forked from gwenn/gosqlite
/
meta.go
327 lines (305 loc) · 9.44 KB
/
meta.go
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// Copyright 2010 The Go 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 sqlite
/*
#include <sqlite3.h>
#include <stdlib.h>
// cgo doesn't support varargs
static char *my_mprintf(char *zFormat, char *arg) {
return sqlite3_mprintf(zFormat, arg);
}
static char *my_mprintf2(char *zFormat, char *arg1, char *arg2) {
return sqlite3_mprintf(zFormat, arg1, arg2);
}
// just to get ride of warning
static int my_table_column_metadata(
sqlite3 *db,
const char *zDbName,
const char *zTableName,
const char *zColumnName,
char **pzDataType,
char **pzCollSeq,
int *pNotNull,
int *pPrimaryKey,
int *pAutoinc
) {
return sqlite3_table_column_metadata(db, zDbName, zTableName, zColumnName,
(char const **)pzDataType, (char const **)pzCollSeq, pNotNull, pPrimaryKey, pAutoinc);
}
*/
import "C"
import (
"fmt"
"unsafe"
)
// Databases returns one couple (name, file) for each database attached to the current database connection.
// (See http://www.sqlite.org/pragma.html#pragma_database_list)
func (c *Conn) Databases() (map[string]string, error) {
s, err := c.prepare("PRAGMA database_list")
if err != nil {
return nil, err
}
defer s.finalize()
var databases map[string]string = make(map[string]string)
var name, file string
err = s.Select(func(s *Stmt) (err error) {
if err = s.Scan(nil, &name, &file); err != nil {
return
}
databases[name] = file
return
})
if err != nil {
return nil, err
}
return databases, nil
}
// Tables returns tables (no view) from 'sqlite_master' and filters system tables out.
// TODO create Views method to return views...
func (c *Conn) Tables(dbName string) ([]string, error) {
var sql string
if len(dbName) == 0 {
sql = "SELECT name FROM sqlite_master WHERE type IN ('table') AND name NOT LIKE 'sqlite_%'"
} else {
sql = Mprintf("SELECT name FROM %Q.sqlite_master WHERE type IN ('table') AND name NOT LIKE 'sqlite_%%'", dbName)
}
s, err := c.prepare(sql)
if err != nil {
return nil, err
}
defer s.finalize()
var tables []string = make([]string, 0, 20)
err = s.Select(func(s *Stmt) (err error) {
name, _ := s.ScanText(0)
tables = append(tables, name)
return
})
if err != nil {
return nil, err
}
return tables, nil
}
// See Conn.Columns/IndexColumns
type Column struct {
Cid int
Name string
DataType string
NotNull bool
DfltValue string // FIXME type ?
Pk bool
Autoinc bool
CollSeq string
}
// Columns returns a description for each column in the named table.
// Column.Autoinc and Column.CollSeq are left unspecified.
// (See http://www.sqlite.org/pragma.html#pragma_table_info)
func (c *Conn) Columns(dbName, table string) ([]Column, error) {
var pragma string
if len(dbName) == 0 {
pragma = Mprintf("PRAGMA table_info(%Q)", table)
} else {
pragma = Mprintf2("PRAGMA %Q.table_info(%Q)", dbName, table)
}
s, err := c.prepare(pragma)
if err != nil {
return nil, err
}
defer s.finalize()
var columns []Column = make([]Column, 0, 20)
err = s.Select(func(s *Stmt) (err error) {
c := Column{}
if err = s.Scan(&c.Cid, &c.Name, &c.DataType, &c.NotNull, &c.DfltValue, &c.Pk); err != nil {
return
}
columns = append(columns, c)
return
})
if err != nil {
return nil, err
}
return columns, nil
}
// Column extracts metadata about a column of a table.
// Column.Cid and Column.DfltValue are left unspecified.
// (See http://sqlite.org/c3ref/table_column_metadata.html)
func (c *Conn) Column(dbName, tableName, columnName string) (*Column, error) {
var zDbName *C.char
if len(dbName) > 0 {
zDbName = C.CString(dbName)
defer C.free(unsafe.Pointer(zDbName))
}
zTableName := C.CString(tableName)
defer C.free(unsafe.Pointer(zTableName))
zColumnName := C.CString(columnName)
defer C.free(unsafe.Pointer(zColumnName))
var zDataType, zCollSeq *C.char
var notNull, primaryKey, autoinc C.int
rv := C.my_table_column_metadata(c.db, zDbName, zTableName, zColumnName, &zDataType, &zCollSeq,
¬Null, &primaryKey, &autoinc)
if rv != C.SQLITE_OK {
return nil, c.error(rv, fmt.Sprintf("Conn.Column(db: %q, tbl: %q, col: %q)", dbName, tableName, columnName))
}
return &Column{-1, columnName, C.GoString(zDataType), notNull == 1, "", primaryKey == 1,
autoinc == 1, C.GoString(zCollSeq)}, nil
}
// ColumnDatabaseName returns the database
// that is the origin of a particular result column in SELECT statement.
// The left-most column is column 0.
// (See http://www.sqlite.org/c3ref/column_database_name.html)
func (s *Stmt) ColumnDatabaseName(index int) string {
return C.GoString(C.sqlite3_column_database_name(s.stmt, C.int(index)))
}
// ColumnTableName returns the original un-aliased table name
// that is the origin of a particular result column in SELECT statement.
// The left-most column is column 0.
// (See http://www.sqlite.org/c3ref/column_database_name.html)
func (s *Stmt) ColumnTableName(index int) string {
return C.GoString(C.sqlite3_column_table_name(s.stmt, C.int(index)))
}
// ColumnOriginName returns the original un-aliased table column name
// that is the origin of a particular result column in SELECT statement.
// The left-most column is column 0.
// (See http://www.sqlite.org/c3ref/column_database_name.html)
func (s *Stmt) ColumnOriginName(index int) string {
return C.GoString(C.sqlite3_column_origin_name(s.stmt, C.int(index)))
}
// ColumnDeclaredType returns the declared type of the table column of a particular result column in SELECT statement. If the result column is an expression or subquery, then a NULL pointer is returned.
// The left-most column is column 0.
// (See http://www.sqlite.org/c3ref/column_decltype.html)
func (s *Stmt) ColumnDeclaredType(index int) string {
return C.GoString(C.sqlite3_column_decltype(s.stmt, C.int(index)))
}
// See Conn.ForeignKeys
type ForeignKey struct {
Table string
From []string
To []string
}
// ForeignKeys returns one description for each foreign key that references a column in the argument table.
// (See http://www.sqlite.org/pragma.html#pragma_foreign_key_list)
func (c *Conn) ForeignKeys(dbName, table string) (map[int]*ForeignKey, error) {
var pragma string
if len(dbName) == 0 {
pragma = Mprintf("PRAGMA foreign_key_list(%Q)", table)
} else {
pragma = Mprintf2("PRAGMA %Q.foreign_key_list(%Q)", dbName, table)
}
s, err := c.prepare(pragma)
if err != nil {
return nil, err
}
defer s.finalize()
var fks = make(map[int]*ForeignKey)
var id, seq int
var ref, from, to string
err = s.Select(func(s *Stmt) (err error) {
if err = s.NamedScan("id", &id, "seq", &seq, "table", &ref, "from", &from, "to", &to); err != nil {
return
}
fk, ex := fks[id]
if !ex {
fk = &ForeignKey{Table: ref}
fks[id] = fk
}
// TODO Ensure columns are appended in the correct order...
fk.From = append(fk.From, from)
fk.To = append(fk.To, to)
return
})
if err != nil {
return nil, err
}
return fks, nil
}
// See Conn.Indexes
type Index struct {
Name string
Unique bool
}
// Indexes returns one description for each index associated with the given table.
// (See http://www.sqlite.org/pragma.html#pragma_index_list)
func (c *Conn) Indexes(dbName, table string) ([]Index, error) {
var pragma string
if len(dbName) == 0 {
pragma = Mprintf("PRAGMA index_list(%Q)", table)
} else {
pragma = Mprintf2("PRAGMA %Q.index_list(%Q)", dbName, table)
}
s, err := c.prepare(pragma)
if err != nil {
return nil, err
}
defer s.finalize()
var indexes []Index = make([]Index, 0, 5)
err = s.Select(func(s *Stmt) (err error) {
i := Index{}
if err = s.Scan(nil, &i.Name, &i.Unique); err != nil {
return
}
indexes = append(indexes, i)
return
})
if err != nil {
return nil, err
}
return indexes, nil
}
// IndexColumns returns one description for each column in the named index.
// Only Column.Cid and Column.Name are specified. All other fields are unspecifed.
// (See http://www.sqlite.org/pragma.html#pragma_index_info)
func (c *Conn) IndexColumns(dbName, index string) ([]Column, error) {
var pragma string
if len(dbName) == 0 {
pragma = Mprintf("PRAGMA index_info(%Q)", index)
} else {
pragma = Mprintf2("PRAGMA %Q.index_info(%Q)", dbName, index)
}
s, err := c.prepare(pragma)
if err != nil {
return nil, err
}
defer s.finalize()
var columns []Column = make([]Column, 0, 5)
err = s.Select(func(s *Stmt) (err error) {
c := Column{}
if err = s.Scan(nil, &c.Cid, &c.Name); err != nil {
return
}
columns = append(columns, c)
return
})
if err != nil {
return nil, err
}
return columns, nil
}
// Mprintf is like fmt.Printf but implements some additional formatting options
// that are useful for constructing SQL statements.
// (See http://sqlite.org/c3ref/mprintf.html)
func Mprintf(format string, arg string) string {
zSQL := mPrintf(format, arg)
defer C.sqlite3_free(unsafe.Pointer(zSQL))
return C.GoString(zSQL)
}
func mPrintf(format, arg string) *C.char {
cf := C.CString(format)
defer C.free(unsafe.Pointer(cf))
ca := C.CString(arg)
defer C.free(unsafe.Pointer(ca))
return C.my_mprintf(cf, ca)
}
// Mprintf2 is like fmt.Printf but implements some additional formatting options
// that are useful for constructing SQL statements.
// (See http://sqlite.org/c3ref/mprintf.html)
func Mprintf2(format string, arg1, arg2 string) string {
cf := C.CString(format)
defer C.free(unsafe.Pointer(cf))
ca1 := C.CString(arg1)
defer C.free(unsafe.Pointer(ca1))
ca2 := C.CString(arg2)
defer C.free(unsafe.Pointer(ca2))
zSQL := C.my_mprintf2(cf, ca1, ca2)
defer C.sqlite3_free(unsafe.Pointer(zSQL))
return C.GoString(zSQL)
}