diff --git a/database/gdb/gdb_model_lock.go b/database/gdb/gdb_model_lock.go index a207a126e8d..3fb4e1f45e4 100644 --- a/database/gdb/gdb_model_lock.go +++ b/database/gdb/gdb_model_lock.go @@ -6,16 +6,124 @@ package gdb +// Lock clause constants for different databases. +// These constants provide type-safe and IDE-friendly access to various lock syntaxes. +const ( + // Common lock clauses (supported by most databases) + LockForUpdate = "FOR UPDATE" + LockForUpdateSkipLocked = "FOR UPDATE SKIP LOCKED" + + // MySQL lock clauses + LockInShareMode = "LOCK IN SHARE MODE" // MySQL legacy syntax + LockForShare = "FOR SHARE" // MySQL 8.0+ and PostgreSQL + LockForUpdateNowait = "FOR UPDATE NOWAIT" // MySQL 8.0+ and Oracle + + // PostgreSQL specific lock clauses + LockForNoKeyUpdate = "FOR NO KEY UPDATE" + LockForKeyShare = "FOR KEY SHARE" + LockForShareNowait = "FOR SHARE NOWAIT" + LockForShareSkipLocked = "FOR SHARE SKIP LOCKED" + LockForNoKeyUpdateNowait = "FOR NO KEY UPDATE NOWAIT" + LockForNoKeyUpdateSkipLocked = "FOR NO KEY UPDATE SKIP LOCKED" + LockForKeyShareNowait = "FOR KEY SHARE NOWAIT" + LockForKeyShareSkipLocked = "FOR KEY SHARE SKIP LOCKED" + + // Oracle specific lock clauses + LockForUpdateWait5 = "FOR UPDATE WAIT 5" + LockForUpdateWait10 = "FOR UPDATE WAIT 10" + LockForUpdateWait30 = "FOR UPDATE WAIT 30" + + // SQL Server lock hints (use with WITH clause) + LockWithUpdLock = "WITH (UPDLOCK)" + LockWithHoldLock = "WITH (HOLDLOCK)" + LockWithXLock = "WITH (XLOCK)" + LockWithTabLock = "WITH (TABLOCK)" + LockWithNoLock = "WITH (NOLOCK)" + LockWithUpdLockHoldLock = "WITH (UPDLOCK, HOLDLOCK)" +) + +// Lock sets a custom lock clause for the current operation. +// This is a generic method that allows you to specify any lock syntax supported by your database. +// You can use predefined constants or custom strings. +// +// Database-specific lock syntax support: +// +// PostgreSQL (most comprehensive): +// - "FOR UPDATE" - Exclusive lock, blocks all access +// - "FOR NO KEY UPDATE" - Weaker exclusive lock, doesn't block FOR KEY SHARE +// - "FOR SHARE" - Shared lock, allows reads but blocks writes +// - "FOR KEY SHARE" - Weakest lock, only locks key values +// - All above can be combined with: +// - "NOWAIT" - Return immediately if lock cannot be acquired +// - "SKIP LOCKED" - Skip locked rows instead of waiting +// +// MySQL: +// - "FOR UPDATE" - Exclusive lock (all versions) +// - "LOCK IN SHARE MODE" - Shared lock (legacy syntax) +// - "FOR SHARE" - Shared lock (MySQL 8.0+) +// - "FOR UPDATE NOWAIT" - MySQL 8.0+ only +// - "FOR UPDATE SKIP LOCKED" - MySQL 8.0+ only +// +// Oracle: +// - "FOR UPDATE" - Exclusive lock +// - "FOR UPDATE NOWAIT" - Exclusive lock, no wait +// - "FOR UPDATE SKIP LOCKED" - Exclusive lock, skip locked rows +// - "FOR UPDATE WAIT n" - Exclusive lock, wait n seconds +// - "FOR UPDATE OF column_list" - Lock specific columns +// +// SQL Server (uses WITH hints): +// - "WITH (UPDLOCK)" - Update lock +// - "WITH (HOLDLOCK)" - Hold lock until transaction end +// - "WITH (XLOCK)" - Exclusive lock +// - "WITH (TABLOCK)" - Table lock +// - "WITH (NOLOCK)" - No lock (dirty read) +// - "WITH (UPDLOCK, HOLDLOCK)" - Combined update and hold lock +// +// SQLite: +// - Limited locking support, database-level locks only +// - No row-level lock syntax supported +// +// Usage examples: +// +// db.Model("users").Lock("FOR UPDATE NOWAIT").Where("id", 1).One() +// db.Model("users").Lock("FOR SHARE SKIP LOCKED").Where("status", "active").All() +// db.Model("users").Lock("WITH (UPDLOCK)").Where("id", 1).One() // SQL Server +// db.Model("users").Lock("FOR UPDATE OF name, email").Where("id", 1).One() // Oracle +// db.Model("users").Lock("FOR UPDATE WAIT 15").Where("id", 1).One() // Oracle custom wait +// +// Or use predefined constants for better IDE support: +// +// db.Model("users").Lock(gdb.LockForUpdateNowait).Where("id", 1).One() +// db.Model("users").Lock(gdb.LockForShareSkipLocked).Where("status", "active").All() +func (m *Model) Lock(lockClause string) *Model { + model := m.getModel() + model.lockInfo = lockClause + return model +} + // LockUpdate sets the lock for update for current operation. +// This is equivalent to Lock("FOR UPDATE"). func (m *Model) LockUpdate() *Model { model := m.getModel() - model.lockInfo = "FOR UPDATE" + model.lockInfo = LockForUpdate + return model +} + +// LockUpdateSkipLocked sets the lock for update with skip locked behavior for current operation. +// It skips the locked rows. +// This is equivalent to Lock("FOR UPDATE SKIP LOCKED"). +// Note: Supported by PostgreSQL, Oracle, and MySQL 8.0+. +func (m *Model) LockUpdateSkipLocked() *Model { + model := m.getModel() + model.lockInfo = LockForUpdateSkipLocked return model } // LockShared sets the lock in share mode for current operation. +// This is equivalent to Lock("LOCK IN SHARE MODE") for MySQL or Lock("FOR SHARE") for PostgreSQL. +// Note: For maximum compatibility, this uses MySQL's legacy syntax. func (m *Model) LockShared() *Model { model := m.getModel() - model.lockInfo = "LOCK IN SHARE MODE" + model.lockInfo = LockInShareMode return model }