exec(sqlStr)
		return err
	}
	return nil
}

// IsTableExist if a table is exist
func (session *Session) IsTableExist(beanOrTableName any) (bool, error) {
	if session.isAutoClose {
		defer session.Close()
	}

	tableName := session.engine.TableName(beanOrTableName)

	return session.isTableExist(tableName)
}

func (session *Session) isTableExist(tableName string) (bool, error) {
	sqlStr, args := session.engine.dialect.TableCheckSql(tableName)
	results, err := session.queryBytes(sqlStr, args...)
	return len(results) > 0, err
}

// IsTableEmpty if table have any records
func (session *Session) IsTableEmpty(bean any) (bool, error) {
	if session.isAutoClose {
		defer session.Close()
	}
	return session.isTableEmpty(session.engine.TableName(bean))
}

func (session *Session) isTableEmpty(tableName string) (bool, error) {
	var total int64
	sqlStr := fmt.Sprintf("select count(*) from %s", session.engine.Quote(session.engine.TableName(tableName, true)))
	err := session.queryRow(sqlStr).Scan(&total)
	if err != nil {
		if err == sql.ErrNoRows {
			err = nil
		}
		return true, err
	}

	return total == 0, nil
}

// find if index is exist according cols
func (session *Session) isIndexExist2(tableName string, cols []string, unique bool) (bool, error) {
	indexes, err := session.engine.dialect.GetIndexes(tableName)
	if err != nil {
		return false, err
	}

	for _, index := range indexes {
		if sliceEq(index.Cols, cols) {
			if unique {
				return index.Type == core.UniqueType, nil
			}
			return index.Type == core.IndexType, nil
		}
	}
	return false, nil
}

func (session *Session) addColumn(colName string) error {
	col := session.statement.RefTable.GetColumn(colName)
	sql, args := session.statement.genAddColumnStr(col)
	_, err := session.exec(sql, args...)
	return err
}

func (session *Session) addIndex(tableName, idxName string) error {
	index := session.statement.RefTable.Indexe
    
func (session *Session) Sync2(beans ...any) error {
	engine := session.engine

	if session.isAutoClose {
		session.isAutoClose = false
		defer session.Close()
	}

	tables, err := engine.dialect.GetTables()
	if err != nil {
		return err
	}

	session.autoResetStatement = false
	defer func() {
		session.autoResetStatement = true
		session.resetStatement()
	}()

	for _, bean := range beans {
		v := rValue(bean)
		table, err := engine.mapType(v)
		if err != nil {
			return err
		}
		var tbName string
		if len(session.statement.AltTableName) > 0 {
			tbName = session.statement.AltTableName
		} else {
			tbName = engine.TableName(bean)
		}
		tbNameWithSchema := engine.tbNameWithSchema(tbName)

		var oriTable *core.Table
		for _, tb := range tables {
			if strings.EqualFold(engine.tbNameWithSchema(tb.Name), engine.tbNameWithSchema(tbName)) {
				oriTable = tb
				break
			}
		}

		// this is a new table
		if oriTable == nil {
			err = session.StoreEngine(session.statement.StoreEngine).createTable(bean)
			if err != nil {
				return err
			}

			err = session.createUniques(bean)
			if err != nil {
				return err
			}

			err = session.createIndexes(bean)
			if err != nil {
				return err
			}
			continue
		}

		// this will modify an old table
		if err = engine.loadTableInfo(oriTable); err != nil {
			return err
		}

		// check columns
		for _, col := range table.Columns() {
			var oriCol *core.Column
			for _, col2 := range oriTable.Columns() {
				if strings.EqualFold(col.Name, col2.Name) {
					oriCol = col2
					break
				}
			}

			// column is not exist on table
			if oriCol == nil {
				session.statement.RefTable = table
				session.statement.tableName = tbNameWithSchema
				if err = session.addColumn(col.Name); err != nil {
					return err
				}
				continue
			}

			err = nil
			expectedType := engine.dialect.SqlType(col)
			curType := engine.dialect.SqlType(oriCol)
			if expectedType != curType {
				if expectedType == core.Text &&
					strings.HasPrefix(curType, core.Varchar) {
					// currently only support mysql & postgres
					if engine.dialect.DBType() == core.MYSQL ||
						engine.dialect.DBType() == core.POSTGRES {
						engine.logger.Infof("Table %s column %s change type from %s to %s\n",
							tbNameWithSchema, col.Name, curType, expectedType)
						_, err = session.exec(engine.dialect.ModifyColumnSql(tbNameWithSchema, col))
					} else {
						engine.logger.Warnf("Table %s column %s db type is %s, struct type is %s\n",
							tbNameWithSchema, col.Name, curType, expectedType)
					}
				} else if strings.HasPrefix(curType, core.Varchar) && strings.HasPrefix(expectedType, core.Varchar) {
					if engine.dialect.DBType() == core.MYSQL {
						if oriCol.Length < col.Length {
							engine.logger.Infof("Table %s column %s change type from varchar(%d) to varchar(%d)\n",
								tbNameWithSchema, col.Name, oriCol.Length, col.Length)
							_, err = session.exec(engine.dialect.ModifyColumnSql(tbNameWithSchema, col))
						}
					}
				} else {
					if !(strings.HasPrefix(curType, expectedType) && curType[len(expectedType)] == '(') {
						engine.logger.Warnf("Table %s column %s db type is %s, struct type is %s",
							tbNameWithSchema, col.Name, curType, expectedType)
					}
				}
			} else if expectedType == core.Varchar {
				if engine.dialect.DBType() == core.MYSQL {
					if oriCol.Length < col.Length {
						engine.logger.Infof("Table %s column %s change type from varchar(%d) to varchar(%d)\n",
							tbNameWithSchema, col.Name, oriCol.Length, col.Length)
						_, err = session.exec(engine.dialect.ModifyColumnSql(tbNameWithSchema, col))
					}
				}
			}

			if col.Default != oriCol.Default {
				switch {
				case col.IsAutoIncrement: // For autoincrement column, don't check default
				case (col.SQLType.Name == core.Bool || col.SQLType.Name == core.Boolean) &&
					((strings.EqualFold(col.Default, "true") && oriCol.Default == "1") ||
						(strings.EqualFold(col.Default, "false") && oriCol.Default == "0")):
				default:
					engine.logger.Warnf("Table %s Column %s db default is %s, struct default is %s",
						tbName, col.Name, oriCol.Default, col.Default)
				}
			}
			if col.Nullable != oriCol.Nullable {
				engine.logger.Warnf("Table %s Column %s db nullable is %v, struct nullable is %v",
					tbName, col.Name, oriCol.Nullable, col.Nullable)
			}

			if err != nil {
				return err
			}
		}

		var foundIndexNames = make(map[string]bool)
		var addedNames = make(map[string]*core.Index)

		for name, index := range table.Indexes {
			var oriIndex *core.Index
			for name2, index2 := range oriTable.Indexes {
				if index.Equal(index2) {
					oriIndex = index2
					foundIndexNames[name2] = true
					break
				}
			}

			if oriIndex != nil {
				if oriIndex.Type != index.Type {
					sql := engine.dialect.DropIndexSql(tbNameWithSchema, oriIndex)
					_, err = session.exec(sql)
					if err != nil {
						return err
					}
					oriIndex = nil
				}
			}

			if oriIndex == nil {
				addedNames[name] = index
			}
		}

		for name2, index2 := range oriTable.Indexes {
			if _, ok := foundIndexNames[name2]; !ok {
				sql := engine.dialect.DropIndexSql(tbNameWithSchema, index2)
				_, err = session.exec(sql)
				if err != nil {
					return err
				}
			}
		}

		for name, index := range addedNames {
			if index.Type == core.UniqueType {
				session.statement.RefTable = table
				session.statement.tableName = tbNameWithSchema
				err = session.addUnique(tbNameWithSchema, name)
			} else if index.Type == core.IndexType {
				session.statement.RefTable = table
				session.statement.tableName = tbNameWithSchema
				err = session.addIndex(tbNameWithSchema, name)
			}
			if err != nil {
				return err
			}
		}

		// check all the columns which removed from struct fields but left on database tables.
		for _, colName := range oriTable.ColumnsSeq() {
			if table.GetColumn(colName) == nil {
				engine.logger.Warnf("Table %s has column %s but struct has not related field", engine.TableName(oriTable.Name, true), colName)
			}
		}
	}

	return nil
}